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Index: projects/hps_head/share/man/man9/Makefile
===================================================================
--- projects/hps_head/share/man/man9/Makefile
+++ projects/hps_head/share/man/man9/Makefile
@@ -1573,6 +1573,7 @@
timeout.9 callout_active.9 \
timeout.9 callout_deactivate.9 \
timeout.9 callout_drain.9 \
+ timeout.9 callout_drain_async.9 \
timeout.9 callout_handle_init.9 \
timeout.9 callout_init.9 \
timeout.9 callout_init_mtx.9 \
Index: projects/hps_head/share/man/man9/timeout.9
===================================================================
--- projects/hps_head/share/man/man9/timeout.9
+++ projects/hps_head/share/man/man9/timeout.9
@@ -29,13 +29,14 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 8, 2014
+.Dd January 24, 2015
.Dt TIMEOUT 9
.Os
.Sh NAME
.Nm callout_active ,
.Nm callout_deactivate ,
.Nm callout_drain ,
+.Nm callout_drain_async ,
.Nm callout_handle_init ,
.Nm callout_init ,
.Nm callout_init_mtx ,
@@ -63,256 +64,234 @@
.In sys/systm.h
.Bd -literal
typedef void timeout_t (void *);
+typedef void callout_func_t (void *);
.Ed
-.Ft int
-.Fn callout_active "struct callout *c"
-.Ft void
-.Fn callout_deactivate "struct callout *c"
-.Ft int
-.Fn callout_drain "struct callout *c"
-.Ft void
-.Fn callout_handle_init "struct callout_handle *handle"
-.Bd -literal
-struct callout_handle handle = CALLOUT_HANDLE_INITIALIZER(&handle);
-.Ed
-.Ft void
-.Fn callout_init "struct callout *c" "int mpsafe"
-.Ft void
-.Fn callout_init_mtx "struct callout *c" "struct mtx *mtx" "int flags"
-.Ft void
-.Fn callout_init_rm "struct callout *c" "struct rmlock *rm" "int flags"
-.Ft void
-.Fn callout_init_rw "struct callout *c" "struct rwlock *rw" "int flags"
-.Ft int
-.Fn callout_pending "struct callout *c"
-.Ft int
-.Fn callout_reset "struct callout *c" "int ticks" "timeout_t *func" "void *arg"
-.Ft int
-.Fn callout_reset_curcpu "struct callout *c" "int ticks" "timeout_t *func" \
-"void *arg"
-.Ft int
-.Fn callout_reset_on "struct callout *c" "int ticks" "timeout_t *func" \
-"void *arg" "int cpu"
-.Ft int
-.Fn callout_reset_sbt "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int flags"
-.Ft int
-.Fn callout_reset_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int flags"
-.Ft int
-.Fn callout_reset_sbt_on "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int cpu" "int flags"
-.Ft int
-.Fn callout_schedule "struct callout *c" "int ticks"
-.Ft int
-.Fn callout_schedule_curcpu "struct callout *c" "int ticks"
-.Ft int
-.Fn callout_schedule_on "struct callout *c" "int ticks" "int cpu"
-.Ft int
-.Fn callout_schedule_sbt "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int flags"
-.Ft int
-.Fn callout_schedule_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int flags"
-.Ft int
-.Fn callout_schedule_sbt_on "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int cpu" "int flags"
-.Ft int
-.Fn callout_stop "struct callout *c"
-.Ft struct callout_handle
-.Fn timeout "timeout_t *func" "void *arg" "int ticks"
-.Ft void
-.Fn untimeout "timeout_t *func" "void *arg" "struct callout_handle handle"
.Sh DESCRIPTION
The
.Nm callout
-API is used to schedule a call to an arbitrary function at a specific
-time in the future.
-Consumers of this API are required to allocate a callout structure
-.Pq struct callout
+API is used to schedule a one-time call to an arbitrary function at a
+specific time in the future.
+Consumers of this API are required to allocate a
+.Ft struct callout
for each pending function invocation.
-This structure stores state about the pending function invocation including
-the function to be called and the time at which the function should be invoked.
-Pending function calls can be cancelled or rescheduled to a different time.
-In addition,
-a callout structure may be reused to schedule a new function call after a
-scheduled call is completed.
-.Pp
-Callouts only provide a single-shot mode.
-If a consumer requires a periodic timer,
-it must explicitly reschedule each function call.
-This is normally done by rescheduling the subsequent call within the called
-function.
-.Pp
-Callout functions must not sleep.
-They may not acquire sleepable locks,
-wait on condition variables,
-perform blocking allocation requests,
-or invoke any other action that might sleep.
-.Pp
-Each callout structure must be initialized by
-.Fn callout_init ,
-.Fn callout_init_mtx ,
-.Fn callout_init_rm ,
-or
-.Fn callout_init_rw
-before it is passed to any of the other callout functions.
The
+.Ft struct callout
+stores the full state about any pending function call and
+must be drained by a call to
+.Fn callout_drain
+or
+.Fn callout_drain_async
+before freeing.
+.Sh INITIALIZATION
+.Ft void
+.Fn callout_handle_init "struct callout_handle *handle"
+This function is deprecated.
+Please use
.Fn callout_init
-function initializes a callout structure in
-.Fa c
-that is not associated with a specific lock.
+instead.
+This function is used to prepare a
+.Ft struct callout_handle
+before it can be used the first time.
+If this function is called on a pending timeout, the pending timeout
+cannot be cancelled and the
+.Fn untimeout
+function will return as if no timeout was pending.
+.Pp
+.Fn CALLOUT_HANDLE_INITIALIZER "&handle"
+This macro is deprecated.
+This macro is used to statically initialize a
+.Ft struct callout_handle .
+Please use
+.Fn callout_init
+instead.
+.Pp
+.Ft void
+.Fn callout_init "struct callout *c" "int mpsafe"
+This function prepares a
+.Ft struct callout
+before it can be used.
+This function should not be used when the callout is pending a timeout.
If the
.Fa mpsafe
-argument is zero,
-the callout structure is not considered to be
-.Dq multi-processor safe ;
-and the Giant lock will be acquired before calling the callout function
-and released when the callout function returns.
-.Pp
-The
-.Fn callout_init_mtx ,
-.Fn callout_init_rm ,
-and
-.Fn callout_init_rw
-functions initialize a callout structure in
-.Fa c
-that is associated with a specific lock.
-The lock is specified by the
-.Fa mtx ,
-.Fa rm ,
-or
-.Fa rw
-parameter.
-The associated lock must be held while stopping or rescheduling the
-callout.
-The callout subsystem acquires the associated lock before calling the
-callout function and releases it after the function returns.
-If the callout was cancelled while the callout subsystem waited for the
-associated lock,
-the callout function is not called,
-and the associated lock is released.
-This ensures that stopping or rescheduling the callout will abort any
-previously scheduled invocation.
-.Pp
-Only regular mutexes may be used with
-.Fn callout_init_mtx ;
-spin mutexes are not supported.
-A sleepable read-mostly lock
-.Po
-one initialized with the
-.Dv RM_SLEEPABLE
-flag
-.Pc
-may not be used with
-.Fn callout_init_rm .
-Similarly, other sleepable lock types such as
-.Xr sx 9
-and
-.Xr lockmgr 9
-cannot be used with callouts because sleeping is not permitted in
-the callout subsystem.
+argument is non-zero, the callback function will be running unlocked
+and the callback is so-called "mpsafe".
+.Bf Sy
+It is the application's entire responsibility to not call any
+.Fn callout_xxx
+functions, including the
+.Fn callout_drain
+function, simultaneously on the same callout when the
+.Fa mpsafe
+argument is non-zero.
+Otherwise, undefined behavior can happen.
+Avoid simultaneous calls by obtaining an exclusive lock before calling
+any
+.Fn callout_xxx
+functions other than the
+.Fn callout_drain
+function.
+.Ef
+If the
+.Fa mpsafe
+argument is zero, the Giant mutex will be locked before the callback
+function is called.
+If the
+.Fa mpsafe
+argument is zero, the Giant mutex is expected to be locked when calling
+any
+.Fn callout_xxx
+functions which start and stop a callout other than the
+.Fn callout_drain
+function.
.Pp
-These
+.Ft void
+.Fn callout_init_mtx "struct callout *c" "struct mtx *mtx" "int flags"
+This function prepares a
+.Ft struct callout
+before it can be used.
+This function should not be used when the callout is pending a timeout.
+The
+.Fa mtx
+argument is a pointer to a valid spinlock type of mutex or a valid
+regular non-sleepable mutex which the callback subsystem will lock
+before calling the callback function.
+The specified mutex is expected to be locked when calling any
+.Fn callout_xxx
+functions which start and stop a callout other than the
+.Fn callout_drain
+function.
+Valid
.Fa flags
-may be specified for
-.Fn callout_init_mtx ,
-.Fn callout_init_rm ,
-or
-.Fn callout_init_rw :
+are:
.Bl -tag -width ".Dv CALLOUT_RETURNUNLOCKED"
.It Dv CALLOUT_RETURNUNLOCKED
-The callout function will release the associated lock itself,
-so the callout subsystem should not attempt to unlock it
-after the callout function returns.
-.It Dv CALLOUT_SHAREDLOCK
-The lock is only acquired in read mode when running the callout handler.
-This flag is ignored by
-.Fn callout_init_mtx .
+The callout function is assumed to have released the specified mutex
+before returning.
+.It Dv 0
+The callout subsystem will release the specified mutex after the
+callout function has returned.
.El
.Pp
-The function
-.Fn callout_stop
-cancels a callout
-.Fa c
-if it is currently pending.
-If the callout is pending, then
-.Fn callout_stop
-returns a non-zero value.
-If the callout is not set,
-has already been serviced,
-or is currently being serviced,
-then zero will be returned.
-If the callout has an associated lock,
-then that lock must be held when this function is called.
-.Pp
-The function
-.Fn callout_drain
-is identical to
-.Fn callout_stop
-except that it will wait for the callout
-.Fa c
-to complete if it is already in progress.
-This function MUST NOT be called while holding any
-locks on which the callout might block, or deadlock will result.
-Note that if the callout subsystem has already begun processing this
-callout, then the callout function may be invoked before
-.Fn callout_drain
-returns.
-However, the callout subsystem does guarantee that the callout will be
-fully stopped before
-.Fn callout_drain
-returns.
+.Ft void
+.Fn callout_init_rm "struct callout *c" "struct rmlock *rm" "int flags"
+This function is similar to
+.Fn callout_init_mtx ,
+but it accepts a read-mostly type of lock.
+The read-mostly lock must not be initialized with the
+.Dv RM_SLEEPABLE
+flag.
.Pp
-The
+.Ft void
+.Fn callout_init_rw "struct callout *c" "struct rwlock *rw" "int flags"
+This function is similar to
+.Fn callout_init_mtx ,
+but it accepts a read/write type of lock.
+.Sh SCHEDULING CALLOUTS
+.Ft struct callout_handle
+.Fn timeout "timeout_t *func" "void *arg" "int ticks"
+This function is deprecated.
+Please use
.Fn callout_reset
-and
-.Fn callout_schedule
-function families schedule a future function invocation for callout
-.Fa c .
-If
-.Fa c
-already has a pending callout,
-it is cancelled before the new invocation is scheduled.
-These functions return a non-zero value if a pending callout was cancelled
-and zero if there was no pending callout.
-If the callout has an associated lock,
-then that lock must be held when any of these functions are called.
-.Pp
-The time at which the callout function will be invoked is determined by
-either the
-.Fa ticks
-argument or the
-.Fa sbt ,
-.Fa pr ,
-and
-.Fa flags
-arguments.
-When
-.Fa ticks
-is used,
-the callout is scheduled to execute after
+instead.
+This function schedules a call to
+.Fa func
+to take place after
.Fa ticks Ns No /hz
seconds.
Non-positive values of
.Fa ticks
are silently converted to the value
.Sq 1 .
-.Pp
The
-.Fa sbt ,
-.Fa pr ,
-and
-.Fa flags
-arguments provide more control over the scheduled time including
-support for higher resolution times,
-specifying the precision of the scheduled time,
-and setting an absolute deadline instead of a relative timeout.
-The callout is scheduled to execute in a time window which begins at
-the time specified in
+.Fa func
+argument is a valid pointer to a function that takes a single
+.Fa void *
+argument.
+Upon invocation, the
+.Fa func
+function will receive
+.Fa arg
+as its only argument.
+The Giant lock is locked when the
+.Fa arg
+function is invoked and should not be unlocked by this function.
+The returned value from
+.Fn timeout
+is a
+.Ft struct callout_handle
+structure which can be used in conjunction with the
+.Fn untimeout
+function to request that a scheduled timeout be cancelled.
+As handles are recycled by the system, it is possible, although unlikely,
+that a handle from one invocation of
+.Fn timeout
+may match the handle of another invocation of
+.Fn timeout
+if both calls used the same function pointer and argument, and the first
+timeout is expired or cancelled before the second call.
+Please ensure that the function and argument pointers are unique when using this function.
+.Pp
+.Ft int
+.Fn callout_reset "struct callout *c" "int ticks" "callout_func_t *func" "void *arg"
+This function is used to schedule or re-schedule a callout.
+This function at first stops the callout given by the
+.Fa c
+argument, if any.
+Then it will start the callout given by the
+.Fa c
+argument.
+The relative time until the timeout callback happens is given by the
+.Fa ticks
+argument.
+The number of ticks in a second is defined by
+.Dv hz
+and can vary from system to system.
+This function returns a non-zero value if the given callout was pending and
+the callback function was prevented from being called.
+Otherwise, a value of zero is returned.
+If a lock is associated with the callout given by the
+.Fa c
+argument and it is exclusivly locked when this function is called, this
+function will always ensure that previous callback function, if any,
+is never reached.
+In other words, the callout will be atomically restarted.
+Otherwise, there is no such guarantee.
+The callback function is given by
+.Fa func
+and its function argument is given by
+.Fa arg .
+.Pp
+.Ft int
+.Fn callout_reset_curcpu "struct callout *c" "int ticks" "callout_func_t *func" \
+"void *arg"
+This function works the same like the
+.Fn callout_reset
+function except the callback function given by the
+.Fa func
+argument will be executed on the same CPU which called this function.
+.Pp
+.Ft int
+.Fn callout_reset_on "struct callout *c" "int ticks" "callout_func_t *func" \
+"void *arg" "int cpu"
+This function works the same like the
+.Fn callout_reset
+function except the callback function given by the
+.Fa func
+argument will be executed on the CPU given by the
+.Fa cpu
+argument.
+.Pp
+.Ft int
+.Fn callout_reset_sbt "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "callout_func_t *func" "void *arg" "int flags"
+This function works the same like the
+.Fn callout_reset
+function except the relative or absolute time after which the timeout
+callback should happen is given by the
.Fa sbt
-and extends for the amount of time specified in
+argument and extends for the amount of time specified in
.Fa pr .
+This function is used when high precision timeouts are needed.
If
.Fa sbt
specifies a time in the past,
@@ -322,12 +301,13 @@
allows the callout subsystem to coalesce callouts scheduled close to each
other into fewer timer interrupts,
reducing processing overhead and power consumption.
-These
+The
.Fa flags
-may be specified to adjust the interpretation of
+argument may be non-zero to adjust the interpretation of the
.Fa sbt
and
-.Fa pr :
+.Fa pr
+arguments:
.Bl -tag -width ".Dv C_DIRECT_EXEC"
.It Dv C_ABSOLUTE
Handle the
@@ -347,7 +327,7 @@
and should be as small as possible because they run with absolute priority.
.It Fn C_PREL
Specifies relative event time precision as binary logarithm of time interval
-divided by acceptable time deviation: 1 -- 1/2, 2 -- 1/4, etc.
+divided by acceptable time deviation: 1 -- 1/2, 2 -- 1/4, and so on.
Note that the larger of
.Fa pr
or this value is used as the length of the time window.
@@ -360,65 +340,207 @@
calls if possible.
.El
.Pp
-The
-.Fn callout_reset
-functions accept a
+.Ft int
+.Fn callout_reset_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "callout_func_t *func" "void *arg" "int flags"
+This function works like
+.Fn callout_reset_sbt ,
+except the callback function given by the
.Fa func
-argument which identifies the function to be called when the time expires.
-It must be a pointer to a function that takes a single
-.Fa void *
-argument.
-Upon invocation,
+argument will be executed on the CPU which called this function.
+.Pp
+.Ft int
+.Fn callout_reset_sbt_on "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "callout_func_t *func" "void *arg" "int cpu" "int flags"
+This function works like
+.Fn callout_reset_sbt ,
+except the callback function given by
.Fa func
-will receive
-.Fa arg
-as its only argument.
-The
-.Fn callout_schedule
-functions reuse the
+will be executed on the CPU given by
+.Fa cpu .
+.Pp
+.Ft int
+.Fn callout_schedule "struct callout *c" "int ticks"
+This function works the same like the
+.Fn callout_reset
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_curcpu "struct callout *c" "int ticks"
+This function works the same like the
+.Fn callout_reset_curcpu
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_on "struct callout *c" "int ticks" "int cpu"
+This function works the same like the
+.Fn callout_reset_on
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_sbt "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "int flags"
+This function works the same like the
+.Fn callout_reset_sbt
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "int flags"
+This function works the same like the
+.Fn callout_reset_sbt_curcpu
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_sbt_on "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "int cpu" "int flags"
+This function works the same like the
+.Fn callout_reset_sbt_on
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Sh CHECKING THE STATE OF CALLOUTS
+.Ft int
+.Fn callout_pending "struct callout *c"
+This function returns non-zero if the callout pointed to by the
+.Fa c
+argument is pending for callback.
+Else this function returns zero.
+This function returns zero when inside the callout function if the
+callout is not re-scheduled.
+.Pp
+.Ft int
+.Fn callout_active "struct callout *c"
+This function is deprecated and returns non-zero if the callout
+pointed to by the
+.Fa c
+argument was scheduled in the past.
+Else this function returns zero.
+This function also returns zero after the
+.Fn callout_deactivate
+or the
+.Fn callout_stop
+or the
+.Fn callout_drain
+or the
+.Fn callout_drain_async
+function is called on the same callout as given by the
+.Fa c
+argument.
+.Pp
+.Ft void
+.Fn callout_deactivate "struct callout *c"
+This function is deprecated and ensures that subsequent calls to the
+.Fn callout_activate
+function returns zero until the callout is scheduled again.
+.Sh STOPPING CALLOUTS
+.Ft void
+.Fn untimeout "timeout_t *func" "void *arg" "struct callout_handle handle"
+This function is deprecated and cancels the timeout associated with the
+.Fa handle
+argument using the function pointed to by the
.Fa func
-and
+argument and having the
.Fa arg
-arguments from the previous callout.
-Note that one of the
-.Fn callout_reset
-functions must always be called to initialize
+arguments to validate the handle.
+If the handle does not correspond to a timeout with
+the function
.Fa func
-and
+taking the argument
.Fa arg
-before one of the
-.Fn callout_schedule
-functions can be used.
+no action is taken. The
+.Fa handle
+must be initialized by a previous call to
+.Fn timeout ,
+.Fn callout_handle_init
+or assigned the value of
+.Fn CALLOUT_HANDLE_INITIALIZER "&handle"
+before being passed to
+.Fn untimeout .
+The behavior of calling
+.Fn untimeout
+with an uninitialized handle
+is undefined.
.Pp
-The callout subsystem provides a softclock thread for each CPU in the system.
-Callouts are assigned to a single CPU and are executed by the softclock thread
-for that CPU.
-Initially,
-callouts are assigned to CPU 0.
-The
-.Fn callout_reset_on ,
-.Fn callout_reset_sbt_on ,
-.Fn callout_schedule_on
-and
-.Fn callout_schedule_sbt_on
-functions assign the callout to CPU
-.Fa cpu .
-The
-.Fn callout_reset_curcpu ,
-.Fn callout_reset_sbt_curpu ,
-.Fn callout_schedule_curcpu
-and
-.Fn callout_schedule_sbt_curcpu
-functions assign the callout to the current CPU.
-The
-.Fn callout_reset ,
-.Fn callout_reset_sbt ,
-.Fn callout_schedule
-and
-.Fn callout_schedule_sbt
-functions schedule the callout to execute in the softclock thread of the CPU
-to which it is currently assigned.
+.Ft int
+.Fn callout_stop "struct callout *c"
+This function is used to stop a timeout function invocation associated with the callout pointed to by the
+.Fa c
+argument, in a non-blocking fashion.
+This function can be called multiple times in a row with no side effects, even if the callout is already stopped. This function however should not be called before the callout has been initialized.
+This function returns a non-zero value if the given callout was pending and
+the callback function was prevented from being called.
+Else a value of zero is returned.
+If a lock is associated with the callout given by the
+.Fa c
+argument and it is exclusivly locked when this function is called, the
+.Fn callout_stop
+function will always ensure that the callback function is never reached.
+In other words the callout will be atomically stopped.
+Else there is no such guarantee.
+.Sh DRAINING CALLOUTS
+.Ft int
+.Fn callout_drain "struct callout *c"
+This function works the same like the
+.Fn callout_stop
+function except it ensures that all callback functions have returned and there are no more references to the callout pointed to by the
+.Fa c
+argument inside the callout subsystem before it returns.
+Also this function ensures that the lock, if any, associated with the
+callout is no longer being used.
+When this function returns, it is safe to free the callout structure pointed to by the
+.Fa c
+argument.
.Pp
+.Ft int
+.Fn callout_drain_async "struct callout *c" "callout_func_t *fn" "void *arg"
+This function is non-blocking and works the same like the
+.Fn callout_stop
+function except if it returns non-zero it means the callback function pointed to by the
+.Fa fn
+argument will be called back with the
+.Fa arg
+argument when all references to the callout pointed to by the
+.Fa c
+argument are gone.
+If this function returns non-zero it should not be called again until the callback function has been called.
+If the
+.Fn callout_drain
+or
+.Fn callout_drain_async
+functions are called while an asynchronous drain is pending,
+previously pending asynchronous drains might get cancelled.
+If this function returns zero, it is safe to free the callout structure pointed to by the
+.Fa c
+argument right away.
+.Sh CALLOUT FUNCTION RESTRICTIONS
+Callout functions must not sleep.
+They may not acquire sleepable locks, wait on condition variables,
+perform blocking allocation requests, or invoke any other action that
+might sleep.
+.Sh CALLOUT SUBSYSTEM INTERNALS
+The callout subsystem has its own set of spinlocks to protect its internal state.
+The callout subsystem provides a softclock thread for each CPU in the
+system.
+Callouts are assigned to a single CPU and are executed by the
+softclock thread for that CPU.
+Initially, callouts are assigned to CPU 0.
Softclock threads are not pinned to their respective CPUs by default.
The softclock thread for CPU 0 can be pinned to CPU 0 by setting the
.Va kern.pin_default_swi
@@ -427,50 +549,7 @@
respective CPUs by setting the
.Va kern.pin_pcpu_swi
loader tunable to a non-zero value.
-.Pp
-The macros
-.Fn callout_pending ,
-.Fn callout_active
-and
-.Fn callout_deactivate
-provide access to the current state of the callout.
-The
-.Fn callout_pending
-macro checks whether a callout is
-.Em pending ;
-a callout is considered
-.Em pending
-when a timeout has been set but the time has not yet arrived.
-Note that once the timeout time arrives and the callout subsystem
-starts to process this callout,
-.Fn callout_pending
-will return
-.Dv FALSE
-even though the callout function may not have finished
-.Pq or even begun
-executing.
-The
-.Fn callout_active
-macro checks whether a callout is marked as
-.Em active ,
-and the
-.Fn callout_deactivate
-macro clears the callout's
-.Em active
-flag.
-The callout subsystem marks a callout as
-.Em active
-when a timeout is set and it clears the
-.Em active
-flag in
-.Fn callout_stop
-and
-.Fn callout_drain ,
-but it
-.Em does not
-clear it when a callout expires normally via the execution of the
-callout function.
-.Ss "Avoiding Race Conditions"
+.Sh "AVOIDING RACE CONDITIONS"
The callout subsystem invokes callout functions from its own thread
context.
Without some kind of synchronization,
@@ -531,9 +610,8 @@
.Pc
indicates whether or not the callout was removed.
If it is known that the callout was set and the callout function has
-not yet executed, then a return value of
-.Dv FALSE
-indicates that the callout function is about to be called.
+not yet executed, then a return value of zero indicates that the
+callout function is about to be called.
For example:
.Bd -literal -offset indent
if (sc->sc_flags & SCFLG_CALLOUT_RUNNING) {
@@ -589,16 +667,14 @@
.Em pending
flag and return without action if
.Fn callout_pending
-returns
-.Dv TRUE .
+returns non-zero.
This indicates that the callout was rescheduled using
.Fn callout_reset
just before the callout function was invoked.
If
.Fn callout_active
-returns
-.Dv FALSE
-then the callout function should also return without action.
+returns zero then the callout function should also return without
+action.
This indicates that the callout has been stopped.
Finally, the callout function should call
.Fn callout_deactivate
@@ -668,129 +744,13 @@
or releasing the storage for the callout structure.
.Sh LEGACY API
.Bf Sy
-The functions below are a legacy API that will be removed in a future release.
-New code should not use these routines.
-.Ef
-.Pp
-The function
-.Fn timeout
-schedules a call to the function given by the argument
-.Fa func
-to take place after
-.Fa ticks Ns No /hz
-seconds.
-Non-positive values of
-.Fa ticks
-are silently converted to the value
-.Sq 1 .
-.Fa func
-should be a pointer to a function that takes a
-.Fa void *
-argument.
-Upon invocation,
-.Fa func
-will receive
-.Fa arg
-as its only argument.
-The return value from
+The
.Fn timeout
-is a
-.Ft struct callout_handle
-which can be used in conjunction with the
-.Fn untimeout
-function to request that a scheduled timeout be canceled.
-.Pp
-The function
-.Fn callout_handle_init
-can be used to initialize a handle to a state which will cause
-any calls to
-.Fn untimeout
-with that handle to return with no side
-effects.
-.Pp
-Assigning a callout handle the value of
-.Fn CALLOUT_HANDLE_INITIALIZER
-performs the same function as
-.Fn callout_handle_init
-and is provided for use on statically declared or global callout handles.
-.Pp
-The function
-.Fn untimeout
-cancels the timeout associated with
-.Fa handle
-using the
-.Fa func
and
-.Fa arg
-arguments to validate the handle.
-If the handle does not correspond to a timeout with
-the function
-.Fa func
-taking the argument
-.Fa arg
-no action is taken.
-.Fa handle
-must be initialized by a previous call to
-.Fn timeout ,
-.Fn callout_handle_init ,
-or assigned the value of
-.Fn CALLOUT_HANDLE_INITIALIZER "&handle"
-before being passed to
-.Fn untimeout .
-The behavior of calling
.Fn untimeout
-with an uninitialized handle
-is undefined.
-.Pp
-As handles are recycled by the system, it is possible (although unlikely)
-that a handle from one invocation of
-.Fn timeout
-may match the handle of another invocation of
-.Fn timeout
-if both calls used the same function pointer and argument, and the first
-timeout is expired or canceled before the second call.
-The timeout facility offers O(1) running time for
-.Fn timeout
-and
-.Fn untimeout .
-Timeouts are executed from
-.Fn softclock
-with the
-.Va Giant
-lock held.
-Thus they are protected from re-entrancy.
-.Sh RETURN VALUES
-The
-.Fn callout_active
-macro returns the state of a callout's
-.Em active
-flag.
-.Pp
-The
-.Fn callout_pending
-macro returns the state of a callout's
-.Em pending
-flag.
-.Pp
-The
-.Fn callout_reset
-and
-.Fn callout_schedule
-function families return non-zero if the callout was pending before the new
-function invocation was scheduled.
-.Pp
-The
-.Fn callout_stop
-and
-.Fn callout_drain
-functions return non-zero if the callout was still pending when it was
-called or zero otherwise.
-The
-.Fn timeout
-function returns a
-.Ft struct callout_handle
-that can be passed to
-.Fn untimeout .
+functions are a legacy API that will be removed in a future release.
+New code should not use these routines.
+.Ef
.Sh HISTORY
The current timeout and untimeout routines are based on the work of
.An Adam M. Costello
@@ -815,4 +775,4 @@
.Bx
linked list
callout mechanism which offered O(n) insertion and removal running time
-but did not generate or require handles for untimeout operations.
+and did not generate or require handles for untimeout operations.
Index: projects/hps_head/sys/kern/init_main.c
===================================================================
--- projects/hps_head/sys/kern/init_main.c
+++ projects/hps_head/sys/kern/init_main.c
@@ -506,7 +506,8 @@
callout_init_mtx(&p->p_itcallout, &p->p_mtx, 0);
callout_init_mtx(&p->p_limco, &p->p_mtx, 0);
- callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
+ mtx_init(&td->td_slpmutex, "td_slpmutex", NULL, MTX_SPIN);
+ callout_init_mtx(&td->td_slpcallout, &td->td_slpmutex, 0);
/* Create credentials. */
newcred = crget();
Index: projects/hps_head/sys/kern/kern_clocksource.c
===================================================================
--- projects/hps_head/sys/kern/kern_clocksource.c
+++ projects/hps_head/sys/kern/kern_clocksource.c
@@ -160,6 +160,9 @@
int usermode;
int done, runs;
+ KASSERT(curthread->td_critnest != 0,
+ ("Must be in a critical section"));
+
CTR3(KTR_SPARE2, "handle at %d: now %d.%08x",
curcpu, (int)(now >> 32), (u_int)(now & 0xffffffff));
done = 0;
Index: projects/hps_head/sys/kern/kern_condvar.c
===================================================================
--- projects/hps_head/sys/kern/kern_condvar.c
+++ projects/hps_head/sys/kern/kern_condvar.c
@@ -313,15 +313,13 @@
DROP_GIANT();
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0);
+ sleepq_release(cvp);
sleepq_set_timeout_sbt(cvp, sbt, pr, flags);
if (lock != &Giant.lock_object) {
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_release(cvp);
WITNESS_SAVE(lock, lock_witness);
lock_state = class->lc_unlock(lock);
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_lock(cvp);
}
+ sleepq_lock(cvp);
rval = sleepq_timedwait(cvp, 0);
#ifdef KTRACE
@@ -383,15 +381,13 @@
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR |
SLEEPQ_INTERRUPTIBLE, 0);
+ sleepq_release(cvp);
sleepq_set_timeout_sbt(cvp, sbt, pr, flags);
if (lock != &Giant.lock_object) {
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_release(cvp);
WITNESS_SAVE(lock, lock_witness);
lock_state = class->lc_unlock(lock);
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_lock(cvp);
}
+ sleepq_lock(cvp);
rval = sleepq_timedwait_sig(cvp, 0);
#ifdef KTRACE
Index: projects/hps_head/sys/kern/kern_lock.c
===================================================================
--- projects/hps_head/sys/kern/kern_lock.c
+++ projects/hps_head/sys/kern/kern_lock.c
@@ -210,9 +210,11 @@
GIANT_SAVE();
sleepq_add(&lk->lock_object, NULL, wmesg, SLEEPQ_LK | (catch ?
SLEEPQ_INTERRUPTIBLE : 0), queue);
- if ((flags & LK_TIMELOCK) && timo)
+ if ((flags & LK_TIMELOCK) && timo) {
+ sleepq_release(&lk->lock_object);
sleepq_set_timeout(&lk->lock_object, timo);
-
+ sleepq_lock(&lk->lock_object);
+ }
/*
* Decisional switch for real sleeping.
*/
Index: projects/hps_head/sys/kern/kern_switch.c
===================================================================
--- projects/hps_head/sys/kern/kern_switch.c
+++ projects/hps_head/sys/kern/kern_switch.c
@@ -93,8 +93,6 @@
&DPCPU_NAME(sched_switch_stats[SWT_TURNSTILE]), "");
SCHED_STAT_DEFINE_VAR(sleepq,
&DPCPU_NAME(sched_switch_stats[SWT_SLEEPQ]), "");
-SCHED_STAT_DEFINE_VAR(sleepqtimo,
- &DPCPU_NAME(sched_switch_stats[SWT_SLEEPQTIMO]), "");
SCHED_STAT_DEFINE_VAR(relinquish,
&DPCPU_NAME(sched_switch_stats[SWT_RELINQUISH]), "");
SCHED_STAT_DEFINE_VAR(needresched,
Index: projects/hps_head/sys/kern/kern_synch.c
===================================================================
--- projects/hps_head/sys/kern/kern_synch.c
+++ projects/hps_head/sys/kern/kern_synch.c
@@ -219,12 +219,16 @@
* return from cursig().
*/
sleepq_add(ident, lock, wmesg, sleepq_flags, 0);
- if (sbt != 0)
- sleepq_set_timeout_sbt(ident, sbt, pr, flags);
if (lock != NULL && class->lc_flags & LC_SLEEPABLE) {
sleepq_release(ident);
WITNESS_SAVE(lock, lock_witness);
lock_state = class->lc_unlock(lock);
+ if (sbt != 0)
+ sleepq_set_timeout_sbt(ident, sbt, pr, flags);
+ sleepq_lock(ident);
+ } else if (sbt != 0) {
+ sleepq_release(ident);
+ sleepq_set_timeout_sbt(ident, sbt, pr, flags);
sleepq_lock(ident);
}
if (sbt != 0 && catch)
@@ -289,8 +293,11 @@
* We put ourselves on the sleep queue and start our timeout.
*/
sleepq_add(ident, &mtx->lock_object, wmesg, SLEEPQ_SLEEP, 0);
- if (sbt != 0)
+ if (sbt != 0) {
+ sleepq_release(ident);
sleepq_set_timeout_sbt(ident, sbt, pr, flags);
+ sleepq_lock(ident);
+ }
/*
* Can't call ktrace with any spin locks held so it can lock the
Index: projects/hps_head/sys/kern/kern_thread.c
===================================================================
--- projects/hps_head/sys/kern/kern_thread.c
+++ projects/hps_head/sys/kern/kern_thread.c
@@ -149,6 +149,9 @@
audit_thread_alloc(td);
#endif
umtx_thread_alloc(td);
+
+ mtx_init(&td->td_slpmutex, "td_slpmutex", NULL, MTX_SPIN);
+ callout_init_mtx(&td->td_slpcallout, &td->td_slpmutex, 0);
return (0);
}
@@ -162,6 +165,10 @@
td = (struct thread *)mem;
+ /* make sure to drain any use of the "td->td_slpcallout" */
+ callout_drain(&td->td_slpcallout);
+ mtx_destroy(&td->td_slpmutex);
+
#ifdef INVARIANTS
/* Verify that this thread is in a safe state to free. */
switch (td->td_state) {
@@ -544,7 +551,6 @@
LIST_INIT(&td->td_lprof[0]);
LIST_INIT(&td->td_lprof[1]);
sigqueue_init(&td->td_sigqueue, p);
- callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
TAILQ_INSERT_TAIL(&p->p_threads, td, td_plist);
p->p_numthreads++;
}
Index: projects/hps_head/sys/kern/kern_timeout.c
===================================================================
--- projects/hps_head/sys/kern/kern_timeout.c
+++ projects/hps_head/sys/kern/kern_timeout.c
@@ -54,6 +54,8 @@
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
+#include <sys/rmlock.h>
+#include <sys/rwlock.h>
#include <sys/proc.h>
#include <sys/sdt.h>
#include <sys/sleepqueue.h>
@@ -75,28 +77,25 @@
"struct callout *");
#ifdef CALLOUT_PROFILING
-static int avg_depth;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
+static int avg_depth[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth[0], 0,
"Average number of items examined per softclock call. Units = 1/1000");
-static int avg_gcalls;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
+static int avg_gcalls[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls[0], 0,
"Average number of Giant callouts made per softclock call. Units = 1/1000");
-static int avg_lockcalls;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0,
+static int avg_lockcalls[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls[0], 0,
"Average number of lock callouts made per softclock call. Units = 1/1000");
-static int avg_mpcalls;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
+static int avg_mpcalls[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls[0], 0,
"Average number of MP callouts made per softclock call. Units = 1/1000");
-static int avg_depth_dir;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0,
+SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth[1], 0,
"Average number of direct callouts examined per callout_process call. "
"Units = 1/1000");
-static int avg_lockcalls_dir;
SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD,
- &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per "
+ &avg_lockcalls[1], 0, "Average number of lock direct callouts made per "
"callout_process call. Units = 1/1000");
-static int avg_mpcalls_dir;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir,
+SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls[1],
0, "Average number of MP direct callouts made per callout_process call. "
"Units = 1/1000");
#endif
@@ -124,64 +123,230 @@
*/
u_int callwheelsize, callwheelmask;
+#define CALLOUT_RET_NORMAL 0
+#define CALLOUT_RET_CANCELLED 1
+#define CALLOUT_RET_DRAINING 2
+
+struct callout_args {
+ sbintime_t time; /* absolute time for the event */
+ sbintime_t precision; /* delta allowed wrt opt */
+ void *arg; /* function argument */
+ callout_func_t *func; /* function to call */
+ int flags; /* flags passed to callout_reset() */
+ int cpu; /* CPU we're scheduled on */
+};
+
+typedef void callout_mutex_op_t(struct lock_object *);
+
+struct callout_mutex_ops {
+ callout_mutex_op_t *lock;
+ callout_mutex_op_t *unlock;
+};
+
+enum {
+ CALLOUT_LC_UNUSED_0,
+ CALLOUT_LC_UNUSED_1,
+ CALLOUT_LC_UNUSED_2,
+ CALLOUT_LC_UNUSED_3,
+ CALLOUT_LC_SPIN,
+ CALLOUT_LC_MUTEX,
+ CALLOUT_LC_RW,
+ CALLOUT_LC_RM,
+};
+
+static void
+callout_mutex_op_none(struct lock_object *lock)
+{
+}
+
+static void
+callout_mutex_lock(struct lock_object *lock)
+{
+
+ mtx_lock((struct mtx *)lock);
+}
+
+static void
+callout_mutex_unlock(struct lock_object *lock)
+{
+
+ mtx_unlock((struct mtx *)lock);
+}
+
+static void
+callout_mutex_lock_spin(struct lock_object *lock)
+{
+
+ mtx_lock_spin((struct mtx *)lock);
+}
+
+static void
+callout_mutex_unlock_spin(struct lock_object *lock)
+{
+
+ mtx_unlock_spin((struct mtx *)lock);
+}
+
+static void
+callout_rm_wlock(struct lock_object *lock)
+{
+
+ rm_wlock((struct rmlock *)lock);
+}
+
+static void
+callout_rm_wunlock(struct lock_object *lock)
+{
+
+ rm_wunlock((struct rmlock *)lock);
+}
+
+static void
+callout_rw_wlock(struct lock_object *lock)
+{
+
+ rw_wlock((struct rwlock *)lock);
+}
+
+static void
+callout_rw_wunlock(struct lock_object *lock)
+{
+
+ rw_wunlock((struct rwlock *)lock);
+}
+
+static const struct callout_mutex_ops callout_mutex_ops[8] = {
+ [CALLOUT_LC_UNUSED_0] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ },
+ [CALLOUT_LC_UNUSED_1] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ },
+ [CALLOUT_LC_UNUSED_2] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ },
+ [CALLOUT_LC_UNUSED_3] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ },
+ [CALLOUT_LC_SPIN] = {
+ .lock = callout_mutex_lock_spin,
+ .unlock = callout_mutex_unlock_spin,
+ },
+ [CALLOUT_LC_MUTEX] = {
+ .lock = callout_mutex_lock,
+ .unlock = callout_mutex_unlock,
+ },
+ [CALLOUT_LC_RW] = {
+ .lock = callout_rw_wlock,
+ .unlock = callout_rw_wunlock,
+ },
+ [CALLOUT_LC_RM] = {
+ .lock = callout_rm_wlock,
+ .unlock = callout_rm_wunlock,
+ },
+};
+
+static inline void
+callout_lock_client(int c_flags, struct lock_object *c_lock)
+{
+
+ callout_mutex_ops[CALLOUT_GET_LC(c_flags)].lock(c_lock);
+}
+
+static inline void
+callout_unlock_client(int c_flags, struct lock_object *c_lock)
+{
+
+ callout_mutex_ops[CALLOUT_GET_LC(c_flags)].unlock(c_lock);
+}
+
/*
- * The callout cpu exec entities represent informations necessary for
- * describing the state of callouts currently running on the CPU and the ones
- * necessary for migrating callouts to the new callout cpu. In particular,
- * the first entry of the array cc_exec_entity holds informations for callout
- * running in SWI thread context, while the second one holds informations
- * for callout running directly from hardware interrupt context.
- * The cached informations are very important for deferring migration when
- * the migrating callout is already running.
+ * The callout CPU exec structure represent information necessary for
+ * describing the state of callouts currently running on the CPU and
+ * for handling deferred callout restarts.
+ *
+ * In particular, the first entry of the array cc_exec_entity holds
+ * information for callouts running from the SWI thread context, while
+ * the second one holds information for callouts running directly from
+ * the hardware interrupt context.
*/
struct cc_exec {
+ /*
+ * The "cc_curr" points to the currently executing callout and
+ * is protected by the "cc_lock" spinlock. If no callback is
+ * currently executing it is equal to "NULL".
+ */
struct callout *cc_curr;
-#ifdef SMP
- void (*ce_migration_func)(void *);
- void *ce_migration_arg;
- int ce_migration_cpu;
- sbintime_t ce_migration_time;
- sbintime_t ce_migration_prec;
+ /*
+ * The "cc_restart_args" structure holds the argument for a
+ * deferred callback restart and is protected by the "cc_lock"
+ * spinlock. The structure is only valid if "cc_restart" is
+ * "true". If "cc_restart" is "false" the information in the
+ * "cc_restart_args" structure shall be ignored.
+ */
+ struct callout_args cc_restart_args;
+ bool cc_restart;
+ /*
+ * The "cc_cancel" variable allows the currently pending
+ * callback to be atomically cancelled. This field is write
+ * protected by the "cc_lock" spinlock.
+ */
+ bool cc_cancel;
+ /*
+ * The "cc_drain_fn" points to a function which shall be
+ * called with the argument stored in "cc_drain_arg" when an
+ * asynchronous drain is performed. This field is write
+ * protected by the "cc_lock" spinlock.
+ */
+ callout_func_t *cc_drain_fn;
+ void *cc_drain_arg;
+ /*
+ * The following fields are used for callout profiling only:
+ */
+#ifdef CALLOUT_PROFILING
+ int cc_depth;
+ int cc_mpcalls;
+ int cc_lockcalls;
+ int cc_gcalls;
#endif
- bool cc_cancel;
- bool cc_waiting;
};
/*
- * There is one struct callout_cpu per cpu, holding all relevant
+ * There is one "struct callout_cpu" per CPU, holding all relevant
* state for the callout processing thread on the individual CPU.
*/
struct callout_cpu {
struct mtx_padalign cc_lock;
struct cc_exec cc_exec_entity[2];
- struct callout *cc_next;
struct callout *cc_callout;
struct callout_list *cc_callwheel;
+ struct callout_list cc_tmplist;
struct callout_tailq cc_expireq;
struct callout_slist cc_callfree;
sbintime_t cc_firstevent;
sbintime_t cc_lastscan;
void *cc_cookie;
- u_int cc_bucket;
- u_int cc_inited;
char cc_ktr_event_name[20];
};
-#define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION)
+#define cc_exec_curr(cc, dir) (cc)->cc_exec_entity[(dir)].cc_curr
+#define cc_exec_restart_args(cc, dir) (cc)->cc_exec_entity[(dir)].cc_restart_args
+#define cc_exec_restart(cc, dir) (cc)->cc_exec_entity[(dir)].cc_restart
+#define cc_exec_cancel(cc, dir) (cc)->cc_exec_entity[(dir)].cc_cancel
+#define cc_exec_drain_fn(cc, dir) (cc)->cc_exec_entity[(dir)].cc_drain_fn
+#define cc_exec_drain_arg(cc, dir) (cc)->cc_exec_entity[(dir)].cc_drain_arg
+#define cc_exec_depth(cc, dir) (cc)->cc_exec_entity[(dir)].cc_depth
+#define cc_exec_mpcalls(cc, dir) (cc)->cc_exec_entity[(dir)].cc_mpcalls
+#define cc_exec_lockcalls(cc, dir) (cc)->cc_exec_entity[(dir)].cc_lockcalls
+#define cc_exec_gcalls(cc, dir) (cc)->cc_exec_entity[(dir)].cc_gcalls
-#define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr
-#define cc_exec_next(cc) cc->cc_next
-#define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel
-#define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting
#ifdef SMP
-#define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func
-#define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg
-#define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu
-#define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time
-#define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec
-
struct callout_cpu cc_cpu[MAXCPU];
-#define CPUBLOCK MAXCPU
+#define CPUBLOCK -1
#define CC_CPU(cpu) (&cc_cpu[(cpu)])
#define CC_SELF() CC_CPU(PCPU_GET(cpuid))
#else
@@ -196,67 +361,13 @@
static int timeout_cpu;
static void callout_cpu_init(struct callout_cpu *cc, int cpu);
-static void softclock_call_cc(struct callout *c, struct callout_cpu *cc,
-#ifdef CALLOUT_PROFILING
- int *mpcalls, int *lockcalls, int *gcalls,
-#endif
- int direct);
+static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, const int direct);
static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures");
-/**
- * Locked by cc_lock:
- * cc_curr - If a callout is in progress, it is cc_curr.
- * If cc_curr is non-NULL, threads waiting in
- * callout_drain() will be woken up as soon as the
- * relevant callout completes.
- * cc_cancel - Changing to 1 with both callout_lock and cc_lock held
- * guarantees that the current callout will not run.
- * The softclock() function sets this to 0 before it
- * drops callout_lock to acquire c_lock, and it calls
- * the handler only if curr_cancelled is still 0 after
- * cc_lock is successfully acquired.
- * cc_waiting - If a thread is waiting in callout_drain(), then
- * callout_wait is nonzero. Set only when
- * cc_curr is non-NULL.
- */
-
-/*
- * Resets the execution entity tied to a specific callout cpu.
- */
-static void
-cc_cce_cleanup(struct callout_cpu *cc, int direct)
-{
-
- cc_exec_curr(cc, direct) = NULL;
- cc_exec_cancel(cc, direct) = false;
- cc_exec_waiting(cc, direct) = false;
-#ifdef SMP
- cc_migration_cpu(cc, direct) = CPUBLOCK;
- cc_migration_time(cc, direct) = 0;
- cc_migration_prec(cc, direct) = 0;
- cc_migration_func(cc, direct) = NULL;
- cc_migration_arg(cc, direct) = NULL;
-#endif
-}
-
-/*
- * Checks if migration is requested by a specific callout cpu.
- */
-static int
-cc_cce_migrating(struct callout_cpu *cc, int direct)
-{
-
-#ifdef SMP
- return (cc_migration_cpu(cc, direct) != CPUBLOCK);
-#else
- return (0);
-#endif
-}
-
/*
- * Kernel low level callwheel initialization
- * called on cpu0 during kernel startup.
+ * Kernel low level callwheel initialization called from cpu0 during
+ * kernel startup:
*/
static void
callout_callwheel_init(void *dummy)
@@ -311,15 +422,13 @@
mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE);
SLIST_INIT(&cc->cc_callfree);
- cc->cc_inited = 1;
cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize,
M_CALLOUT, M_WAITOK);
for (i = 0; i < callwheelsize; i++)
LIST_INIT(&cc->cc_callwheel[i]);
TAILQ_INIT(&cc->cc_expireq);
+ LIST_INIT(&cc->cc_tmplist);
cc->cc_firstevent = SBT_MAX;
- for (i = 0; i < 2; i++)
- cc_cce_cleanup(cc, i);
snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name),
"callwheel cpu %d", cpu);
if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */
@@ -327,38 +436,38 @@
for (i = 0; i < ncallout; i++) {
c = &cc->cc_callout[i];
callout_init(c, 0);
- c->c_iflags = CALLOUT_LOCAL_ALLOC;
+ c->c_flags |= CALLOUT_LOCAL_ALLOC;
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
}
}
-#ifdef SMP
-/*
- * Switches the cpu tied to a specific callout.
- * The function expects a locked incoming callout cpu and returns with
- * locked outcoming callout cpu.
- */
-static struct callout_cpu *
-callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu)
+#ifdef CALLOUT_PROFILING
+static inline void
+callout_clear_stats(struct callout_cpu *cc, const int direct)
{
- struct callout_cpu *new_cc;
-
- MPASS(c != NULL && cc != NULL);
- CC_LOCK_ASSERT(cc);
+ cc_exec_depth(cc, direct) = 0;
+ cc_exec_mpcalls(cc, direct) = 0;
+ cc_exec_lockcalls(cc, direct) = 0;
+ cc_exec_gcalls(cc, direct) = 0;
+}
+#endif
- /*
- * Avoid interrupts and preemption firing after the callout cpu
- * is blocked in order to avoid deadlocks as the new thread
- * may be willing to acquire the callout cpu lock.
- */
- c->c_cpu = CPUBLOCK;
- spinlock_enter();
- CC_UNLOCK(cc);
- new_cc = CC_CPU(new_cpu);
- CC_LOCK(new_cc);
- spinlock_exit();
- c->c_cpu = new_cpu;
- return (new_cc);
+#ifdef CALLOUT_PROFILING
+static inline void
+callout_update_stats(struct callout_cpu *cc, const int direct)
+{
+ avg_depth[direct] +=
+ (cc_exec_depth(cc, direct) * 1000 -
+ avg_depth[direct]) >> 8;
+ avg_mpcalls[direct] +=
+ (cc_exec_mpcalls(cc, direct) * 1000 -
+ avg_mpcalls[direct]) >> 8;
+ avg_lockcalls[direct] +=
+ (cc_exec_lockcalls(cc, direct) * 1000 -
+ avg_lockcalls[direct]) >> 8;
+ avg_gcalls[direct] +=
+ (cc_exec_gcalls(cc, direct) * 1000 -
+ avg_gcalls[direct]) >> 8;
}
#endif
@@ -429,19 +538,19 @@
void
callout_process(sbintime_t now)
{
- struct callout *tmp, *tmpn;
+ struct callout *tmp;
struct callout_cpu *cc;
struct callout_list *sc;
sbintime_t first, last, max, tmp_max;
uint32_t lookahead;
u_int firstb, lastb, nowb;
-#ifdef CALLOUT_PROFILING
- int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0;
-#endif
cc = CC_SELF();
- mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET);
+ CC_LOCK(cc);
+#ifdef CALLOUT_PROFILING
+ callout_clear_stats(cc, 1);
+#endif
/* Compute the buckets of the last scan and present times. */
firstb = callout_hash(cc->cc_lastscan);
cc->cc_lastscan = now;
@@ -474,49 +583,44 @@
/* Iterate callwheel from firstb to nowb and then up to lastb. */
do {
sc = &cc->cc_callwheel[firstb & callwheelmask];
- tmp = LIST_FIRST(sc);
- while (tmp != NULL) {
+ while (1) {
+ tmp = LIST_FIRST(sc);
+ if (tmp == NULL)
+ break;
+
+ LIST_REMOVE(tmp, c_links.le);
+
/* Run the callout if present time within allowed. */
if (tmp->c_time <= now) {
/*
- * Consumer told us the callout may be run
- * directly from hardware interrupt context.
+ * Consumer told us the callout may be
+ * run directly from the hardware
+ * interrupt context:
*/
- if (tmp->c_iflags & CALLOUT_DIRECT) {
-#ifdef CALLOUT_PROFILING
- ++depth_dir;
-#endif
- cc_exec_next(cc) =
- LIST_NEXT(tmp, c_links.le);
- cc->cc_bucket = firstb & callwheelmask;
- LIST_REMOVE(tmp, c_links.le);
- softclock_call_cc(tmp, cc,
-#ifdef CALLOUT_PROFILING
- &mpcalls_dir, &lockcalls_dir, NULL,
-#endif
- 1);
- tmp = cc_exec_next(cc);
- cc_exec_next(cc) = NULL;
+ if (tmp->c_flags & CALLOUT_DIRECT) {
+ softclock_call_cc(tmp, cc, 1);
} else {
- tmpn = LIST_NEXT(tmp, c_links.le);
- LIST_REMOVE(tmp, c_links.le);
TAILQ_INSERT_TAIL(&cc->cc_expireq,
tmp, c_links.tqe);
- tmp->c_iflags |= CALLOUT_PROCESSED;
- tmp = tmpn;
+ tmp->c_flags |= CALLOUT_PROCESSED;
}
continue;
}
+
+ /* insert callout into temporary list */
+ LIST_INSERT_HEAD(&cc->cc_tmplist, tmp, c_links.le);
+
/* Skip events from distant future. */
if (tmp->c_time >= max)
- goto next;
+ continue;
+
/*
* Event minimal time is bigger than present maximal
* time, so it cannot be aggregated.
*/
if (tmp->c_time > last) {
lastb = nowb;
- goto next;
+ continue;
}
/* Update first and last time, respecting this event. */
if (tmp->c_time < first)
@@ -524,11 +628,14 @@
tmp_max = tmp->c_time + tmp->c_precision;
if (tmp_max < last)
last = tmp_max;
-next:
- tmp = LIST_NEXT(tmp, c_links.le);
}
+
+ /* Put temporary list back into the main bucket */
+ LIST_SWAP(sc, &cc->cc_tmplist, callout, c_links.le);
+
/* Proceed with the next bucket. */
firstb++;
+
/*
* Stop if we looked after present time and found
* some event we can't execute at now.
@@ -540,14 +647,13 @@
cpu_new_callout(curcpu, last, first);
#endif
#ifdef CALLOUT_PROFILING
- avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8;
- avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8;
- avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8;
+ callout_update_stats(cc, 1);
#endif
- mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET);
+ CC_UNLOCK(cc);
/*
- * swi_sched acquires the thread lock, so we don't want to call it
- * with cc_lock held; incorrect locking order.
+ * "swi_sched()" acquires the thread lock and we don't want to
+ * call it having cc_lock held because it leads to a locking
+ * order reversal issue.
*/
if (!TAILQ_EMPTY(&cc->cc_expireq))
swi_sched(cc->cc_cookie, 0);
@@ -563,8 +669,7 @@
cpu = c->c_cpu;
#ifdef SMP
if (cpu == CPUBLOCK) {
- while (c->c_cpu == CPUBLOCK)
- cpu_spinwait();
+ cpu_spinwait();
continue;
}
#endif
@@ -577,32 +682,56 @@
return (cc);
}
-static void
-callout_cc_add(struct callout *c, struct callout_cpu *cc,
- sbintime_t sbt, sbintime_t precision, void (*func)(void *),
- void *arg, int cpu, int flags)
+static struct callout_cpu *
+callout_cc_add_locked(struct callout *c, struct callout_cpu *cc,
+ struct callout_args *coa)
{
- int bucket;
+#ifndef NO_EVENTTIMERS
+ sbintime_t sbt;
+#endif
+ u_int bucket;
CC_LOCK_ASSERT(cc);
- if (sbt < cc->cc_lastscan)
- sbt = cc->cc_lastscan;
- c->c_arg = arg;
- c->c_iflags |= CALLOUT_PENDING;
- c->c_iflags &= ~CALLOUT_PROCESSED;
- c->c_flags |= CALLOUT_ACTIVE;
- if (flags & C_DIRECT_EXEC)
- c->c_iflags |= CALLOUT_DIRECT;
- c->c_func = func;
- c->c_time = sbt;
- c->c_precision = precision;
+
+ /* update flags before swapping locks, if any */
+ c->c_flags &= ~(CALLOUT_PROCESSED | CALLOUT_DIRECT | CALLOUT_DEFRESTART);
+ if (coa->flags & C_DIRECT_EXEC)
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING | CALLOUT_DIRECT);
+ else
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
+
+#ifdef SMP
+ /* only set the "c_cpu" if the CPU number changed and is valid */
+ if (c->c_cpu != coa->cpu && coa->cpu > CPUBLOCK &&
+ coa->cpu <= mp_maxid && !CPU_ABSENT(coa->cpu)) {
+ /*
+ * Avoid interrupts and preemption firing after the
+ * callout CPU is blocked in order to avoid deadlocks
+ * as the new thread may be willing to acquire the
+ * callout CPU lock:
+ */
+ c->c_cpu = CPUBLOCK;
+ spinlock_enter();
+ CC_UNLOCK(cc);
+ cc = CC_CPU(coa->cpu);
+ CC_LOCK(cc);
+ spinlock_exit();
+ c->c_cpu = coa->cpu;
+ }
+#endif
+ if (coa->time < cc->cc_lastscan)
+ coa->time = cc->cc_lastscan;
+ c->c_arg = coa->arg;
+ c->c_func = coa->func;
+ c->c_time = coa->time;
+ c->c_precision = coa->precision;
+
bucket = callout_get_bucket(c->c_time);
CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x",
c, (int)(c->c_precision >> 32),
(u_int)(c->c_precision & 0xffffffff));
LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le);
- if (cc->cc_bucket == bucket)
- cc_exec_next(cc) = c;
+
#ifndef NO_EVENTTIMERS
/*
* Inform the eventtimers(4) subsystem there's a new callout
@@ -613,42 +742,28 @@
sbt = c->c_time + c->c_precision;
if (sbt < cc->cc_firstevent) {
cc->cc_firstevent = sbt;
- cpu_new_callout(cpu, sbt, c->c_time);
+ cpu_new_callout(c->c_cpu, sbt, c->c_time);
}
#endif
+ return (cc);
}
-static void
+static inline void
callout_cc_del(struct callout *c, struct callout_cpu *cc)
{
- if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0)
- return;
c->c_func = NULL;
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
}
-static void
+static inline void
softclock_call_cc(struct callout *c, struct callout_cpu *cc,
-#ifdef CALLOUT_PROFILING
- int *mpcalls, int *lockcalls, int *gcalls,
-#endif
- int direct)
+ const int direct)
{
- struct rm_priotracker tracker;
- void (*c_func)(void *);
+ callout_func_t *c_func;
void *c_arg;
- struct lock_class *class;
struct lock_object *c_lock;
- uintptr_t lock_status;
- int c_iflags;
-#ifdef SMP
- struct callout_cpu *new_cc;
- void (*new_func)(void *);
- void *new_arg;
- int flags, new_cpu;
- sbintime_t new_prec, new_time;
-#endif
+ int c_flags;
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
sbintime_t sbt1, sbt2;
struct timespec ts2;
@@ -656,62 +771,68 @@
static timeout_t *lastfunc;
#endif
- KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING,
- ("softclock_call_cc: pend %p %x", c, c->c_iflags));
- KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE,
- ("softclock_call_cc: act %p %x", c, c->c_flags));
- class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL;
- lock_status = 0;
- if (c->c_flags & CALLOUT_SHAREDLOCK) {
- if (class == &lock_class_rm)
- lock_status = (uintptr_t)&tracker;
- else
- lock_status = 1;
- }
+ KASSERT((c->c_flags & (CALLOUT_PENDING | CALLOUT_ACTIVE)) ==
+ (CALLOUT_PENDING | CALLOUT_ACTIVE),
+ ("softclock_call_cc: pend|act %p %x", c, c->c_flags));
+
c_lock = c->c_lock;
c_func = c->c_func;
c_arg = c->c_arg;
- c_iflags = c->c_iflags;
- if (c->c_iflags & CALLOUT_LOCAL_ALLOC)
- c->c_iflags = CALLOUT_LOCAL_ALLOC;
- else
- c->c_iflags &= ~CALLOUT_PENDING;
-
+ c_flags = c->c_flags;
+
+ /* remove pending bit */
+ c->c_flags &= ~CALLOUT_PENDING;
+
+ /* reset our local state */
cc_exec_curr(cc, direct) = c;
- cc_exec_cancel(cc, direct) = false;
- CC_UNLOCK(cc);
+ cc_exec_restart(cc, direct) = false;
+ cc_exec_drain_fn(cc, direct) = NULL;
+ cc_exec_drain_arg(cc, direct) = NULL;
+
if (c_lock != NULL) {
- class->lc_lock(c_lock, lock_status);
+ cc_exec_cancel(cc, direct) = false;
+ CC_UNLOCK(cc);
+
+ /* unlocked region for switching locks */
+
+ callout_lock_client(c_flags, c_lock);
+
/*
- * The callout may have been cancelled
- * while we switched locks.
+ * Check if the callout may have been cancelled while
+ * we were switching locks. Even though the callout is
+ * specifying a lock, it might not be certain this
+ * lock is locked when starting and stopping callouts.
*/
+ CC_LOCK(cc);
if (cc_exec_cancel(cc, direct)) {
- class->lc_unlock(c_lock);
- goto skip;
+ callout_unlock_client(c_flags, c_lock);
+ goto skip_cc_locked;
}
- /* The callout cannot be stopped now. */
- cc_exec_cancel(cc, direct) = true;
if (c_lock == &Giant.lock_object) {
#ifdef CALLOUT_PROFILING
- (*gcalls)++;
+ cc_exec_gcalls(cc, direct)++;
#endif
CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p",
c, c_func, c_arg);
} else {
#ifdef CALLOUT_PROFILING
- (*lockcalls)++;
+ cc_exec_lockcalls(cc, direct)++;
#endif
CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p",
c, c_func, c_arg);
}
} else {
#ifdef CALLOUT_PROFILING
- (*mpcalls)++;
+ cc_exec_mpcalls(cc, direct)++;
#endif
CTR3(KTR_CALLOUT, "callout %p func %p arg %p",
c, c_func, c_arg);
}
+ /* The callout cannot be stopped now! */
+ cc_exec_cancel(cc, direct) = true;
+ CC_UNLOCK(cc);
+
+ /* unlocked region */
KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running",
"func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct);
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
@@ -738,85 +859,46 @@
#endif
KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle");
CTR1(KTR_CALLOUT, "callout %p finished", c);
- if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0)
- class->lc_unlock(c_lock);
-skip:
+
+ /*
+ * At this point the callback structure might have been freed,
+ * so we need to check the previously copied value of
+ * "c->c_flags":
+ */
+ if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0)
+ callout_unlock_client(c_flags, c_lock);
+
CC_LOCK(cc);
+
+skip_cc_locked:
KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr"));
cc_exec_curr(cc, direct) = NULL;
- if (cc_exec_waiting(cc, direct)) {
+
+ /* Check if there is anything which needs draining */
+ if (cc_exec_drain_fn(cc, direct) != NULL) {
/*
- * There is someone waiting for the
- * callout to complete.
- * If the callout was scheduled for
- * migration just cancel it.
+ * Unlock the CPU callout last, so that any use of
+ * structures belonging to the callout are complete:
*/
- if (cc_cce_migrating(cc, direct)) {
- cc_cce_cleanup(cc, direct);
-
- /*
- * It should be assert here that the callout is not
- * destroyed but that is not easy.
- */
- c->c_iflags &= ~CALLOUT_DFRMIGRATION;
- }
- cc_exec_waiting(cc, direct) = false;
CC_UNLOCK(cc);
- wakeup(&cc_exec_waiting(cc, direct));
+ /* call drain function unlocked */
+ cc_exec_drain_fn(cc, direct)(
+ cc_exec_drain_arg(cc, direct));
CC_LOCK(cc);
- } else if (cc_cce_migrating(cc, direct)) {
- KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0,
- ("Migrating legacy callout %p", c));
-#ifdef SMP
- /*
- * If the callout was scheduled for
- * migration just perform it now.
- */
- new_cpu = cc_migration_cpu(cc, direct);
- new_time = cc_migration_time(cc, direct);
- new_prec = cc_migration_prec(cc, direct);
- new_func = cc_migration_func(cc, direct);
- new_arg = cc_migration_arg(cc, direct);
- cc_cce_cleanup(cc, direct);
-
- /*
- * It should be assert here that the callout is not destroyed
- * but that is not easy.
- *
- * As first thing, handle deferred callout stops.
- */
- if (!callout_migrating(c)) {
- CTR3(KTR_CALLOUT,
- "deferred cancelled %p func %p arg %p",
- c, new_func, new_arg);
- callout_cc_del(c, cc);
- return;
+ } else if (c_flags & CALLOUT_LOCAL_ALLOC) {
+ /* return callout back to freelist */
+ callout_cc_del(c, cc);
+ } else if (cc_exec_restart(cc, direct)) {
+ struct callout_cpu *new_cc;
+ /* [re-]schedule callout, if any */
+ new_cc = callout_cc_add_locked(c, cc,
+ &cc_exec_restart_args(cc, direct));
+ if (new_cc != cc) {
+ /* switch locks back again */
+ CC_UNLOCK(new_cc);
+ CC_LOCK(cc);
}
- c->c_iflags &= ~CALLOUT_DFRMIGRATION;
-
- new_cc = callout_cpu_switch(c, cc, new_cpu);
- flags = (direct) ? C_DIRECT_EXEC : 0;
- callout_cc_add(c, new_cc, new_time, new_prec, new_func,
- new_arg, new_cpu, flags);
- CC_UNLOCK(new_cc);
- CC_LOCK(cc);
-#else
- panic("migration should not happen");
-#endif
}
- /*
- * If the current callout is locally allocated (from
- * timeout(9)) then put it on the freelist.
- *
- * Note: we need to check the cached copy of c_iflags because
- * if it was not local, then it's not safe to deref the
- * callout pointer.
- */
- KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 ||
- c->c_iflags == CALLOUT_LOCAL_ALLOC,
- ("corrupted callout"));
- if (c_iflags & CALLOUT_LOCAL_ALLOC)
- callout_cc_del(c, cc);
}
/*
@@ -840,28 +922,18 @@
{
struct callout_cpu *cc;
struct callout *c;
-#ifdef CALLOUT_PROFILING
- int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0;
-#endif
cc = (struct callout_cpu *)arg;
CC_LOCK(cc);
- while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) {
- TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
- softclock_call_cc(c, cc,
#ifdef CALLOUT_PROFILING
- &mpcalls, &lockcalls, &gcalls,
-#endif
- 0);
-#ifdef CALLOUT_PROFILING
- ++depth;
+ callout_clear_stats(cc, 0);
#endif
+ while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) {
+ TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
+ softclock_call_cc(c, cc, 0);
}
#ifdef CALLOUT_PROFILING
- avg_depth += (depth * 1000 - avg_depth) >> 8;
- avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
- avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
- avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
+ callout_update_stats(cc, 0);
#endif
CC_UNLOCK(cc);
}
@@ -897,10 +969,11 @@
/* XXX Attempt to malloc first */
panic("timeout table full");
SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle);
- callout_reset(new, to_ticks, ftn, arg);
handle.callout = new;
CC_UNLOCK(cc);
+ callout_reset(new, to_ticks, ftn, arg);
+
return (handle);
}
@@ -908,6 +981,7 @@
untimeout(timeout_t *ftn, void *arg, struct callout_handle handle)
{
struct callout_cpu *cc;
+ bool match;
/*
* Check for a handle that was initialized
@@ -918,9 +992,11 @@
return;
cc = callout_lock(handle.callout);
- if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
- callout_stop(handle.callout);
+ match = (handle.callout->c_func == ftn && handle.callout->c_arg == arg);
CC_UNLOCK(cc);
+
+ if (match)
+ callout_stop(handle.callout);
}
void
@@ -929,6 +1005,118 @@
handle->callout = NULL;
}
+static int
+callout_restart_async(struct callout *c, struct callout_args *coa,
+ callout_func_t *drain_fn, void *drain_arg)
+{
+ struct callout_cpu *cc;
+ int cancelled;
+ int direct;
+
+ cc = callout_lock(c);
+
+ /* Figure out if the callout is direct or not */
+ direct = ((c->c_flags & CALLOUT_DIRECT) != 0);
+
+ /*
+ * Check if the callback is currently scheduled for
+ * completion:
+ */
+ if (cc_exec_curr(cc, direct) == c) {
+ /*
+ * Try to prevent the callback from running by setting
+ * the "cc_cancel" variable to "true". Also check if
+ * the callout was previously subject to a deferred
+ * callout restart:
+ */
+ if (cc_exec_cancel(cc, direct) == false ||
+ (c->c_flags & CALLOUT_DEFRESTART) != 0) {
+ cc_exec_cancel(cc, direct) = true;
+ cancelled = CALLOUT_RET_CANCELLED;
+ } else {
+ cancelled = CALLOUT_RET_NORMAL;
+ }
+
+ /*
+ * Prevent callback restart if "callout_drain_xxx()"
+ * is being called or we are stopping the callout or
+ * the callback was preallocated by us:
+ */
+ if (cc_exec_drain_fn(cc, direct) != NULL ||
+ coa == NULL || (c->c_flags & CALLOUT_LOCAL_ALLOC) != 0) {
+ CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
+ cancelled ? "cancelled and draining" : "draining",
+ c, c->c_func, c->c_arg);
+
+ /* clear old flags, if any */
+ c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING |
+ CALLOUT_DEFRESTART | CALLOUT_PROCESSED);
+
+ /* clear restart flag, if any */
+ cc_exec_restart(cc, direct) = false;
+
+ /* set drain function, if any */
+ if (drain_fn != NULL) {
+ cc_exec_drain_fn(cc, direct) = drain_fn;
+ cc_exec_drain_arg(cc, direct) = drain_arg;
+ cancelled |= CALLOUT_RET_DRAINING;
+ }
+ } else {
+ CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
+ cancelled ? "cancelled and restarting" : "restarting",
+ c, c->c_func, c->c_arg);
+
+ /* get us back into the game */
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING |
+ CALLOUT_DEFRESTART);
+ c->c_flags &= ~CALLOUT_PROCESSED;
+
+ /* enable deferred restart */
+ cc_exec_restart(cc, direct) = true;
+
+ /* store arguments for the deferred restart, if any */
+ cc_exec_restart_args(cc, direct) = *coa;
+ }
+ } else {
+ /* stop callout */
+ if (c->c_flags & CALLOUT_PENDING) {
+ /*
+ * The callback has not yet been executed, and
+ * we simply just need to unlink it:
+ */
+ if ((c->c_flags & CALLOUT_PROCESSED) == 0) {
+ LIST_REMOVE(c, c_links.le);
+ } else {
+ TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
+ }
+ cancelled = CALLOUT_RET_CANCELLED;
+ } else {
+ cancelled = CALLOUT_RET_NORMAL;
+ }
+
+ CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
+ cancelled ? "rescheduled" : "scheduled",
+ c, c->c_func, c->c_arg);
+
+ /* [re-]schedule callout, if any */
+ if (coa != NULL) {
+ cc = callout_cc_add_locked(c, cc, coa);
+ } else {
+ /* clear old flags, if any */
+ c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING |
+ CALLOUT_DEFRESTART | CALLOUT_PROCESSED);
+
+ /* return callback to pre-allocated list, if any */
+ if ((c->c_flags & CALLOUT_LOCAL_ALLOC) &&
+ cancelled != CALLOUT_RET_NORMAL) {
+ callout_cc_del(c, cc);
+ }
+ }
+ }
+ CC_UNLOCK(cc);
+ return (cancelled);
+}
+
/*
* New interface; clients allocate their own callout structures.
*
@@ -947,33 +1135,32 @@
*/
int
callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision,
- void (*ftn)(void *), void *arg, int cpu, int flags)
+ callout_func_t *ftn, void *arg, int cpu, int flags)
{
- sbintime_t to_sbt, pr;
- struct callout_cpu *cc;
- int cancelled, direct;
- int ignore_cpu=0;
+ struct callout_args coa;
- cancelled = 0;
- if (cpu == -1) {
- ignore_cpu = 1;
- } else if ((cpu >= MAXCPU) ||
- ((CC_CPU(cpu))->cc_inited == 0)) {
- /* Invalid CPU spec */
- panic("Invalid CPU in callout %d", cpu);
- }
- if (flags & C_ABSOLUTE) {
- to_sbt = sbt;
+ /* store arguments for callout add function */
+ coa.func = ftn;
+ coa.arg = arg;
+ coa.precision = precision;
+ coa.flags = flags;
+ coa.cpu = cpu;
+
+ /* compute the rest of the arguments needed */
+ if (coa.flags & C_ABSOLUTE) {
+ coa.time = sbt;
} else {
- if ((flags & C_HARDCLOCK) && (sbt < tick_sbt))
+ sbintime_t pr;
+
+ if ((coa.flags & C_HARDCLOCK) && (sbt < tick_sbt))
sbt = tick_sbt;
- if ((flags & C_HARDCLOCK) ||
+ if ((coa.flags & C_HARDCLOCK) ||
#ifdef NO_EVENTTIMERS
sbt >= sbt_timethreshold) {
- to_sbt = getsbinuptime();
+ coa.time = getsbinuptime();
/* Add safety belt for the case of hz > 1000. */
- to_sbt += tc_tick_sbt - tick_sbt;
+ coa.time += tc_tick_sbt - tick_sbt;
#else
sbt >= sbt_tickthreshold) {
/*
@@ -983,150 +1170,29 @@
* active ones.
*/
#ifdef __LP64__
- to_sbt = DPCPU_GET(hardclocktime);
+ coa.time = DPCPU_GET(hardclocktime);
#else
spinlock_enter();
- to_sbt = DPCPU_GET(hardclocktime);
+ coa.time = DPCPU_GET(hardclocktime);
spinlock_exit();
#endif
#endif
- if ((flags & C_HARDCLOCK) == 0)
- to_sbt += tick_sbt;
+ if ((coa.flags & C_HARDCLOCK) == 0)
+ coa.time += tick_sbt;
} else
- to_sbt = sbinuptime();
- if (SBT_MAX - to_sbt < sbt)
- to_sbt = SBT_MAX;
+ coa.time = sbinuptime();
+ if (SBT_MAX - coa.time < sbt)
+ coa.time = SBT_MAX;
else
- to_sbt += sbt;
- pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp :
- sbt >> C_PRELGET(flags));
- if (pr > precision)
- precision = pr;
- }
- /*
- * This flag used to be added by callout_cc_add, but the
- * first time you call this we could end up with the
- * wrong direct flag if we don't do it before we add.
- */
- if (flags & C_DIRECT_EXEC) {
- direct = 1;
- } else {
- direct = 0;
- }
- KASSERT(!direct || c->c_lock == NULL,
- ("%s: direct callout %p has lock", __func__, c));
- cc = callout_lock(c);
- /*
- * Don't allow migration of pre-allocated callouts lest they
- * become unbalanced or handle the case where the user does
- * not care.
- */
- if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) ||
- ignore_cpu) {
- cpu = c->c_cpu;
+ coa.time += sbt;
+ pr = ((C_PRELGET(coa.flags) < 0) ? sbt >> tc_precexp :
+ sbt >> C_PRELGET(coa.flags));
+ if (pr > coa.precision)
+ coa.precision = pr;
}
- if (cc_exec_curr(cc, direct) == c) {
- /*
- * We're being asked to reschedule a callout which is
- * currently in progress. If there is a lock then we
- * can cancel the callout if it has not really started.
- */
- if (c->c_lock != NULL && cc_exec_cancel(cc, direct))
- cancelled = cc_exec_cancel(cc, direct) = true;
- if (cc_exec_waiting(cc, direct)) {
- /*
- * Someone has called callout_drain to kill this
- * callout. Don't reschedule.
- */
- CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
- cancelled ? "cancelled" : "failed to cancel",
- c, c->c_func, c->c_arg);
- CC_UNLOCK(cc);
- return (cancelled);
- }
-#ifdef SMP
- if (callout_migrating(c)) {
- /*
- * This only occurs when a second callout_reset_sbt_on
- * is made after a previous one moved it into
- * deferred migration (below). Note we do *not* change
- * the prev_cpu even though the previous target may
- * be different.
- */
- cc_migration_cpu(cc, direct) = cpu;
- cc_migration_time(cc, direct) = to_sbt;
- cc_migration_prec(cc, direct) = precision;
- cc_migration_func(cc, direct) = ftn;
- cc_migration_arg(cc, direct) = arg;
- cancelled = 1;
- CC_UNLOCK(cc);
- return (cancelled);
- }
-#endif
- }
- if (c->c_iflags & CALLOUT_PENDING) {
- if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
- if (cc_exec_next(cc) == c)
- cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
- LIST_REMOVE(c, c_links.le);
- } else {
- TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
- }
- cancelled = 1;
- c->c_iflags &= ~ CALLOUT_PENDING;
- c->c_flags &= ~ CALLOUT_ACTIVE;
- }
-
-#ifdef SMP
- /*
- * If the callout must migrate try to perform it immediately.
- * If the callout is currently running, just defer the migration
- * to a more appropriate moment.
- */
- if (c->c_cpu != cpu) {
- if (cc_exec_curr(cc, direct) == c) {
- /*
- * Pending will have been removed since we are
- * actually executing the callout on another
- * CPU. That callout should be waiting on the
- * lock the caller holds. If we set both
- * active/and/pending after we return and the
- * lock on the executing callout proceeds, it
- * will then see pending is true and return.
- * At the return from the actual callout execution
- * the migration will occur in softclock_call_cc
- * and this new callout will be placed on the
- * new CPU via a call to callout_cpu_switch() which
- * will get the lock on the right CPU followed
- * by a call callout_cc_add() which will add it there.
- * (see above in softclock_call_cc()).
- */
- cc_migration_cpu(cc, direct) = cpu;
- cc_migration_time(cc, direct) = to_sbt;
- cc_migration_prec(cc, direct) = precision;
- cc_migration_func(cc, direct) = ftn;
- cc_migration_arg(cc, direct) = arg;
- c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING);
- c->c_flags |= CALLOUT_ACTIVE;
- CTR6(KTR_CALLOUT,
- "migration of %p func %p arg %p in %d.%08x to %u deferred",
- c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
- (u_int)(to_sbt & 0xffffffff), cpu);
- CC_UNLOCK(cc);
- return (cancelled);
- }
- cc = callout_cpu_switch(c, cc, cpu);
- }
-#endif
-
- callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags);
- CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x",
- cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
- (u_int)(to_sbt & 0xffffffff));
- CC_UNLOCK(cc);
-
- return (cancelled);
+ /* get callback started, if any */
+ return (callout_restart_async(c, &coa, NULL, NULL));
}
/*
@@ -1145,270 +1211,106 @@
}
int
-_callout_stop_safe(struct callout *c, int safe)
+callout_stop(struct callout *c)
{
- struct callout_cpu *cc, *old_cc;
- struct lock_class *class;
- int direct, sq_locked, use_lock;
- int not_on_a_list;
-
- if (safe)
- WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock,
- "calling %s", __func__);
+ /* get callback stopped, if any */
+ return (callout_restart_async(c, NULL, NULL, NULL));
+}
- /*
- * Some old subsystems don't hold Giant while running a callout_stop(),
- * so just discard this check for the moment.
- */
- if (!safe && c->c_lock != NULL) {
- if (c->c_lock == &Giant.lock_object)
- use_lock = mtx_owned(&Giant);
- else {
- use_lock = 1;
- class = LOCK_CLASS(c->c_lock);
- class->lc_assert(c->c_lock, LA_XLOCKED);
- }
- } else
- use_lock = 0;
- if (c->c_iflags & CALLOUT_DIRECT) {
- direct = 1;
- } else {
- direct = 0;
- }
- sq_locked = 0;
- old_cc = NULL;
-again:
- cc = callout_lock(c);
+static void
+callout_drain_function(void *arg)
+{
+ wakeup(arg);
+}
- if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) ==
- (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) &&
- ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) {
- /*
- * Special case where this slipped in while we
- * were migrating *as* the callout is about to
- * execute. The caller probably holds the lock
- * the callout wants.
- *
- * Get rid of the migration first. Then set
- * the flag that tells this code *not* to
- * try to remove it from any lists (its not
- * on one yet). When the callout wheel runs,
- * it will ignore this callout.
- */
- c->c_iflags &= ~CALLOUT_PENDING;
- c->c_flags &= ~CALLOUT_ACTIVE;
- not_on_a_list = 1;
- } else {
- not_on_a_list = 0;
- }
+int
+callout_drain_async(struct callout *c, callout_func_t *fn, void *arg)
+{
+ /* get callback stopped, if any */
+ return (callout_restart_async(
+ c, NULL, fn, arg) & CALLOUT_RET_DRAINING);
+}
- /*
- * If the callout was migrating while the callout cpu lock was
- * dropped, just drop the sleepqueue lock and check the states
- * again.
- */
- if (sq_locked != 0 && cc != old_cc) {
-#ifdef SMP
- CC_UNLOCK(cc);
- sleepq_release(&cc_exec_waiting(old_cc, direct));
- sq_locked = 0;
- old_cc = NULL;
- goto again;
-#else
- panic("migration should not happen");
-#endif
- }
+int
+callout_drain(struct callout *c)
+{
+ int cancelled;
- /*
- * If the callout isn't pending, it's not on the queue, so
- * don't attempt to remove it from the queue. We can try to
- * stop it by other means however.
- */
- if (!(c->c_iflags & CALLOUT_PENDING)) {
- c->c_flags &= ~CALLOUT_ACTIVE;
+ WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
+ "Draining callout");
+
+ callout_lock_client(c->c_flags, c->c_lock);
+
+ /* at this point the "c->c_cpu" field is not changing */
+
+ cancelled = callout_drain_async(c, &callout_drain_function, c);
+
+ if (cancelled != CALLOUT_RET_NORMAL) {
+ struct callout_cpu *cc;
+ int direct;
+
+ CTR3(KTR_CALLOUT, "need to drain %p func %p arg %p",
+ c, c->c_func, c->c_arg);
+
+ cc = callout_lock(c);
+ direct = ((c->c_flags & CALLOUT_DIRECT) != 0);
/*
- * If it wasn't on the queue and it isn't the current
- * callout, then we can't stop it, so just bail.
+ * We've gotten our callout CPU lock, it is safe to
+ * drop the initial lock:
*/
- if (cc_exec_curr(cc, direct) != c) {
- CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
- c, c->c_func, c->c_arg);
- CC_UNLOCK(cc);
- if (sq_locked)
- sleepq_release(&cc_exec_waiting(cc, direct));
- return (0);
- }
+ callout_unlock_client(c->c_flags, c->c_lock);
- if (safe) {
- /*
- * The current callout is running (or just
- * about to run) and blocking is allowed, so
- * just wait for the current invocation to
- * finish.
- */
- while (cc_exec_curr(cc, direct) == c) {
- /*
- * Use direct calls to sleepqueue interface
- * instead of cv/msleep in order to avoid
- * a LOR between cc_lock and sleepqueue
- * chain spinlocks. This piece of code
- * emulates a msleep_spin() call actually.
- *
- * If we already have the sleepqueue chain
- * locked, then we can safely block. If we
- * don't already have it locked, however,
- * we have to drop the cc_lock to lock
- * it. This opens several races, so we
- * restart at the beginning once we have
- * both locks. If nothing has changed, then
- * we will end up back here with sq_locked
- * set.
- */
- if (!sq_locked) {
- CC_UNLOCK(cc);
- sleepq_lock(
- &cc_exec_waiting(cc, direct));
- sq_locked = 1;
- old_cc = cc;
- goto again;
- }
+ /* Wait for drain to complete */
+
+ while (cc_exec_curr(cc, direct) == c)
+ msleep_spin(c, (struct mtx *)&cc->cc_lock, "codrain", 0);
- /*
- * Migration could be cancelled here, but
- * as long as it is still not sure when it
- * will be packed up, just let softclock()
- * take care of it.
- */
- cc_exec_waiting(cc, direct) = true;
- DROP_GIANT();
- CC_UNLOCK(cc);
- sleepq_add(
- &cc_exec_waiting(cc, direct),
- &cc->cc_lock.lock_object, "codrain",
- SLEEPQ_SLEEP, 0);
- sleepq_wait(
- &cc_exec_waiting(cc, direct),
- 0);
- sq_locked = 0;
- old_cc = NULL;
-
- /* Reacquire locks previously released. */
- PICKUP_GIANT();
- CC_LOCK(cc);
- }
- } else if (use_lock &&
- !cc_exec_cancel(cc, direct)) {
-
- /*
- * The current callout is waiting for its
- * lock which we hold. Cancel the callout
- * and return. After our caller drops the
- * lock, the callout will be skipped in
- * softclock().
- */
- cc_exec_cancel(cc, direct) = true;
- CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
- c, c->c_func, c->c_arg);
- KASSERT(!cc_cce_migrating(cc, direct),
- ("callout wrongly scheduled for migration"));
- if (callout_migrating(c)) {
- c->c_iflags &= ~CALLOUT_DFRMIGRATION;
-#ifdef SMP
- cc_migration_cpu(cc, direct) = CPUBLOCK;
- cc_migration_time(cc, direct) = 0;
- cc_migration_prec(cc, direct) = 0;
- cc_migration_func(cc, direct) = NULL;
- cc_migration_arg(cc, direct) = NULL;
-#endif
- }
- CC_UNLOCK(cc);
- KASSERT(!sq_locked, ("sleepqueue chain locked"));
- return (1);
- } else if (callout_migrating(c)) {
- /*
- * The callout is currently being serviced
- * and the "next" callout is scheduled at
- * its completion with a migration. We remove
- * the migration flag so it *won't* get rescheduled,
- * but we can't stop the one thats running so
- * we return 0.
- */
- c->c_iflags &= ~CALLOUT_DFRMIGRATION;
-#ifdef SMP
- /*
- * We can't call cc_cce_cleanup here since
- * if we do it will remove .ce_curr and
- * its still running. This will prevent a
- * reschedule of the callout when the
- * execution completes.
- */
- cc_migration_cpu(cc, direct) = CPUBLOCK;
- cc_migration_time(cc, direct) = 0;
- cc_migration_prec(cc, direct) = 0;
- cc_migration_func(cc, direct) = NULL;
- cc_migration_arg(cc, direct) = NULL;
-#endif
- CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p",
- c, c->c_func, c->c_arg);
- CC_UNLOCK(cc);
- return (0);
- }
- CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
- c, c->c_func, c->c_arg);
CC_UNLOCK(cc);
- KASSERT(!sq_locked, ("sleepqueue chain still locked"));
- return (0);
+ } else {
+ callout_unlock_client(c->c_flags, c->c_lock);
}
- if (sq_locked)
- sleepq_release(&cc_exec_waiting(cc, direct));
-
- c->c_iflags &= ~CALLOUT_PENDING;
- c->c_flags &= ~CALLOUT_ACTIVE;
CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
c, c->c_func, c->c_arg);
- if (not_on_a_list == 0) {
- if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
- if (cc_exec_next(cc) == c)
- cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
- LIST_REMOVE(c, c_links.le);
- } else {
- TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
- }
- }
- callout_cc_del(c, cc);
- CC_UNLOCK(cc);
- return (1);
+
+ return (cancelled & CALLOUT_RET_CANCELLED);
}
void
callout_init(struct callout *c, int mpsafe)
{
- bzero(c, sizeof *c);
if (mpsafe) {
- c->c_lock = NULL;
- c->c_iflags = CALLOUT_RETURNUNLOCKED;
+ _callout_init_lock(c, NULL, CALLOUT_RETURNUNLOCKED);
} else {
- c->c_lock = &Giant.lock_object;
- c->c_iflags = 0;
+ _callout_init_lock(c, &Giant.lock_object, 0);
}
- c->c_cpu = timeout_cpu;
}
void
_callout_init_lock(struct callout *c, struct lock_object *lock, int flags)
{
bzero(c, sizeof *c);
+ KASSERT((flags & ~CALLOUT_RETURNUNLOCKED) == 0,
+ ("callout_init_lock: bad flags 0x%08x", flags));
+ flags &= CALLOUT_RETURNUNLOCKED;
+ if (lock != NULL) {
+ struct lock_class *class = LOCK_CLASS(lock);
+ if (class == &lock_class_mtx_sleep)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_MUTEX);
+ else if (class == &lock_class_mtx_spin)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_SPIN);
+ else if (class == &lock_class_rm)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_RM);
+ else if (class == &lock_class_rw)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_RW);
+ else
+ panic("callout_init_lock: Unsupported lock class '%s'\n", class->lc_name);
+ } else {
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_UNUSED_0);
+ }
c->c_lock = lock;
- KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0,
- ("callout_init_lock: bad flags %d", flags));
- KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0,
- ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock"));
- KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags &
- (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class",
- __func__));
- c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK);
+ c->c_flags = flags;
c->c_cpu = timeout_cpu;
}
Index: projects/hps_head/sys/kern/subr_sleepqueue.c
===================================================================
--- projects/hps_head/sys/kern/subr_sleepqueue.c
+++ projects/hps_head/sys/kern/subr_sleepqueue.c
@@ -152,7 +152,8 @@
*/
static int sleepq_catch_signals(void *wchan, int pri);
static int sleepq_check_signals(void);
-static int sleepq_check_timeout(void);
+static int sleepq_check_timeout(struct thread *);
+static void sleepq_stop_timeout(struct thread *);
#ifdef INVARIANTS
static void sleepq_dtor(void *mem, int size, void *arg);
#endif
@@ -373,17 +374,14 @@
sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt, sbintime_t pr,
int flags)
{
- struct sleepqueue_chain *sc;
struct thread *td;
td = curthread;
- sc = SC_LOOKUP(wchan);
- mtx_assert(&sc->sc_lock, MA_OWNED);
- MPASS(TD_ON_SLEEPQ(td));
- MPASS(td->td_sleepqueue == NULL);
- MPASS(wchan != NULL);
+
+ mtx_lock_spin(&td->td_slpmutex);
callout_reset_sbt_on(&td->td_slpcallout, sbt, pr,
sleepq_timeout, td, PCPU_GET(cpuid), flags | C_DIRECT_EXEC);
+ mtx_unlock_spin(&td->td_slpmutex);
}
/*
@@ -559,11 +557,8 @@
* Check to see if we timed out.
*/
static int
-sleepq_check_timeout(void)
+sleepq_check_timeout(struct thread *td)
{
- struct thread *td;
-
- td = curthread;
THREAD_LOCK_ASSERT(td, MA_OWNED);
/*
@@ -573,28 +568,21 @@
td->td_flags &= ~TDF_TIMEOUT;
return (EWOULDBLOCK);
}
-
- /*
- * If TDF_TIMOFAIL is set, the timeout ran after we had
- * already been woken up.
- */
- if (td->td_flags & TDF_TIMOFAIL)
- td->td_flags &= ~TDF_TIMOFAIL;
-
- /*
- * If callout_stop() fails, then the timeout is running on
- * another CPU, so synchronize with it to avoid having it
- * accidentally wake up a subsequent sleep.
- */
- else if (callout_stop(&td->td_slpcallout) == 0) {
- td->td_flags |= TDF_TIMEOUT;
- TD_SET_SLEEPING(td);
- mi_switch(SW_INVOL | SWT_SLEEPQTIMO, NULL);
- }
return (0);
}
/*
+ * Atomically stop the timeout by using a mutex.
+ */
+static void
+sleepq_stop_timeout(struct thread *td)
+{
+ mtx_lock_spin(&td->td_slpmutex);
+ callout_stop(&td->td_slpcallout);
+ mtx_unlock_spin(&td->td_slpmutex);
+}
+
+/*
* Check to see if we were awoken by a signal.
*/
static int
@@ -664,9 +652,11 @@
MPASS(!(td->td_flags & TDF_SINTR));
thread_lock(td);
sleepq_switch(wchan, pri);
- rval = sleepq_check_timeout();
+ rval = sleepq_check_timeout(td);
thread_unlock(td);
+ sleepq_stop_timeout(td);
+
return (rval);
}
@@ -677,12 +667,18 @@
int
sleepq_timedwait_sig(void *wchan, int pri)
{
+ struct thread *td;
int rcatch, rvalt, rvals;
+ td = curthread;
+
rcatch = sleepq_catch_signals(wchan, pri);
- rvalt = sleepq_check_timeout();
+ rvalt = sleepq_check_timeout(td);
rvals = sleepq_check_signals();
- thread_unlock(curthread);
+ thread_unlock(td);
+
+ sleepq_stop_timeout(td);
+
if (rcatch)
return (rcatch);
if (rvals)
@@ -889,64 +885,49 @@
static void
sleepq_timeout(void *arg)
{
- struct sleepqueue_chain *sc;
- struct sleepqueue *sq;
- struct thread *td;
- void *wchan;
- int wakeup_swapper;
+ struct thread *td = arg;
+ int wakeup_swapper = 0;
- td = arg;
- wakeup_swapper = 0;
CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)",
(void *)td, (long)td->td_proc->p_pid, (void *)td->td_name);
- /*
- * First, see if the thread is asleep and get the wait channel if
- * it is.
- */
- thread_lock(td);
- if (TD_IS_SLEEPING(td) && TD_ON_SLEEPQ(td)) {
- wchan = td->td_wchan;
- sc = SC_LOOKUP(wchan);
- THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock);
- sq = sleepq_lookup(wchan);
- MPASS(sq != NULL);
- td->td_flags |= TDF_TIMEOUT;
- wakeup_swapper = sleepq_resume_thread(sq, td, 0);
- thread_unlock(td);
- if (wakeup_swapper)
- kick_proc0();
- return;
- }
+ /* Handle the three cases which can happen */
- /*
- * If the thread is on the SLEEPQ but isn't sleeping yet, it
- * can either be on another CPU in between sleepq_add() and
- * one of the sleepq_*wait*() routines or it can be in
- * sleepq_catch_signals().
- */
+ thread_lock(td);
if (TD_ON_SLEEPQ(td)) {
- td->td_flags |= TDF_TIMEOUT;
- thread_unlock(td);
- return;
- }
+ if (TD_IS_SLEEPING(td)) {
+ struct sleepqueue_chain *sc;
+ struct sleepqueue *sq;
+ void *wchan;
- /*
- * Now check for the edge cases. First, if TDF_TIMEOUT is set,
- * then the other thread has already yielded to us, so clear
- * the flag and resume it. If TDF_TIMEOUT is not set, then the
- * we know that the other thread is not on a sleep queue, but it
- * hasn't resumed execution yet. In that case, set TDF_TIMOFAIL
- * to let it know that the timeout has already run and doesn't
- * need to be canceled.
- */
- if (td->td_flags & TDF_TIMEOUT) {
- MPASS(TD_IS_SLEEPING(td));
- td->td_flags &= ~TDF_TIMEOUT;
- TD_CLR_SLEEPING(td);
- wakeup_swapper = setrunnable(td);
- } else
- td->td_flags |= TDF_TIMOFAIL;
+ /*
+ * Case I - thread is asleep and needs to be
+ * awoken:
+ */
+ wchan = td->td_wchan;
+ sc = SC_LOOKUP(wchan);
+ THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock);
+ sq = sleepq_lookup(wchan);
+ MPASS(sq != NULL);
+ td->td_flags |= TDF_TIMEOUT;
+ wakeup_swapper = sleepq_resume_thread(sq, td, 0);
+ } else {
+ /*
+ * Case II - cancel going to sleep by setting
+ * the timeout flag because the target thread
+ * is not asleep yet. It can be on another CPU
+ * in between sleepq_add() and one of the
+ * sleepq_*wait*() routines or it can be in
+ * sleepq_catch_signals().
+ */
+ td->td_flags |= TDF_TIMEOUT;
+ }
+ } else {
+ /*
+ * Case III - thread is already woken up by a wakeup
+ * call and should not timeout. Nothing to do!
+ */
+ }
thread_unlock(td);
if (wakeup_swapper)
kick_proc0();
Index: projects/hps_head/sys/ofed/include/linux/completion.h
===================================================================
--- projects/hps_head/sys/ofed/include/linux/completion.h
+++ projects/hps_head/sys/ofed/include/linux/completion.h
@@ -64,3 +64,4 @@
extern int linux_completion_done(struct completion *);
#endif /* _LINUX_COMPLETION_H_ */
+
Index: projects/hps_head/sys/ofed/include/linux/linux_compat.c
===================================================================
--- projects/hps_head/sys/ofed/include/linux/linux_compat.c
+++ projects/hps_head/sys/ofed/include/linux/linux_compat.c
@@ -846,7 +846,9 @@
if (c->done)
break;
sleepq_add(c, NULL, "completion", flags, 0);
+ sleepq_release(c);
sleepq_set_timeout(c, linux_timer_jiffies_until(end));
+ sleepq_lock(c);
if (flags & SLEEPQ_INTERRUPTIBLE)
ret = sleepq_timedwait_sig(c, 0);
else
Index: projects/hps_head/sys/sys/_callout.h
===================================================================
--- projects/hps_head/sys/sys/_callout.h
+++ projects/hps_head/sys/sys/_callout.h
@@ -46,6 +46,8 @@
SLIST_HEAD(callout_slist, callout);
TAILQ_HEAD(callout_tailq, callout);
+typedef void callout_func_t(void *);
+
struct callout {
union {
LIST_ENTRY(callout) le;
@@ -55,10 +57,9 @@
sbintime_t c_time; /* ticks to the event */
sbintime_t c_precision; /* delta allowed wrt opt */
void *c_arg; /* function argument */
- void (*c_func)(void *); /* function to call */
+ callout_func_t *c_func; /* function to call */
struct lock_object *c_lock; /* lock to handle */
- short c_flags; /* User State */
- short c_iflags; /* Internal State */
+ int c_flags; /* state of this entry */
volatile int c_cpu; /* CPU we're scheduled on */
};
Index: projects/hps_head/sys/sys/callout.h
===================================================================
--- projects/hps_head/sys/sys/callout.h
+++ projects/hps_head/sys/sys/callout.h
@@ -45,10 +45,12 @@
#define CALLOUT_PENDING 0x0004 /* callout is waiting for timeout */
#define CALLOUT_MPSAFE 0x0008 /* callout handler is mp safe */
#define CALLOUT_RETURNUNLOCKED 0x0010 /* handler returns with mtx unlocked */
-#define CALLOUT_SHAREDLOCK 0x0020 /* callout lock held in shared mode */
-#define CALLOUT_DFRMIGRATION 0x0040 /* callout in deferred migration mode */
+#define CALLOUT_UNUSED_5 0x0020 /* --available-- */
+#define CALLOUT_DEFRESTART 0x0040 /* callout restart is deferred */
#define CALLOUT_PROCESSED 0x0080 /* callout in wheel or processing list? */
#define CALLOUT_DIRECT 0x0100 /* allow exec from hw int context */
+#define CALLOUT_SET_LC(x) (((x) & 7) << 16) /* set lock class */
+#define CALLOUT_GET_LC(x) (((x) >> 16) & 7) /* get lock class */
#define C_DIRECT_EXEC 0x0001 /* direct execution of callout */
#define C_PRELBITS 7
@@ -63,25 +65,10 @@
};
#ifdef _KERNEL
-/*
- * Note the flags field is actually *two* fields. The c_flags
- * field is the one that caller operations that may, or may not have
- * a lock touches i.e. callout_deactivate(). The other, the c_iflags,
- * is the internal flags that *must* be kept correct on which the
- * callout system depend on e.g. callout_pending().
- * The c_iflag is used internally by the callout system to determine which
- * list the callout is on and track internal state. Callers *should not*
- * use the c_flags field directly but should use the macros provided.
- *
- * The c_iflags field holds internal flags that are protected by internal
- * locks of the callout subsystem. The c_flags field holds external flags.
- * The caller must hold its own lock while manipulating or reading external
- * flags via callout_active(), callout_deactivate(), callout_reset*(), or
- * callout_stop() to avoid races.
- */
#define callout_active(c) ((c)->c_flags & CALLOUT_ACTIVE)
#define callout_deactivate(c) ((c)->c_flags &= ~CALLOUT_ACTIVE)
-#define callout_drain(c) _callout_stop_safe(c, 1)
+int callout_drain(struct callout *);
+int callout_drain_async(struct callout *, callout_func_t *, void *);
void callout_init(struct callout *, int);
void _callout_init_lock(struct callout *, struct lock_object *, int);
#define callout_init_mtx(c, mtx, flags) \
@@ -93,9 +80,9 @@
#define callout_init_rw(c, rw, flags) \
_callout_init_lock((c), ((rw) != NULL) ? &(rw)->lock_object : \
NULL, (flags))
-#define callout_pending(c) ((c)->c_iflags & CALLOUT_PENDING)
+#define callout_pending(c) ((c)->c_flags & CALLOUT_PENDING)
int callout_reset_sbt_on(struct callout *, sbintime_t, sbintime_t,
- void (*)(void *), void *, int, int);
+ callout_func_t *, void *, int, int);
#define callout_reset_sbt(c, sbt, pr, fn, arg, flags) \
callout_reset_sbt_on((c), (sbt), (pr), (fn), (arg), -1, (flags))
#define callout_reset_sbt_curcpu(c, sbt, pr, fn, arg, flags) \
@@ -119,8 +106,7 @@
int callout_schedule_on(struct callout *, int, int);
#define callout_schedule_curcpu(c, on_tick) \
callout_schedule_on((c), (on_tick), PCPU_GET(cpuid))
-#define callout_stop(c) _callout_stop_safe(c, 0)
-int _callout_stop_safe(struct callout *, int);
+int callout_stop(struct callout *);
void callout_process(sbintime_t now);
#endif
Index: projects/hps_head/sys/sys/proc.h
===================================================================
--- projects/hps_head/sys/sys/proc.h
+++ projects/hps_head/sys/sys/proc.h
@@ -308,6 +308,7 @@
} td_uretoff; /* (k) Syscall aux returns. */
#define td_retval td_uretoff.tdu_retval
struct callout td_slpcallout; /* (h) Callout for sleep. */
+ struct mtx td_slpmutex; /* (h) Mutex for sleep callout */
struct trapframe *td_frame; /* (k) */
struct vm_object *td_kstack_obj;/* (a) Kstack object. */
vm_offset_t td_kstack; /* (a) Kernel VA of kstack. */
@@ -364,7 +365,7 @@
#define TDF_ALLPROCSUSP 0x00000200 /* suspended by SINGLE_ALLPROC */
#define TDF_BOUNDARY 0x00000400 /* Thread suspended at user boundary */
#define TDF_ASTPENDING 0x00000800 /* Thread has some asynchronous events. */
-#define TDF_TIMOFAIL 0x00001000 /* Timeout from sleep after we were awake. */
+#define TDF_UNUSED12 0x00001000 /* --available-- */
#define TDF_SBDRY 0x00002000 /* Stop only on usermode boundary. */
#define TDF_UPIBLOCKED 0x00004000 /* Thread blocked on user PI mutex. */
#define TDF_NEEDSUSPCHK 0x00008000 /* Thread may need to suspend. */
@@ -706,7 +707,7 @@
#define SWT_OWEPREEMPT 2 /* Switching due to opepreempt. */
#define SWT_TURNSTILE 3 /* Turnstile contention. */
#define SWT_SLEEPQ 4 /* Sleepq wait. */
-#define SWT_SLEEPQTIMO 5 /* Sleepq timeout wait. */
+#define SWT_UNUSED5 5 /* --available-- */
#define SWT_RELINQUISH 6 /* yield call. */
#define SWT_NEEDRESCHED 7 /* NEEDRESCHED was set. */
#define SWT_IDLE 8 /* Switching from the idle thread. */
Index: share/man/man9/Makefile
===================================================================
--- share/man/man9/Makefile
+++ share/man/man9/Makefile
@@ -1558,6 +1558,7 @@
timeout.9 callout_active.9 \
timeout.9 callout_deactivate.9 \
timeout.9 callout_drain.9 \
+ timeout.9 callout_drain_async.9 \
timeout.9 callout_handle_init.9 \
timeout.9 callout_init.9 \
timeout.9 callout_init_mtx.9 \
Index: share/man/man9/timeout.9
===================================================================
--- share/man/man9/timeout.9
+++ share/man/man9/timeout.9
@@ -29,13 +29,14 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 8, 2014
+.Dd January 24, 2015
.Dt TIMEOUT 9
.Os
.Sh NAME
.Nm callout_active ,
.Nm callout_deactivate ,
.Nm callout_drain ,
+.Nm callout_drain_async ,
.Nm callout_handle_init ,
.Nm callout_init ,
.Nm callout_init_mtx ,
@@ -63,256 +64,248 @@
.In sys/systm.h
.Bd -literal
typedef void timeout_t (void *);
+typedef void callout_func_t (void *);
.Ed
-.Ft int
-.Fn callout_active "struct callout *c"
-.Ft void
-.Fn callout_deactivate "struct callout *c"
-.Ft int
-.Fn callout_drain "struct callout *c"
-.Ft void
-.Fn callout_handle_init "struct callout_handle *handle"
-.Bd -literal
-struct callout_handle handle = CALLOUT_HANDLE_INITIALIZER(&handle);
-.Ed
-.Ft void
-.Fn callout_init "struct callout *c" "int mpsafe"
-.Ft void
-.Fn callout_init_mtx "struct callout *c" "struct mtx *mtx" "int flags"
-.Ft void
-.Fn callout_init_rm "struct callout *c" "struct rmlock *rm" "int flags"
-.Ft void
-.Fn callout_init_rw "struct callout *c" "struct rwlock *rw" "int flags"
-.Ft int
-.Fn callout_pending "struct callout *c"
-.Ft int
-.Fn callout_reset "struct callout *c" "int ticks" "timeout_t *func" "void *arg"
-.Ft int
-.Fn callout_reset_curcpu "struct callout *c" "int ticks" "timeout_t *func" \
-"void *arg"
-.Ft int
-.Fn callout_reset_on "struct callout *c" "int ticks" "timeout_t *func" \
-"void *arg" "int cpu"
-.Ft int
-.Fn callout_reset_sbt "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int flags"
-.Ft int
-.Fn callout_reset_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int flags"
-.Ft int
-.Fn callout_reset_sbt_on "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "timeout_t *func" "void *arg" "int cpu" "int flags"
-.Ft int
-.Fn callout_schedule "struct callout *c" "int ticks"
-.Ft int
-.Fn callout_schedule_curcpu "struct callout *c" "int ticks"
-.Ft int
-.Fn callout_schedule_on "struct callout *c" "int ticks" "int cpu"
-.Ft int
-.Fn callout_schedule_sbt "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int flags"
-.Ft int
-.Fn callout_schedule_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int flags"
-.Ft int
-.Fn callout_schedule_sbt_on "struct callout *c" "sbintime_t sbt" \
-"sbintime_t pr" "int cpu" "int flags"
-.Ft int
-.Fn callout_stop "struct callout *c"
-.Ft struct callout_handle
-.Fn timeout "timeout_t *func" "void *arg" "int ticks"
-.Ft void
-.Fn untimeout "timeout_t *func" "void *arg" "struct callout_handle handle"
.Sh DESCRIPTION
The
.Nm callout
-API is used to schedule a call to an arbitrary function at a specific
-time in the future.
-Consumers of this API are required to allocate a callout structure
-.Pq struct callout
+API is used to schedule a one-time call to an arbitrary function at a
+specific time in the future.
+Consumers of this API are required to allocate a
+.Ft struct callout
for each pending function invocation.
-This structure stores state about the pending function invocation including
-the function to be called and the time at which the function should be invoked.
-Pending function calls can be cancelled or rescheduled to a different time.
-In addition,
-a callout structure may be reused to schedule a new function call after a
-scheduled call is completed.
-.Pp
-Callouts only provide a single-shot mode.
-If a consumer requires a periodic timer,
-it must explicitly reschedule each function call.
-This is normally done by rescheduling the subsequent call within the called
-function.
-.Pp
-Callout functions must not sleep.
-They may not acquire sleepable locks,
-wait on condition variables,
-perform blocking allocation requests,
-or invoke any other action that might sleep.
-.Pp
-Each callout structure must be initialized by
-.Fn callout_init ,
-.Fn callout_init_mtx ,
-.Fn callout_init_rm ,
-or
-.Fn callout_init_rw
-before it is passed to any of the other callout functions.
The
+.Ft struct callout
+stores the full state about any pending function call and
+must be drained by a call to
+.Fn callout_drain
+or
+.Fn callout_drain_async
+before freeing.
+.Sh INITIALIZATION
+.Ft void
+.Fn callout_handle_init "struct callout_handle *handle"
+This function is deprecated.
+Please use
.Fn callout_init
-function initializes a callout structure in
-.Fa c
-that is not associated with a specific lock.
+instead.
+This function is used to prepare a
+.Ft struct callout_handle
+before it can be used the first time.
+If this function is called on a pending timeout, the pending timeout
+cannot be cancelled and the
+.Fn untimeout
+function will return as if no timeout was pending.
+.Pp
+.Fn CALLOUT_HANDLE_INITIALIZER "&handle"
+This macro is deprecated.
+This macro is used to statically initialize a
+.Ft struct callout_handle .
+Please use
+.Fn callout_init
+instead.
+.Pp
+.Ft void
+.Fn callout_init "struct callout *c" "int mpsafe"
+This function prepares a
+.Ft struct callout
+before it can be used.
+This function should not be used when the callout is pending a timeout.
If the
.Fa mpsafe
-argument is zero,
-the callout structure is not considered to be
-.Dq multi-processor safe ;
-and the Giant lock will be acquired before calling the callout function
-and released when the callout function returns.
-.Pp
-The
-.Fn callout_init_mtx ,
-.Fn callout_init_rm ,
-and
-.Fn callout_init_rw
-functions initialize a callout structure in
-.Fa c
-that is associated with a specific lock.
-The lock is specified by the
-.Fa mtx ,
-.Fa rm ,
-or
-.Fa rw
-parameter.
-The associated lock must be held while stopping or rescheduling the
-callout.
-The callout subsystem acquires the associated lock before calling the
-callout function and releases it after the function returns.
-If the callout was cancelled while the callout subsystem waited for the
-associated lock,
-the callout function is not called,
-and the associated lock is released.
-This ensures that stopping or rescheduling the callout will abort any
-previously scheduled invocation.
-.Pp
-Only regular mutexes may be used with
-.Fn callout_init_mtx ;
-spin mutexes are not supported.
-A sleepable read-mostly lock
-.Po
-one initialized with the
-.Dv RM_SLEEPABLE
-flag
-.Pc
-may not be used with
-.Fn callout_init_rm .
-Similarly, other sleepable lock types such as
-.Xr sx 9
-and
-.Xr lockmgr 9
-cannot be used with callouts because sleeping is not permitted in
-the callout subsystem.
+argument is non-zero, the callback function will be running unlocked
+and the callback is so-called "mpsafe".
+.Bf Sy
+It is the application's entire responsibility to not call any
+.Fn callout_xxx
+functions, including the
+.Fn callout_drain
+function, simultaneously on the same callout when the
+.Fa mpsafe
+argument is non-zero.
+Otherwise, undefined behavior can happen.
+Avoid simultaneous calls by obtaining an exclusive lock before calling
+any
+.Fn callout_xxx
+functions other than the
+.Fn callout_drain
+function.
+.Ef
+If the
+.Fa mpsafe
+argument is zero, the Giant mutex will be locked before the callback
+function is called.
+If the
+.Fa mpsafe
+argument is zero, the Giant mutex is expected to be locked when calling
+any
+.Fn callout_xxx
+functions which start and stop a callout other than the
+.Fn callout_drain
+function.
.Pp
-These
+.Ft void
+.Fn callout_init_mtx "struct callout *c" "struct mtx *mtx" "int flags"
+This function prepares a
+.Ft struct callout
+before it can be used.
+This function should not be used when the callout is pending a timeout.
+The
+.Fa mtx
+argument is a pointer to a valid spinlock type of mutex or a valid
+regular non-sleepable mutex which the callback subsystem will lock
+before calling the callback function.
+The specified mutex is expected to be locked when calling any
+.Fn callout_xxx
+functions which start and stop a callout other than the
+.Fn callout_drain
+function.
+Valid
.Fa flags
-may be specified for
-.Fn callout_init_mtx ,
-.Fn callout_init_rm ,
-or
-.Fn callout_init_rw :
+are:
.Bl -tag -width ".Dv CALLOUT_RETURNUNLOCKED"
.It Dv CALLOUT_RETURNUNLOCKED
-The callout function will release the associated lock itself,
-so the callout subsystem should not attempt to unlock it
-after the callout function returns.
-.It Dv CALLOUT_SHAREDLOCK
-The lock is only acquired in read mode when running the callout handler.
-This flag is ignored by
-.Fn callout_init_mtx .
+The callout function is assumed to have released the specified mutex
+before returning.
+.It Dv 0
+The callout subsystem will release the specified mutex after the
+callout function has returned.
.El
.Pp
-The function
-.Fn callout_stop
-cancels a callout
-.Fa c
-if it is currently pending.
-If the callout is pending, then
-.Fn callout_stop
-returns a non-zero value.
-If the callout is not set,
-has already been serviced,
-or is currently being serviced,
-then zero will be returned.
-If the callout has an associated lock,
-then that lock must be held when this function is called.
-.Pp
-The function
-.Fn callout_drain
-is identical to
-.Fn callout_stop
-except that it will wait for the callout
-.Fa c
-to complete if it is already in progress.
-This function MUST NOT be called while holding any
-locks on which the callout might block, or deadlock will result.
-Note that if the callout subsystem has already begun processing this
-callout, then the callout function may be invoked before
-.Fn callout_drain
-returns.
-However, the callout subsystem does guarantee that the callout will be
-fully stopped before
-.Fn callout_drain
-returns.
+.Ft void
+.Fn callout_init_rm "struct callout *c" "struct rmlock *rm" "int flags"
+This function is similar to
+.Fn callout_init_mtx ,
+but it accepts a read-mostly type of lock.
+The read-mostly lock must not be initialized with the
+.Dv RM_SLEEPABLE
+flag.
.Pp
-The
+.Ft void
+.Fn callout_init_rw "struct callout *c" "struct rwlock *rw" "int flags"
+This function is similar to
+.Fn callout_init_mtx ,
+but it accepts a read/write type of lock.
+.Sh SCHEDULING CALLOUTS
+.Ft struct callout_handle
+.Fn timeout "timeout_t *func" "void *arg" "int ticks"
+This function is deprecated.
+Please use
.Fn callout_reset
-and
-.Fn callout_schedule
-function families schedule a future function invocation for callout
-.Fa c .
-If
-.Fa c
-already has a pending callout,
-it is cancelled before the new invocation is scheduled.
-These functions return a non-zero value if a pending callout was cancelled
-and zero if there was no pending callout.
-If the callout has an associated lock,
-then that lock must be held when any of these functions are called.
-.Pp
-The time at which the callout function will be invoked is determined by
-either the
-.Fa ticks
-argument or the
-.Fa sbt ,
-.Fa pr ,
-and
-.Fa flags
-arguments.
-When
-.Fa ticks
-is used,
-the callout is scheduled to execute after
+instead.
+This function schedules a call to
+.Fa func
+to take place after
.Fa ticks Ns No /hz
seconds.
Non-positive values of
.Fa ticks
are silently converted to the value
.Sq 1 .
-.Pp
The
-.Fa sbt ,
-.Fa pr ,
-and
-.Fa flags
-arguments provide more control over the scheduled time including
-support for higher resolution times,
-specifying the precision of the scheduled time,
-and setting an absolute deadline instead of a relative timeout.
-The callout is scheduled to execute in a time window which begins at
-the time specified in
+.Fa func
+argument is a valid pointer to a function that takes a single
+.Fa void *
+argument.
+Upon invocation, the
+.Fa func
+function will receive
+.Fa arg
+as its only argument.
+The Giant lock is locked when the
+.Fa arg
+function is invoked and should not be unlocked by this function.
+The returned value from
+.Fn timeout
+is a
+.Ft struct callout_handle
+structure which can be used in conjunction with the
+.Fn untimeout
+function to request that a scheduled timeout be cancelled.
+As handles are recycled by the system, it is possible, although unlikely,
+that a handle from one invocation of
+.Fn timeout
+may match the handle of another invocation of
+.Fn timeout
+if both calls used the same function pointer and argument, and the first
+timeout is expired or cancelled before the second call.
+Please ensure that the function and argument pointers are unique when using this function.
+.Pp
+.Ft int
+.Fn callout_reset "struct callout *c" "int ticks" "callout_func_t *func" "void *arg"
+This function is used to schedule or re-schedule a callout.
+This function at first stops the callout given by the
+.Fa c
+argument, if any.
+Then it will start the callout given by the
+.Fa c
+argument.
+The relative time until the timeout callback happens is given by the
+.Fa ticks
+argument.
+The number of ticks in a second is defined by
+.Dv hz
+and can vary from system to system.
+This function returns a non-zero value if the given callout was pending and
+the callback function was prevented from being called.
+Otherwise, a value of zero is returned.
+If a lock is associated with the callout given by the
+.Fa c
+argument and it is exclusivly locked when this function is called, this
+function will always ensure that previous callback function, if any,
+is never reached.
+In other words, the callout will be atomically restarted.
+Otherwise, there is no such guarantee.
+The callback function is given by
+.Fa func
+and its function argument is given by
+.Fa arg .
+.Pp
+.Ft int
+.Fn callout_reset_curcpu "struct callout *c" "int ticks" "callout_func_t *func" \
+"void *arg"
+This function works the same like the
+.Fn callout_reset
+function except the callback function given by the
+.Fa func
+argument will be executed on the same CPU which called this function.
+A change in the CPU selection can only happen if the callout has a
+lock associated with it and this lock is locked when this function is
+called or the callout is marked "mpsafe".
+See
+.Fn callout_init .
+The CPU selection cannot be changed while the callout subsystem is
+processing the callback for completion.
+.Pp
+.Ft int
+.Fn callout_reset_on "struct callout *c" "int ticks" "callout_func_t *func" \
+"void *arg" "int cpu"
+This function works the same like the
+.Fn callout_reset
+function except the callback function given by the
+.Fa func
+argument will be executed on the CPU given by the
+.Fa cpu
+argument.
+A change in the CPU selection can only happen if the callout has a
+lock associated with it and this lock is locked when this function is
+called or the callout is marked "mpsafe".
+See
+.Fn callout_init .
+The CPU selection cannot be changed while the callout subsystem is
+processing the callback for completion.
+.Pp
+.Ft int
+.Fn callout_reset_sbt "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "callout_func_t *func" "void *arg" "int flags"
+This function works the same like the
+.Fn callout_reset
+function except the relative or absolute time after which the timeout
+callback should happen is given by the
.Fa sbt
-and extends for the amount of time specified in
+argument and extends for the amount of time specified in
.Fa pr .
+This function is used when high precision timeouts are needed.
If
.Fa sbt
specifies a time in the past,
@@ -322,12 +315,13 @@
allows the callout subsystem to coalesce callouts scheduled close to each
other into fewer timer interrupts,
reducing processing overhead and power consumption.
-These
+The
.Fa flags
-may be specified to adjust the interpretation of
+argument may be non-zero to adjust the interpretation of the
.Fa sbt
and
-.Fa pr :
+.Fa pr
+arguments:
.Bl -tag -width ".Dv C_DIRECT_EXEC"
.It Dv C_ABSOLUTE
Handle the
@@ -347,7 +341,7 @@
and should be as small as possible because they run with absolute priority.
.It Fn C_PREL
Specifies relative event time precision as binary logarithm of time interval
-divided by acceptable time deviation: 1 -- 1/2, 2 -- 1/4, etc.
+divided by acceptable time deviation: 1 -- 1/2, 2 -- 1/4, and so on.
Note that the larger of
.Fa pr
or this value is used as the length of the time window.
@@ -360,65 +354,221 @@
calls if possible.
.El
.Pp
-The
-.Fn callout_reset
-functions accept a
+.Ft int
+.Fn callout_reset_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "callout_func_t *func" "void *arg" "int flags"
+This function works like
+.Fn callout_reset_sbt ,
+except the callback function given by the
.Fa func
-argument which identifies the function to be called when the time expires.
-It must be a pointer to a function that takes a single
-.Fa void *
-argument.
-Upon invocation,
+argument will be executed on the CPU which called this function.
+A change in the CPU selection can only happen if the callout has a
+lock associated with it and this lock is locked when this function is
+called or the callout is marked "mpsafe".
+See
+.Fn callout_init .
+The CPU selection cannot be changed while the callout subsystem is
+processing the callback for completion.
+.Pp
+.Ft int
+.Fn callout_reset_sbt_on "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "callout_func_t *func" "void *arg" "int cpu" "int flags"
+This function works like
+.Fn callout_reset_sbt ,
+except the callback function given by
.Fa func
-will receive
-.Fa arg
-as its only argument.
-The
-.Fn callout_schedule
-functions reuse the
+will be executed on the CPU given by
+.Fa cpu .
+A change in the CPU selection can only happen if the callout has a
+lock associated with it and this lock is locked when this function is
+called or the callout is marked "mpsafe".
+See
+.Fn callout_init .
+The CPU selection cannot be changed while the callout subsystem is
+processing the callback for completion.
+.Pp
+.Ft int
+.Fn callout_schedule "struct callout *c" "int ticks"
+This function works the same like the
+.Fn callout_reset
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_curcpu "struct callout *c" "int ticks"
+This function works the same like the
+.Fn callout_reset_curcpu
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_on "struct callout *c" "int ticks" "int cpu"
+This function works the same like the
+.Fn callout_reset_on
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_sbt "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "int flags"
+This function works the same like the
+.Fn callout_reset_sbt
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_sbt_curcpu "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "int flags"
+This function works the same like the
+.Fn callout_reset_sbt_curcpu
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Pp
+.Ft int
+.Fn callout_schedule_sbt_on "struct callout *c" "sbintime_t sbt" \
+"sbintime_t pr" "int cpu" "int flags"
+This function works the same like the
+.Fn callout_reset_sbt_on
+function except it re-uses the callback function and the callback argument
+already stored in the
+.Pq struct callout
+structure.
+.Sh CHECKING THE STATE OF CALLOUTS
+.Ft int
+.Fn callout_pending "struct callout *c"
+This function returns non-zero if the callout pointed to by the
+.Fa c
+argument is pending for callback.
+Else this function returns zero.
+This function returns zero when inside the callout function if the
+callout is not re-scheduled.
+.Pp
+.Ft int
+.Fn callout_active "struct callout *c"
+This function is deprecated and returns non-zero if the callout
+pointed to by the
+.Fa c
+argument was scheduled in the past.
+Else this function returns zero.
+This function also returns zero after the
+.Fn callout_deactivate
+or the
+.Fn callout_stop
+or the
+.Fn callout_drain
+or the
+.Fn callout_drain_async
+function is called on the same callout as given by the
+.Fa c
+argument.
+.Pp
+.Ft void
+.Fn callout_deactivate "struct callout *c"
+This function is deprecated and ensures that subsequent calls to the
+.Fn callout_activate
+function returns zero until the callout is scheduled again.
+.Sh STOPPING CALLOUTS
+.Ft void
+.Fn untimeout "timeout_t *func" "void *arg" "struct callout_handle handle"
+This function is deprecated and cancels the timeout associated with the
+.Fa handle
+argument using the function pointed to by the
.Fa func
-and
+argument and having the
.Fa arg
-arguments from the previous callout.
-Note that one of the
-.Fn callout_reset
-functions must always be called to initialize
+arguments to validate the handle.
+If the handle does not correspond to a timeout with
+the function
.Fa func
-and
+taking the argument
.Fa arg
-before one of the
-.Fn callout_schedule
-functions can be used.
+no action is taken. The
+.Fa handle
+must be initialized by a previous call to
+.Fn timeout ,
+.Fn callout_handle_init
+or assigned the value of
+.Fn CALLOUT_HANDLE_INITIALIZER "&handle"
+before being passed to
+.Fn untimeout .
+The behavior of calling
+.Fn untimeout
+with an uninitialized handle
+is undefined.
.Pp
-The callout subsystem provides a softclock thread for each CPU in the system.
-Callouts are assigned to a single CPU and are executed by the softclock thread
-for that CPU.
-Initially,
-callouts are assigned to CPU 0.
-The
-.Fn callout_reset_on ,
-.Fn callout_reset_sbt_on ,
-.Fn callout_schedule_on
-and
-.Fn callout_schedule_sbt_on
-functions assign the callout to CPU
-.Fa cpu .
-The
-.Fn callout_reset_curcpu ,
-.Fn callout_reset_sbt_curpu ,
-.Fn callout_schedule_curcpu
-and
-.Fn callout_schedule_sbt_curcpu
-functions assign the callout to the current CPU.
-The
-.Fn callout_reset ,
-.Fn callout_reset_sbt ,
-.Fn callout_schedule
-and
-.Fn callout_schedule_sbt
-functions schedule the callout to execute in the softclock thread of the CPU
-to which it is currently assigned.
+.Ft int
+.Fn callout_stop "struct callout *c"
+This function is used to stop a timeout function invocation associated with the callout pointed to by the
+.Fa c
+argument, in a non-blocking fashion.
+This function can be called multiple times in a row with no side effects, even if the callout is already stopped. This function however should not be called before the callout has been initialized.
+This function returns a non-zero value if the given callout was pending and
+the callback function was prevented from being called.
+Else a value of zero is returned.
+If a lock is associated with the callout given by the
+.Fa c
+argument and it is exclusivly locked when this function is called, the
+.Fn callout_stop
+function will always ensure that the callback function is never reached.
+In other words the callout will be atomically stopped.
+Else there is no such guarantee.
+.Sh DRAINING CALLOUTS
+.Ft int
+.Fn callout_drain "struct callout *c"
+This function works the same like the
+.Fn callout_stop
+function except it ensures that all callback functions have returned and there are no more references to the callout pointed to by the
+.Fa c
+argument inside the callout subsystem before it returns.
+Also this function ensures that the lock, if any, associated with the
+callout is no longer being used.
+When this function returns, it is safe to free the callout structure pointed to by the
+.Fa c
+argument.
.Pp
+.Ft int
+.Fn callout_drain_async "struct callout *c" "callout_func_t *fn" "void *arg"
+This function is non-blocking and works the same like the
+.Fn callout_stop
+function except if it returns non-zero it means the callback function pointed to by the
+.Fa fn
+argument will be called back with the
+.Fa arg
+argument when all references to the callout pointed to by the
+.Fa c
+argument are gone.
+If this function returns non-zero it should not be called again until the callback function has been called.
+If the
+.Fn callout_drain
+or
+.Fn callout_drain_async
+functions are called while an asynchronous drain is pending,
+previously pending asynchronous drains might get cancelled.
+If this function returns zero, it is safe to free the callout structure pointed to by the
+.Fa c
+argument right away.
+.Sh CALLOUT FUNCTION RESTRICTIONS
+Callout functions must not sleep.
+They may not acquire sleepable locks, wait on condition variables,
+perform blocking allocation requests, or invoke any other action that
+might sleep.
+.Sh CALLOUT SUBSYSTEM INTERNALS
+The callout subsystem has its own set of spinlocks to protect its internal state.
+The callout subsystem provides a softclock thread for each CPU in the
+system.
+Callouts are assigned to a single CPU and are executed by the
+softclock thread for that CPU.
+Initially, callouts are assigned to CPU 0.
Softclock threads are not pinned to their respective CPUs by default.
The softclock thread for CPU 0 can be pinned to CPU 0 by setting the
.Va kern.pin_default_swi
@@ -427,50 +577,7 @@
respective CPUs by setting the
.Va kern.pin_pcpu_swi
loader tunable to a non-zero value.
-.Pp
-The macros
-.Fn callout_pending ,
-.Fn callout_active
-and
-.Fn callout_deactivate
-provide access to the current state of the callout.
-The
-.Fn callout_pending
-macro checks whether a callout is
-.Em pending ;
-a callout is considered
-.Em pending
-when a timeout has been set but the time has not yet arrived.
-Note that once the timeout time arrives and the callout subsystem
-starts to process this callout,
-.Fn callout_pending
-will return
-.Dv FALSE
-even though the callout function may not have finished
-.Pq or even begun
-executing.
-The
-.Fn callout_active
-macro checks whether a callout is marked as
-.Em active ,
-and the
-.Fn callout_deactivate
-macro clears the callout's
-.Em active
-flag.
-The callout subsystem marks a callout as
-.Em active
-when a timeout is set and it clears the
-.Em active
-flag in
-.Fn callout_stop
-and
-.Fn callout_drain ,
-but it
-.Em does not
-clear it when a callout expires normally via the execution of the
-callout function.
-.Ss "Avoiding Race Conditions"
+.Sh "AVOIDING RACE CONDITIONS"
The callout subsystem invokes callout functions from its own thread
context.
Without some kind of synchronization,
@@ -531,9 +638,8 @@
.Pc
indicates whether or not the callout was removed.
If it is known that the callout was set and the callout function has
-not yet executed, then a return value of
-.Dv FALSE
-indicates that the callout function is about to be called.
+not yet executed, then a return value of zero indicates that the
+callout function is about to be called.
For example:
.Bd -literal -offset indent
if (sc->sc_flags & SCFLG_CALLOUT_RUNNING) {
@@ -589,16 +695,14 @@
.Em pending
flag and return without action if
.Fn callout_pending
-returns
-.Dv TRUE .
+returns non-zero.
This indicates that the callout was rescheduled using
.Fn callout_reset
just before the callout function was invoked.
If
.Fn callout_active
-returns
-.Dv FALSE
-then the callout function should also return without action.
+returns zero then the callout function should also return without
+action.
This indicates that the callout has been stopped.
Finally, the callout function should call
.Fn callout_deactivate
@@ -668,129 +772,13 @@
or releasing the storage for the callout structure.
.Sh LEGACY API
.Bf Sy
-The functions below are a legacy API that will be removed in a future release.
-New code should not use these routines.
-.Ef
-.Pp
-The function
-.Fn timeout
-schedules a call to the function given by the argument
-.Fa func
-to take place after
-.Fa ticks Ns No /hz
-seconds.
-Non-positive values of
-.Fa ticks
-are silently converted to the value
-.Sq 1 .
-.Fa func
-should be a pointer to a function that takes a
-.Fa void *
-argument.
-Upon invocation,
-.Fa func
-will receive
-.Fa arg
-as its only argument.
-The return value from
+The
.Fn timeout
-is a
-.Ft struct callout_handle
-which can be used in conjunction with the
-.Fn untimeout
-function to request that a scheduled timeout be canceled.
-.Pp
-The function
-.Fn callout_handle_init
-can be used to initialize a handle to a state which will cause
-any calls to
-.Fn untimeout
-with that handle to return with no side
-effects.
-.Pp
-Assigning a callout handle the value of
-.Fn CALLOUT_HANDLE_INITIALIZER
-performs the same function as
-.Fn callout_handle_init
-and is provided for use on statically declared or global callout handles.
-.Pp
-The function
-.Fn untimeout
-cancels the timeout associated with
-.Fa handle
-using the
-.Fa func
and
-.Fa arg
-arguments to validate the handle.
-If the handle does not correspond to a timeout with
-the function
-.Fa func
-taking the argument
-.Fa arg
-no action is taken.
-.Fa handle
-must be initialized by a previous call to
-.Fn timeout ,
-.Fn callout_handle_init ,
-or assigned the value of
-.Fn CALLOUT_HANDLE_INITIALIZER "&handle"
-before being passed to
-.Fn untimeout .
-The behavior of calling
.Fn untimeout
-with an uninitialized handle
-is undefined.
-.Pp
-As handles are recycled by the system, it is possible (although unlikely)
-that a handle from one invocation of
-.Fn timeout
-may match the handle of another invocation of
-.Fn timeout
-if both calls used the same function pointer and argument, and the first
-timeout is expired or canceled before the second call.
-The timeout facility offers O(1) running time for
-.Fn timeout
-and
-.Fn untimeout .
-Timeouts are executed from
-.Fn softclock
-with the
-.Va Giant
-lock held.
-Thus they are protected from re-entrancy.
-.Sh RETURN VALUES
-The
-.Fn callout_active
-macro returns the state of a callout's
-.Em active
-flag.
-.Pp
-The
-.Fn callout_pending
-macro returns the state of a callout's
-.Em pending
-flag.
-.Pp
-The
-.Fn callout_reset
-and
-.Fn callout_schedule
-function families return non-zero if the callout was pending before the new
-function invocation was scheduled.
-.Pp
-The
-.Fn callout_stop
-and
-.Fn callout_drain
-functions return non-zero if the callout was still pending when it was
-called or zero otherwise.
-The
-.Fn timeout
-function returns a
-.Ft struct callout_handle
-that can be passed to
-.Fn untimeout .
+functions are a legacy API that will be removed in a future release.
+New code should not use these routines.
+.Ef
.Sh HISTORY
The current timeout and untimeout routines are based on the work of
.An Adam M. Costello
@@ -815,4 +803,4 @@
.Bx
linked list
callout mechanism which offered O(n) insertion and removal running time
-but did not generate or require handles for untimeout operations.
+and did not generate or require handles for untimeout operations.
Index: sys/kern/init_main.c
===================================================================
--- sys/kern/init_main.c
+++ sys/kern/init_main.c
@@ -505,7 +505,8 @@
callout_init_mtx(&p->p_itcallout, &p->p_mtx, 0);
callout_init_mtx(&p->p_limco, &p->p_mtx, 0);
- callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
+ mtx_init(&td->td_slpmutex, "td_slpmutex", NULL, MTX_SPIN);
+ callout_init_mtx(&td->td_slpcallout, &td->td_slpmutex, 0);
/* Create credentials. */
p->p_ucred = crget();
Index: sys/kern/kern_clocksource.c
===================================================================
--- sys/kern/kern_clocksource.c
+++ sys/kern/kern_clocksource.c
@@ -160,6 +160,9 @@
int usermode;
int done, runs;
+ KASSERT(curthread->td_critnest != 0,
+ ("Must be in a critical section"));
+
CTR3(KTR_SPARE2, "handle at %d: now %d.%08x",
curcpu, (int)(now >> 32), (u_int)(now & 0xffffffff));
done = 0;
Index: sys/kern/kern_condvar.c
===================================================================
--- sys/kern/kern_condvar.c
+++ sys/kern/kern_condvar.c
@@ -313,15 +313,13 @@
DROP_GIANT();
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0);
+ sleepq_release(cvp);
sleepq_set_timeout_sbt(cvp, sbt, pr, flags);
if (lock != &Giant.lock_object) {
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_release(cvp);
WITNESS_SAVE(lock, lock_witness);
lock_state = class->lc_unlock(lock);
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_lock(cvp);
}
+ sleepq_lock(cvp);
rval = sleepq_timedwait(cvp, 0);
#ifdef KTRACE
@@ -383,15 +381,13 @@
sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR |
SLEEPQ_INTERRUPTIBLE, 0);
+ sleepq_release(cvp);
sleepq_set_timeout_sbt(cvp, sbt, pr, flags);
if (lock != &Giant.lock_object) {
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_release(cvp);
WITNESS_SAVE(lock, lock_witness);
lock_state = class->lc_unlock(lock);
- if (class->lc_flags & LC_SLEEPABLE)
- sleepq_lock(cvp);
}
+ sleepq_lock(cvp);
rval = sleepq_timedwait_sig(cvp, 0);
#ifdef KTRACE
Index: sys/kern/kern_lock.c
===================================================================
--- sys/kern/kern_lock.c
+++ sys/kern/kern_lock.c
@@ -210,9 +210,11 @@
GIANT_SAVE();
sleepq_add(&lk->lock_object, NULL, wmesg, SLEEPQ_LK | (catch ?
SLEEPQ_INTERRUPTIBLE : 0), queue);
- if ((flags & LK_TIMELOCK) && timo)
+ if ((flags & LK_TIMELOCK) && timo) {
+ sleepq_release(&lk->lock_object);
sleepq_set_timeout(&lk->lock_object, timo);
-
+ sleepq_lock(&lk->lock_object);
+ }
/*
* Decisional switch for real sleeping.
*/
Index: sys/kern/kern_switch.c
===================================================================
--- sys/kern/kern_switch.c
+++ sys/kern/kern_switch.c
@@ -93,8 +93,6 @@
&DPCPU_NAME(sched_switch_stats[SWT_TURNSTILE]), "");
SCHED_STAT_DEFINE_VAR(sleepq,
&DPCPU_NAME(sched_switch_stats[SWT_SLEEPQ]), "");
-SCHED_STAT_DEFINE_VAR(sleepqtimo,
- &DPCPU_NAME(sched_switch_stats[SWT_SLEEPQTIMO]), "");
SCHED_STAT_DEFINE_VAR(relinquish,
&DPCPU_NAME(sched_switch_stats[SWT_RELINQUISH]), "");
SCHED_STAT_DEFINE_VAR(needresched,
Index: sys/kern/kern_synch.c
===================================================================
--- sys/kern/kern_synch.c
+++ sys/kern/kern_synch.c
@@ -236,12 +236,16 @@
* return from cursig().
*/
sleepq_add(ident, lock, wmesg, sleepq_flags, 0);
- if (sbt != 0)
- sleepq_set_timeout_sbt(ident, sbt, pr, flags);
if (lock != NULL && class->lc_flags & LC_SLEEPABLE) {
sleepq_release(ident);
WITNESS_SAVE(lock, lock_witness);
lock_state = class->lc_unlock(lock);
+ if (sbt != 0)
+ sleepq_set_timeout_sbt(ident, sbt, pr, flags);
+ sleepq_lock(ident);
+ } else if (sbt != 0) {
+ sleepq_release(ident);
+ sleepq_set_timeout_sbt(ident, sbt, pr, flags);
sleepq_lock(ident);
}
if (sbt != 0 && catch)
@@ -306,8 +310,11 @@
* We put ourselves on the sleep queue and start our timeout.
*/
sleepq_add(ident, &mtx->lock_object, wmesg, SLEEPQ_SLEEP, 0);
- if (sbt != 0)
+ if (sbt != 0) {
+ sleepq_release(ident);
sleepq_set_timeout_sbt(ident, sbt, pr, flags);
+ sleepq_lock(ident);
+ }
/*
* Can't call ktrace with any spin locks held so it can lock the
Index: sys/kern/kern_thread.c
===================================================================
--- sys/kern/kern_thread.c
+++ sys/kern/kern_thread.c
@@ -149,6 +149,9 @@
audit_thread_alloc(td);
#endif
umtx_thread_alloc(td);
+
+ mtx_init(&td->td_slpmutex, "td_slpmutex", NULL, MTX_SPIN);
+ callout_init_mtx(&td->td_slpcallout, &td->td_slpmutex, 0);
return (0);
}
@@ -162,6 +165,10 @@
td = (struct thread *)mem;
+ /* make sure to drain any use of the "td->td_slpcallout" */
+ callout_drain(&td->td_slpcallout);
+ mtx_destroy(&td->td_slpmutex);
+
#ifdef INVARIANTS
/* Verify that this thread is in a safe state to free. */
switch (td->td_state) {
@@ -544,7 +551,6 @@
LIST_INIT(&td->td_lprof[0]);
LIST_INIT(&td->td_lprof[1]);
sigqueue_init(&td->td_sigqueue, p);
- callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
TAILQ_INSERT_TAIL(&p->p_threads, td, td_plist);
p->p_numthreads++;
}
Index: sys/kern/kern_timeout.c
===================================================================
--- sys/kern/kern_timeout.c
+++ sys/kern/kern_timeout.c
@@ -54,6 +54,8 @@
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
+#include <sys/rmlock.h>
+#include <sys/rwlock.h>
#include <sys/proc.h>
#include <sys/sdt.h>
#include <sys/sleepqueue.h>
@@ -75,28 +77,25 @@
"struct callout *");
#ifdef CALLOUT_PROFILING
-static int avg_depth;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
+static int avg_depth[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth[0], 0,
"Average number of items examined per softclock call. Units = 1/1000");
-static int avg_gcalls;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
+static int avg_gcalls[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls[0], 0,
"Average number of Giant callouts made per softclock call. Units = 1/1000");
-static int avg_lockcalls;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0,
+static int avg_lockcalls[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls[0], 0,
"Average number of lock callouts made per softclock call. Units = 1/1000");
-static int avg_mpcalls;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
+static int avg_mpcalls[2];
+SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls[0], 0,
"Average number of MP callouts made per softclock call. Units = 1/1000");
-static int avg_depth_dir;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0,
+SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth[1], 0,
"Average number of direct callouts examined per callout_process call. "
"Units = 1/1000");
-static int avg_lockcalls_dir;
SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD,
- &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per "
+ &avg_lockcalls[1], 0, "Average number of lock direct callouts made per "
"callout_process call. Units = 1/1000");
-static int avg_mpcalls_dir;
-SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir,
+SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls[1],
0, "Average number of MP direct callouts made per callout_process call. "
"Units = 1/1000");
#endif
@@ -124,59 +123,274 @@
*/
u_int callwheelsize, callwheelmask;
+#define CALLOUT_RET_NORMAL 0
+#define CALLOUT_RET_CANCELLED 1
+#define CALLOUT_RET_DRAINING 2
+
+struct callout_args {
+ sbintime_t time; /* absolute time for the event */
+ sbintime_t precision; /* delta allowed wrt opt */
+ void *arg; /* function argument */
+ callout_func_t *func; /* function to call */
+ int flags; /* flags passed to callout_reset() */
+ int cpu; /* CPU we're scheduled on */
+};
+
+typedef void callout_mutex_op_t(struct lock_object *);
+typedef int callout_owned_op_t(struct lock_object *);
+
+struct callout_mutex_ops {
+ callout_mutex_op_t *lock;
+ callout_mutex_op_t *unlock;
+ callout_owned_op_t *owned;
+};
+
+enum {
+ CALLOUT_LC_UNUSED_0,
+ CALLOUT_LC_UNUSED_1,
+ CALLOUT_LC_UNUSED_2,
+ CALLOUT_LC_UNUSED_3,
+ CALLOUT_LC_SPIN,
+ CALLOUT_LC_MUTEX,
+ CALLOUT_LC_RW,
+ CALLOUT_LC_RM,
+};
+
+static void
+callout_mutex_op_none(struct lock_object *lock)
+{
+}
+
+static int
+callout_owned_op_none(struct lock_object *lock)
+{
+ return (0);
+}
+
+static void
+callout_mutex_lock(struct lock_object *lock)
+{
+
+ mtx_lock((struct mtx *)lock);
+}
+
+static void
+callout_mutex_unlock(struct lock_object *lock)
+{
+
+ mtx_unlock((struct mtx *)lock);
+}
+
+static void
+callout_mutex_lock_spin(struct lock_object *lock)
+{
+
+ mtx_lock_spin((struct mtx *)lock);
+}
+
+static void
+callout_mutex_unlock_spin(struct lock_object *lock)
+{
+
+ mtx_unlock_spin((struct mtx *)lock);
+}
+
+static int
+callout_mutex_owned(struct lock_object *lock)
+{
+
+ return (mtx_owned((struct mtx *)lock));
+}
+
+static void
+callout_rm_wlock(struct lock_object *lock)
+{
+
+ rm_wlock((struct rmlock *)lock);
+}
+
+static void
+callout_rm_wunlock(struct lock_object *lock)
+{
+
+ rm_wunlock((struct rmlock *)lock);
+}
+
+static int
+callout_rm_owned(struct lock_object *lock)
+{
+
+ return (rm_wowned((struct rmlock *)lock));
+}
+
+static void
+callout_rw_wlock(struct lock_object *lock)
+{
+
+ rw_wlock((struct rwlock *)lock);
+}
+
+static void
+callout_rw_wunlock(struct lock_object *lock)
+{
+
+ rw_wunlock((struct rwlock *)lock);
+}
+
+static int
+callout_rw_owned(struct lock_object *lock)
+{
+
+ return (rw_wowned((struct rwlock *)lock));
+}
+
+static const struct callout_mutex_ops callout_mutex_ops[8] = {
+ [CALLOUT_LC_UNUSED_0] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ .owned = callout_owned_op_none,
+ },
+ [CALLOUT_LC_UNUSED_1] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ .owned = callout_owned_op_none,
+ },
+ [CALLOUT_LC_UNUSED_2] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ .owned = callout_owned_op_none,
+ },
+ [CALLOUT_LC_UNUSED_3] = {
+ .lock = callout_mutex_op_none,
+ .unlock = callout_mutex_op_none,
+ .owned = callout_owned_op_none,
+ },
+ [CALLOUT_LC_SPIN] = {
+ .lock = callout_mutex_lock_spin,
+ .unlock = callout_mutex_unlock_spin,
+ .owned = callout_mutex_owned,
+ },
+ [CALLOUT_LC_MUTEX] = {
+ .lock = callout_mutex_lock,
+ .unlock = callout_mutex_unlock,
+ .owned = callout_mutex_owned,
+ },
+ [CALLOUT_LC_RW] = {
+ .lock = callout_rw_wlock,
+ .unlock = callout_rw_wunlock,
+ .owned = callout_rw_owned,
+ },
+ [CALLOUT_LC_RM] = {
+ .lock = callout_rm_wlock,
+ .unlock = callout_rm_wunlock,
+ .owned = callout_rm_owned,
+ },
+};
+
+static inline void
+callout_lock_client(int c_flags, struct lock_object *c_lock)
+{
+
+ callout_mutex_ops[CALLOUT_GET_LC(c_flags)].lock(c_lock);
+}
+
+static inline void
+callout_unlock_client(int c_flags, struct lock_object *c_lock)
+{
+
+ callout_mutex_ops[CALLOUT_GET_LC(c_flags)].unlock(c_lock);
+}
+
+#ifdef SMP
+static inline int
+callout_lock_owned_client(int c_flags, struct lock_object *c_lock)
+{
+
+ return (callout_mutex_ops[CALLOUT_GET_LC(c_flags)].owned(c_lock));
+}
+#endif
+
/*
- * The callout cpu exec entities represent informations necessary for
- * describing the state of callouts currently running on the CPU and the ones
- * necessary for migrating callouts to the new callout cpu. In particular,
- * the first entry of the array cc_exec_entity holds informations for callout
- * running in SWI thread context, while the second one holds informations
- * for callout running directly from hardware interrupt context.
- * The cached informations are very important for deferring migration when
- * the migrating callout is already running.
+ * The callout CPU exec structure represent information necessary for
+ * describing the state of callouts currently running on the CPU and
+ * for handling deferred callout restarts.
+ *
+ * In particular, the first entry of the array cc_exec_entity holds
+ * information for callouts running from the SWI thread context, while
+ * the second one holds information for callouts running directly from
+ * the hardware interrupt context.
*/
struct cc_exec {
+ /*
+ * The "cc_curr" points to the currently executing callout and
+ * is protected by the "cc_lock" spinlock. If no callback is
+ * currently executing it is equal to "NULL".
+ */
struct callout *cc_curr;
-#ifdef SMP
- void (*ce_migration_func)(void *);
- void *ce_migration_arg;
- int ce_migration_cpu;
- sbintime_t ce_migration_time;
- sbintime_t ce_migration_prec;
+ /*
+ * The "cc_restart_args" structure holds the argument for a
+ * deferred callback restart and is protected by the "cc_lock"
+ * spinlock. The structure is only valid if "cc_restart" is
+ * "true". If "cc_restart" is "false" the information in the
+ * "cc_restart_args" structure shall be ignored.
+ */
+ struct callout_args cc_restart_args;
+ bool cc_restart;
+ /*
+ * The "cc_cancel" variable allows the currently pending
+ * callback to be atomically cancelled. This field is write
+ * protected by the "cc_lock" spinlock.
+ */
+ bool cc_cancel;
+ /*
+ * The "cc_drain_fn" points to a function which shall be
+ * called with the argument stored in "cc_drain_arg" when an
+ * asynchronous drain is performed. This field is write
+ * protected by the "cc_lock" spinlock.
+ */
+ callout_func_t *cc_drain_fn;
+ void *cc_drain_arg;
+ /*
+ * The following fields are used for callout profiling only:
+ */
+#ifdef CALLOUT_PROFILING
+ int cc_depth;
+ int cc_mpcalls;
+ int cc_lockcalls;
+ int cc_gcalls;
#endif
- bool cc_cancel;
- bool cc_waiting;
};
/*
- * There is one struct callout_cpu per cpu, holding all relevant
+ * There is one "struct callout_cpu" per CPU, holding all relevant
* state for the callout processing thread on the individual CPU.
*/
struct callout_cpu {
struct mtx_padalign cc_lock;
struct cc_exec cc_exec_entity[2];
- struct callout *cc_next;
struct callout *cc_callout;
struct callout_list *cc_callwheel;
+ struct callout_list cc_tmplist;
struct callout_tailq cc_expireq;
struct callout_slist cc_callfree;
sbintime_t cc_firstevent;
sbintime_t cc_lastscan;
void *cc_cookie;
- u_int cc_bucket;
char cc_ktr_event_name[20];
};
-#define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr
-#define cc_exec_next(cc) cc->cc_next
-#define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel
-#define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting
-#ifdef SMP
-#define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func
-#define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg
-#define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu
-#define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time
-#define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec
+#define cc_exec_curr(cc, dir) (cc)->cc_exec_entity[(dir)].cc_curr
+#define cc_exec_restart_args(cc, dir) (cc)->cc_exec_entity[(dir)].cc_restart_args
+#define cc_exec_restart(cc, dir) (cc)->cc_exec_entity[(dir)].cc_restart
+#define cc_exec_cancel(cc, dir) (cc)->cc_exec_entity[(dir)].cc_cancel
+#define cc_exec_drain_fn(cc, dir) (cc)->cc_exec_entity[(dir)].cc_drain_fn
+#define cc_exec_drain_arg(cc, dir) (cc)->cc_exec_entity[(dir)].cc_drain_arg
+#define cc_exec_depth(cc, dir) (cc)->cc_exec_entity[(dir)].cc_depth
+#define cc_exec_mpcalls(cc, dir) (cc)->cc_exec_entity[(dir)].cc_mpcalls
+#define cc_exec_lockcalls(cc, dir) (cc)->cc_exec_entity[(dir)].cc_lockcalls
+#define cc_exec_gcalls(cc, dir) (cc)->cc_exec_entity[(dir)].cc_gcalls
+#ifdef SMP
struct callout_cpu cc_cpu[MAXCPU];
#define CPUBLOCK MAXCPU
#define CC_CPU(cpu) (&cc_cpu[(cpu)])
@@ -193,67 +407,13 @@
static int timeout_cpu;
static void callout_cpu_init(struct callout_cpu *cc, int cpu);
-static void softclock_call_cc(struct callout *c, struct callout_cpu *cc,
-#ifdef CALLOUT_PROFILING
- int *mpcalls, int *lockcalls, int *gcalls,
-#endif
- int direct);
+static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, const int direct);
static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures");
-/**
- * Locked by cc_lock:
- * cc_curr - If a callout is in progress, it is cc_curr.
- * If cc_curr is non-NULL, threads waiting in
- * callout_drain() will be woken up as soon as the
- * relevant callout completes.
- * cc_cancel - Changing to 1 with both callout_lock and cc_lock held
- * guarantees that the current callout will not run.
- * The softclock() function sets this to 0 before it
- * drops callout_lock to acquire c_lock, and it calls
- * the handler only if curr_cancelled is still 0 after
- * cc_lock is successfully acquired.
- * cc_waiting - If a thread is waiting in callout_drain(), then
- * callout_wait is nonzero. Set only when
- * cc_curr is non-NULL.
- */
-
-/*
- * Resets the execution entity tied to a specific callout cpu.
- */
-static void
-cc_cce_cleanup(struct callout_cpu *cc, int direct)
-{
-
- cc_exec_curr(cc, direct) = NULL;
- cc_exec_cancel(cc, direct) = false;
- cc_exec_waiting(cc, direct) = false;
-#ifdef SMP
- cc_migration_cpu(cc, direct) = CPUBLOCK;
- cc_migration_time(cc, direct) = 0;
- cc_migration_prec(cc, direct) = 0;
- cc_migration_func(cc, direct) = NULL;
- cc_migration_arg(cc, direct) = NULL;
-#endif
-}
-
-/*
- * Checks if migration is requested by a specific callout cpu.
- */
-static int
-cc_cce_migrating(struct callout_cpu *cc, int direct)
-{
-
-#ifdef SMP
- return (cc_migration_cpu(cc, direct) != CPUBLOCK);
-#else
- return (0);
-#endif
-}
-
/*
- * Kernel low level callwheel initialization
- * called on cpu0 during kernel startup.
+ * Kernel low level callwheel initialization called from cpu0 during
+ * kernel startup:
*/
static void
callout_callwheel_init(void *dummy)
@@ -313,8 +473,6 @@
LIST_INIT(&cc->cc_callwheel[i]);
TAILQ_INIT(&cc->cc_expireq);
cc->cc_firstevent = SBT_MAX;
- for (i = 0; i < 2; i++)
- cc_cce_cleanup(cc, i);
snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name),
"callwheel cpu %d", cpu);
if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */
@@ -322,38 +480,38 @@
for (i = 0; i < ncallout; i++) {
c = &cc->cc_callout[i];
callout_init(c, 0);
- c->c_flags = CALLOUT_LOCAL_ALLOC;
+ c->c_flags |= CALLOUT_LOCAL_ALLOC;
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
}
}
-#ifdef SMP
-/*
- * Switches the cpu tied to a specific callout.
- * The function expects a locked incoming callout cpu and returns with
- * locked outcoming callout cpu.
- */
-static struct callout_cpu *
-callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu)
+#ifdef CALLOUT_PROFILING
+static inline void
+callout_clear_stats(struct callout_cpu *cc, const int direct)
{
- struct callout_cpu *new_cc;
-
- MPASS(c != NULL && cc != NULL);
- CC_LOCK_ASSERT(cc);
+ cc_exec_depth(cc, direct) = 0;
+ cc_exec_mpcalls(cc, direct) = 0;
+ cc_exec_lockcalls(cc, direct) = 0;
+ cc_exec_gcalls(cc, direct) = 0;
+}
+#endif
- /*
- * Avoid interrupts and preemption firing after the callout cpu
- * is blocked in order to avoid deadlocks as the new thread
- * may be willing to acquire the callout cpu lock.
- */
- c->c_cpu = CPUBLOCK;
- spinlock_enter();
- CC_UNLOCK(cc);
- new_cc = CC_CPU(new_cpu);
- CC_LOCK(new_cc);
- spinlock_exit();
- c->c_cpu = new_cpu;
- return (new_cc);
+#ifdef CALLOUT_PROFILING
+static inline void
+callout_update_stats(struct callout_cpu *cc, const int direct)
+{
+ avg_depth[direct] +=
+ (cc_exec_depth(cc, direct) * 1000 -
+ avg_depth[direct]) >> 8;
+ avg_mpcalls[direct] +=
+ (cc_exec_mpcalls(cc, direct) * 1000 -
+ avg_mpcalls[direct]) >> 8;
+ avg_lockcalls[direct] +=
+ (cc_exec_lockcalls(cc, direct) * 1000 -
+ avg_lockcalls[direct]) >> 8;
+ avg_gcalls[direct] +=
+ (cc_exec_gcalls(cc, direct) * 1000 -
+ avg_gcalls[direct]) >> 8;
}
#endif
@@ -424,19 +582,19 @@
void
callout_process(sbintime_t now)
{
- struct callout *tmp, *tmpn;
+ struct callout *tmp;
struct callout_cpu *cc;
struct callout_list *sc;
sbintime_t first, last, max, tmp_max;
uint32_t lookahead;
u_int firstb, lastb, nowb;
-#ifdef CALLOUT_PROFILING
- int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0;
-#endif
cc = CC_SELF();
- mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET);
+ CC_LOCK(cc);
+#ifdef CALLOUT_PROFILING
+ callout_clear_stats(cc, 1);
+#endif
/* Compute the buckets of the last scan and present times. */
firstb = callout_hash(cc->cc_lastscan);
cc->cc_lastscan = now;
@@ -468,50 +626,47 @@
/* Iterate callwheel from firstb to nowb and then up to lastb. */
do {
+ LIST_INIT(&cc->cc_tmplist);
+
sc = &cc->cc_callwheel[firstb & callwheelmask];
- tmp = LIST_FIRST(sc);
- while (tmp != NULL) {
+ while (1) {
+ tmp = LIST_FIRST(sc);
+ if (tmp == NULL)
+ break;
+
+ LIST_REMOVE(tmp, c_links.le);
+
/* Run the callout if present time within allowed. */
if (tmp->c_time <= now) {
/*
- * Consumer told us the callout may be run
- * directly from hardware interrupt context.
+ * Consumer told us the callout may be
+ * run directly from the hardware
+ * interrupt context:
*/
if (tmp->c_flags & CALLOUT_DIRECT) {
-#ifdef CALLOUT_PROFILING
- ++depth_dir;
-#endif
- cc_exec_next(cc) =
- LIST_NEXT(tmp, c_links.le);
- cc->cc_bucket = firstb & callwheelmask;
- LIST_REMOVE(tmp, c_links.le);
- softclock_call_cc(tmp, cc,
-#ifdef CALLOUT_PROFILING
- &mpcalls_dir, &lockcalls_dir, NULL,
-#endif
- 1);
- tmp = cc_exec_next(cc);
- cc_exec_next(cc) = NULL;
+ softclock_call_cc(tmp, cc, 1);
} else {
- tmpn = LIST_NEXT(tmp, c_links.le);
- LIST_REMOVE(tmp, c_links.le);
TAILQ_INSERT_TAIL(&cc->cc_expireq,
tmp, c_links.tqe);
tmp->c_flags |= CALLOUT_PROCESSED;
- tmp = tmpn;
}
continue;
}
+
+ /* insert callout into temporary list */
+ LIST_INSERT_HEAD(&cc->cc_tmplist, tmp, c_links.le);
+
/* Skip events from distant future. */
if (tmp->c_time >= max)
- goto next;
+ continue;
+
/*
* Event minimal time is bigger than present maximal
* time, so it cannot be aggregated.
*/
if (tmp->c_time > last) {
lastb = nowb;
- goto next;
+ continue;
}
/* Update first and last time, respecting this event. */
if (tmp->c_time < first)
@@ -519,11 +674,14 @@
tmp_max = tmp->c_time + tmp->c_precision;
if (tmp_max < last)
last = tmp_max;
-next:
- tmp = LIST_NEXT(tmp, c_links.le);
}
+
+ /* Put temporary list back into the main bucket */
+ LIST_SWAP(sc, &cc->cc_tmplist, callout, c_links.le);
+
/* Proceed with the next bucket. */
firstb++;
+
/*
* Stop if we looked after present time and found
* some event we can't execute at now.
@@ -535,66 +693,70 @@
cpu_new_callout(curcpu, last, first);
#endif
#ifdef CALLOUT_PROFILING
- avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8;
- avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8;
- avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8;
+ callout_update_stats(cc, 1);
#endif
- mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET);
+ CC_UNLOCK(cc);
/*
- * swi_sched acquires the thread lock, so we don't want to call it
- * with cc_lock held; incorrect locking order.
+ * "swi_sched()" acquires the thread lock and we don't want to
+ * call it having cc_lock held because it leads to a locking
+ * order reversal issue.
*/
if (!TAILQ_EMPTY(&cc->cc_expireq))
swi_sched(cc->cc_cookie, 0);
}
-static struct callout_cpu *
+static inline struct callout_cpu *
callout_lock(struct callout *c)
{
struct callout_cpu *cc;
- int cpu;
-
- for (;;) {
- cpu = c->c_cpu;
-#ifdef SMP
- if (cpu == CPUBLOCK) {
- while (c->c_cpu == CPUBLOCK)
- cpu_spinwait();
- continue;
- }
-#endif
- cc = CC_CPU(cpu);
- CC_LOCK(cc);
- if (cpu == c->c_cpu)
- break;
- CC_UNLOCK(cc);
- }
+ cc = CC_CPU(c->c_cpu);
+ CC_LOCK(cc);
return (cc);
}
-static void
-callout_cc_add(struct callout *c, struct callout_cpu *cc,
- sbintime_t sbt, sbintime_t precision, void (*func)(void *),
- void *arg, int cpu, int flags)
+static struct callout_cpu *
+callout_cc_add_locked(struct callout *c, struct callout_cpu *cc,
+ struct callout_args *coa, bool can_swap_cpu)
{
+#ifndef NO_EVENTTIMERS
+ sbintime_t sbt;
+#endif
int bucket;
CC_LOCK_ASSERT(cc);
- if (sbt < cc->cc_lastscan)
- sbt = cc->cc_lastscan;
- c->c_arg = arg;
- c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
- c->c_flags &= ~CALLOUT_PROCESSED;
- c->c_func = func;
- c->c_time = sbt;
- c->c_precision = precision;
+
+ /* update flags before swapping locks, if any */
+ c->c_flags &= ~(CALLOUT_PROCESSED | CALLOUT_DIRECT | CALLOUT_DEFRESTART);
+ if (coa->flags & C_DIRECT_EXEC)
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING | CALLOUT_DIRECT);
+ else
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING);
+
+#ifdef SMP
+ /*
+ * Check if we are changing the CPU on which the callback
+ * should be executed and if we have a lock protecting us:
+ */
+ if (can_swap_cpu != false && coa->cpu != c->c_cpu &&
+ callout_lock_owned_client(c->c_flags, c->c_lock) != 0) {
+ CC_UNLOCK(cc);
+ c->c_cpu = coa->cpu;
+ cc = callout_lock(c);
+ }
+#endif
+ if (coa->time < cc->cc_lastscan)
+ coa->time = cc->cc_lastscan;
+ c->c_arg = coa->arg;
+ c->c_func = coa->func;
+ c->c_time = coa->time;
+ c->c_precision = coa->precision;
+
bucket = callout_get_bucket(c->c_time);
CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x",
c, (int)(c->c_precision >> 32),
(u_int)(c->c_precision & 0xffffffff));
LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le);
- if (cc->cc_bucket == bucket)
- cc_exec_next(cc) = c;
+
#ifndef NO_EVENTTIMERS
/*
* Inform the eventtimers(4) subsystem there's a new callout
@@ -605,42 +767,28 @@
sbt = c->c_time + c->c_precision;
if (sbt < cc->cc_firstevent) {
cc->cc_firstevent = sbt;
- cpu_new_callout(cpu, sbt, c->c_time);
+ cpu_new_callout(c->c_cpu, sbt, c->c_time);
}
#endif
+ return (cc);
}
-static void
+static inline void
callout_cc_del(struct callout *c, struct callout_cpu *cc)
{
- if ((c->c_flags & CALLOUT_LOCAL_ALLOC) == 0)
- return;
c->c_func = NULL;
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
}
-static void
+static inline void
softclock_call_cc(struct callout *c, struct callout_cpu *cc,
-#ifdef CALLOUT_PROFILING
- int *mpcalls, int *lockcalls, int *gcalls,
-#endif
- int direct)
+ const int direct)
{
- struct rm_priotracker tracker;
- void (*c_func)(void *);
+ callout_func_t *c_func;
void *c_arg;
- struct lock_class *class;
struct lock_object *c_lock;
- uintptr_t lock_status;
int c_flags;
-#ifdef SMP
- struct callout_cpu *new_cc;
- void (*new_func)(void *);
- void *new_arg;
- int flags, new_cpu;
- sbintime_t new_prec, new_time;
-#endif
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
sbintime_t sbt1, sbt2;
struct timespec ts2;
@@ -651,58 +799,65 @@
KASSERT((c->c_flags & (CALLOUT_PENDING | CALLOUT_ACTIVE)) ==
(CALLOUT_PENDING | CALLOUT_ACTIVE),
("softclock_call_cc: pend|act %p %x", c, c->c_flags));
- class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL;
- lock_status = 0;
- if (c->c_flags & CALLOUT_SHAREDLOCK) {
- if (class == &lock_class_rm)
- lock_status = (uintptr_t)&tracker;
- else
- lock_status = 1;
- }
+
c_lock = c->c_lock;
c_func = c->c_func;
c_arg = c->c_arg;
c_flags = c->c_flags;
- if (c->c_flags & CALLOUT_LOCAL_ALLOC)
- c->c_flags = CALLOUT_LOCAL_ALLOC;
- else
- c->c_flags &= ~CALLOUT_PENDING;
-
+
+ /* remove pending bit */
+ c->c_flags &= ~CALLOUT_PENDING;
+
+ /* reset our local state */
cc_exec_curr(cc, direct) = c;
- cc_exec_cancel(cc, direct) = false;
- CC_UNLOCK(cc);
+ cc_exec_restart(cc, direct) = false;
+ cc_exec_drain_fn(cc, direct) = NULL;
+ cc_exec_drain_arg(cc, direct) = NULL;
+
if (c_lock != NULL) {
- class->lc_lock(c_lock, lock_status);
+ cc_exec_cancel(cc, direct) = false;
+ CC_UNLOCK(cc);
+
+ /* unlocked region for switching locks */
+
+ callout_lock_client(c_flags, c_lock);
+
/*
- * The callout may have been cancelled
- * while we switched locks.
+ * Check if the callout may have been cancelled while
+ * we were switching locks. Even though the callout is
+ * specifying a lock, it might not be certain this
+ * lock is locked when starting and stopping callouts.
*/
+ CC_LOCK(cc);
if (cc_exec_cancel(cc, direct)) {
- class->lc_unlock(c_lock);
- goto skip;
+ callout_unlock_client(c_flags, c_lock);
+ goto skip_cc_locked;
}
- /* The callout cannot be stopped now. */
- cc_exec_cancel(cc, direct) = true;
if (c_lock == &Giant.lock_object) {
#ifdef CALLOUT_PROFILING
- (*gcalls)++;
+ cc_exec_gcalls(cc, direct)++;
#endif
CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p",
c, c_func, c_arg);
} else {
#ifdef CALLOUT_PROFILING
- (*lockcalls)++;
+ cc_exec_lockcalls(cc, direct)++;
#endif
CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p",
c, c_func, c_arg);
}
} else {
#ifdef CALLOUT_PROFILING
- (*mpcalls)++;
+ cc_exec_mpcalls(cc, direct)++;
#endif
CTR3(KTR_CALLOUT, "callout %p func %p arg %p",
c, c_func, c_arg);
}
+ /* The callout cannot be stopped now! */
+ cc_exec_cancel(cc, direct) = true;
+ CC_UNLOCK(cc);
+
+ /* unlocked region */
KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running",
"func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct);
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
@@ -729,85 +884,40 @@
#endif
KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle");
CTR1(KTR_CALLOUT, "callout %p finished", c);
+
+ /*
+ * At this point the callback structure might have been freed,
+ * so we need to check the previously copied value of
+ * "c->c_flags":
+ */
if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0)
- class->lc_unlock(c_lock);
-skip:
+ callout_unlock_client(c_flags, c_lock);
+
CC_LOCK(cc);
+
+skip_cc_locked:
KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr"));
cc_exec_curr(cc, direct) = NULL;
- if (cc_exec_waiting(cc, direct)) {
- /*
- * There is someone waiting for the
- * callout to complete.
- * If the callout was scheduled for
- * migration just cancel it.
- */
- if (cc_cce_migrating(cc, direct)) {
- cc_cce_cleanup(cc, direct);
-
- /*
- * It should be assert here that the callout is not
- * destroyed but that is not easy.
- */
- c->c_flags &= ~CALLOUT_DFRMIGRATION;
- }
- cc_exec_waiting(cc, direct) = false;
- CC_UNLOCK(cc);
- wakeup(&cc_exec_waiting(cc, direct));
- CC_LOCK(cc);
- } else if (cc_cce_migrating(cc, direct)) {
- KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0,
- ("Migrating legacy callout %p", c));
-#ifdef SMP
- /*
- * If the callout was scheduled for
- * migration just perform it now.
- */
- new_cpu = cc_migration_cpu(cc, direct);
- new_time = cc_migration_time(cc, direct);
- new_prec = cc_migration_prec(cc, direct);
- new_func = cc_migration_func(cc, direct);
- new_arg = cc_migration_arg(cc, direct);
- cc_cce_cleanup(cc, direct);
+ /* Check if there is anything which needs draining */
+ if (cc_exec_drain_fn(cc, direct) != NULL) {
/*
- * It should be assert here that the callout is not destroyed
- * but that is not easy.
- *
- * As first thing, handle deferred callout stops.
+ * Unlock the CPU callout last, so that any use of
+ * structures belonging to the callout are complete:
*/
- if (!callout_migrating(c)) {
- CTR3(KTR_CALLOUT,
- "deferred cancelled %p func %p arg %p",
- c, new_func, new_arg);
- callout_cc_del(c, cc);
- return;
- }
- c->c_flags &= ~CALLOUT_DFRMIGRATION;
-
- new_cc = callout_cpu_switch(c, cc, new_cpu);
- flags = (direct) ? C_DIRECT_EXEC : 0;
- callout_cc_add(c, new_cc, new_time, new_prec, new_func,
- new_arg, new_cpu, flags);
- CC_UNLOCK(new_cc);
+ CC_UNLOCK(cc);
+ /* call drain function unlocked */
+ cc_exec_drain_fn(cc, direct)(
+ cc_exec_drain_arg(cc, direct));
CC_LOCK(cc);
-#else
- panic("migration should not happen");
-#endif
- }
- /*
- * If the current callout is locally allocated (from
- * timeout(9)) then put it on the freelist.
- *
- * Note: we need to check the cached copy of c_flags because
- * if it was not local, then it's not safe to deref the
- * callout pointer.
- */
- KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0 ||
- c->c_flags == CALLOUT_LOCAL_ALLOC,
- ("corrupted callout"));
- if (c_flags & CALLOUT_LOCAL_ALLOC)
+ } else if (c_flags & CALLOUT_LOCAL_ALLOC) {
+ /* return callout back to freelist */
callout_cc_del(c, cc);
+ } else if (cc_exec_restart(cc, direct)) {
+ /* [re-]schedule callout, if any */
+ (void) callout_cc_add_locked(c, cc,
+ &cc_exec_restart_args(cc, direct), false);
+ }
}
/*
@@ -831,28 +941,18 @@
{
struct callout_cpu *cc;
struct callout *c;
-#ifdef CALLOUT_PROFILING
- int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0;
-#endif
cc = (struct callout_cpu *)arg;
CC_LOCK(cc);
- while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) {
- TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
- softclock_call_cc(c, cc,
-#ifdef CALLOUT_PROFILING
- &mpcalls, &lockcalls, &gcalls,
-#endif
- 0);
#ifdef CALLOUT_PROFILING
- ++depth;
+ callout_clear_stats(cc, 0);
#endif
+ while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) {
+ TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
+ softclock_call_cc(c, cc, 0);
}
#ifdef CALLOUT_PROFILING
- avg_depth += (depth * 1000 - avg_depth) >> 8;
- avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
- avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
- avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
+ callout_update_stats(cc, 0);
#endif
CC_UNLOCK(cc);
}
@@ -888,10 +988,11 @@
/* XXX Attempt to malloc first */
panic("timeout table full");
SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle);
- callout_reset(new, to_ticks, ftn, arg);
handle.callout = new;
CC_UNLOCK(cc);
+ callout_reset(new, to_ticks, ftn, arg);
+
return (handle);
}
@@ -899,6 +1000,7 @@
untimeout(timeout_t *ftn, void *arg, struct callout_handle handle)
{
struct callout_cpu *cc;
+ bool match;
/*
* Check for a handle that was initialized
@@ -909,9 +1011,11 @@
return;
cc = callout_lock(handle.callout);
- if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
- callout_stop(handle.callout);
+ match = (handle.callout->c_func == ftn && handle.callout->c_arg == arg);
CC_UNLOCK(cc);
+
+ if (match)
+ callout_stop(handle.callout);
}
void
@@ -920,6 +1024,118 @@
handle->callout = NULL;
}
+static int
+callout_restart_async(struct callout *c, struct callout_args *coa,
+ callout_func_t *drain_fn, void *drain_arg)
+{
+ struct callout_cpu *cc;
+ int cancelled;
+ int direct;
+
+ cc = callout_lock(c);
+
+ /* Figure out if the callout is direct or not */
+ direct = ((c->c_flags & CALLOUT_DIRECT) != 0);
+
+ /*
+ * Check if the callback is currently scheduled for
+ * completion:
+ */
+ if (cc_exec_curr(cc, direct) == c) {
+ /*
+ * Try to prevent the callback from running by setting
+ * the "cc_cancel" variable to "true". Also check if
+ * the callout was previously subject to a deferred
+ * callout restart:
+ */
+ if (cc_exec_cancel(cc, direct) == false ||
+ (c->c_flags & CALLOUT_DEFRESTART) != 0) {
+ cc_exec_cancel(cc, direct) = true;
+ cancelled = CALLOUT_RET_CANCELLED;
+ } else {
+ cancelled = CALLOUT_RET_NORMAL;
+ }
+
+ /*
+ * Prevent callback restart if "callout_drain_xxx()"
+ * is being called or we are stopping the callout or
+ * the callback was preallocated by us:
+ */
+ if (cc_exec_drain_fn(cc, direct) != NULL ||
+ coa == NULL || (c->c_flags & CALLOUT_LOCAL_ALLOC) != 0) {
+ CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
+ cancelled ? "cancelled and draining" : "draining",
+ c, c->c_func, c->c_arg);
+
+ /* clear old flags, if any */
+ c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING |
+ CALLOUT_DEFRESTART | CALLOUT_PROCESSED);
+
+ /* clear restart flag, if any */
+ cc_exec_restart(cc, direct) = false;
+
+ /* set drain function, if any */
+ if (drain_fn != NULL) {
+ cc_exec_drain_fn(cc, direct) = drain_fn;
+ cc_exec_drain_arg(cc, direct) = drain_arg;
+ cancelled |= CALLOUT_RET_DRAINING;
+ }
+ } else {
+ CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
+ cancelled ? "cancelled and restarting" : "restarting",
+ c, c->c_func, c->c_arg);
+
+ /* get us back into the game */
+ c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING |
+ CALLOUT_DEFRESTART);
+ c->c_flags &= ~CALLOUT_PROCESSED;
+
+ /* enable deferred restart */
+ cc_exec_restart(cc, direct) = true;
+
+ /* store arguments for the deferred restart, if any */
+ cc_exec_restart_args(cc, direct) = *coa;
+ }
+ } else {
+ /* stop callout */
+ if (c->c_flags & CALLOUT_PENDING) {
+ /*
+ * The callback has not yet been executed, and
+ * we simply just need to unlink it:
+ */
+ if ((c->c_flags & CALLOUT_PROCESSED) == 0) {
+ LIST_REMOVE(c, c_links.le);
+ } else {
+ TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
+ }
+ cancelled = CALLOUT_RET_CANCELLED;
+ } else {
+ cancelled = CALLOUT_RET_NORMAL;
+ }
+
+ CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
+ cancelled ? "rescheduled" : "scheduled",
+ c, c->c_func, c->c_arg);
+
+ /* [re-]schedule callout, if any */
+ if (coa != NULL) {
+ cc = callout_cc_add_locked(c, cc, coa, true);
+ } else {
+ /* clear old flags, if any */
+ c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING |
+ CALLOUT_DEFRESTART | CALLOUT_PROCESSED);
+
+ /* return callback to pre-allocated list, if any */
+ if ((c->c_flags & CALLOUT_LOCAL_ALLOC) &&
+ cancelled != CALLOUT_RET_NORMAL) {
+ callout_cc_del(c, cc);
+ }
+ }
+ }
+ CC_UNLOCK(cc);
+ return (cancelled);
+}
+
/*
* New interface; clients allocate their own callout structures.
*
@@ -938,25 +1154,32 @@
*/
int
callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision,
- void (*ftn)(void *), void *arg, int cpu, int flags)
+ callout_func_t *ftn, void *arg, int cpu, int flags)
{
- sbintime_t to_sbt, pr;
- struct callout_cpu *cc;
- int cancelled, direct;
+ struct callout_args coa;
- cancelled = 0;
- if (flags & C_ABSOLUTE) {
- to_sbt = sbt;
+ /* store arguments for callout add function */
+ coa.func = ftn;
+ coa.arg = arg;
+ coa.precision = precision;
+ coa.flags = flags;
+ coa.cpu = cpu;
+
+ /* compute the rest of the arguments needed */
+ if (coa.flags & C_ABSOLUTE) {
+ coa.time = sbt;
} else {
- if ((flags & C_HARDCLOCK) && (sbt < tick_sbt))
+ sbintime_t pr;
+
+ if ((coa.flags & C_HARDCLOCK) && (sbt < tick_sbt))
sbt = tick_sbt;
- if ((flags & C_HARDCLOCK) ||
+ if ((coa.flags & C_HARDCLOCK) ||
#ifdef NO_EVENTTIMERS
sbt >= sbt_timethreshold) {
- to_sbt = getsbinuptime();
+ coa.time = getsbinuptime();
/* Add safety belt for the case of hz > 1000. */
- to_sbt += tc_tick_sbt - tick_sbt;
+ coa.time += tc_tick_sbt - tick_sbt;
#else
sbt >= sbt_tickthreshold) {
/*
@@ -966,142 +1189,29 @@
* active ones.
*/
#ifdef __LP64__
- to_sbt = DPCPU_GET(hardclocktime);
+ coa.time = DPCPU_GET(hardclocktime);
#else
spinlock_enter();
- to_sbt = DPCPU_GET(hardclocktime);
+ coa.time = DPCPU_GET(hardclocktime);
spinlock_exit();
#endif
#endif
- if ((flags & C_HARDCLOCK) == 0)
- to_sbt += tick_sbt;
+ if ((coa.flags & C_HARDCLOCK) == 0)
+ coa.time += tick_sbt;
} else
- to_sbt = sbinuptime();
- if (SBT_MAX - to_sbt < sbt)
- to_sbt = SBT_MAX;
+ coa.time = sbinuptime();
+ if (SBT_MAX - coa.time < sbt)
+ coa.time = SBT_MAX;
else
- to_sbt += sbt;
- pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp :
- sbt >> C_PRELGET(flags));
- if (pr > precision)
- precision = pr;
+ coa.time += sbt;
+ pr = ((C_PRELGET(coa.flags) < 0) ? sbt >> tc_precexp :
+ sbt >> C_PRELGET(coa.flags));
+ if (pr > coa.precision)
+ coa.precision = pr;
}
- /*
- * Don't allow migration of pre-allocated callouts lest they
- * become unbalanced.
- */
- if (c->c_flags & CALLOUT_LOCAL_ALLOC)
- cpu = c->c_cpu;
- /*
- * This flag used to be added by callout_cc_add, but the
- * first time you call this we could end up with the
- * wrong direct flag if we don't do it before we add.
- */
- if (flags & C_DIRECT_EXEC) {
- c->c_flags |= CALLOUT_DIRECT;
- }
- direct = (c->c_flags & CALLOUT_DIRECT) != 0;
- KASSERT(!direct || c->c_lock == NULL,
- ("%s: direct callout %p has lock", __func__, c));
- cc = callout_lock(c);
- if (cc_exec_curr(cc, direct) == c) {
- /*
- * We're being asked to reschedule a callout which is
- * currently in progress. If there is a lock then we
- * can cancel the callout if it has not really started.
- */
- if (c->c_lock != NULL && cc_exec_cancel(cc, direct))
- cancelled = cc_exec_cancel(cc, direct) = true;
- if (cc_exec_waiting(cc, direct)) {
- /*
- * Someone has called callout_drain to kill this
- * callout. Don't reschedule.
- */
- CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
- cancelled ? "cancelled" : "failed to cancel",
- c, c->c_func, c->c_arg);
- CC_UNLOCK(cc);
- return (cancelled);
- }
-#ifdef SMP
- if (callout_migrating(c)) {
- /*
- * This only occurs when a second callout_reset_sbt_on
- * is made after a previous one moved it into
- * deferred migration (below). Note we do *not* change
- * the prev_cpu even though the previous target may
- * be different.
- */
- cc_migration_cpu(cc, direct) = cpu;
- cc_migration_time(cc, direct) = to_sbt;
- cc_migration_prec(cc, direct) = precision;
- cc_migration_func(cc, direct) = ftn;
- cc_migration_arg(cc, direct) = arg;
- cancelled = 1;
- CC_UNLOCK(cc);
- return (cancelled);
- }
-#endif
- }
- if (c->c_flags & CALLOUT_PENDING) {
- if ((c->c_flags & CALLOUT_PROCESSED) == 0) {
- if (cc_exec_next(cc) == c)
- cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
- LIST_REMOVE(c, c_links.le);
- } else
- TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
- cancelled = 1;
- c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
- }
-
-#ifdef SMP
- /*
- * If the callout must migrate try to perform it immediately.
- * If the callout is currently running, just defer the migration
- * to a more appropriate moment.
- */
- if (c->c_cpu != cpu) {
- if (cc_exec_curr(cc, direct) == c) {
- /*
- * Pending will have been removed since we are
- * actually executing the callout on another
- * CPU. That callout should be waiting on the
- * lock the caller holds. If we set both
- * active/and/pending after we return and the
- * lock on the executing callout proceeds, it
- * will then see pending is true and return.
- * At the return from the actual callout execution
- * the migration will occur in softclock_call_cc
- * and this new callout will be placed on the
- * new CPU via a call to callout_cpu_switch() which
- * will get the lock on the right CPU followed
- * by a call callout_cc_add() which will add it there.
- * (see above in softclock_call_cc()).
- */
- cc_migration_cpu(cc, direct) = cpu;
- cc_migration_time(cc, direct) = to_sbt;
- cc_migration_prec(cc, direct) = precision;
- cc_migration_func(cc, direct) = ftn;
- cc_migration_arg(cc, direct) = arg;
- c->c_flags |= (CALLOUT_DFRMIGRATION | CALLOUT_ACTIVE | CALLOUT_PENDING);
- CTR6(KTR_CALLOUT,
- "migration of %p func %p arg %p in %d.%08x to %u deferred",
- c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
- (u_int)(to_sbt & 0xffffffff), cpu);
- CC_UNLOCK(cc);
- return (cancelled);
- }
- cc = callout_cpu_switch(c, cc, cpu);
- }
-#endif
- callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags);
- CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x",
- cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
- (u_int)(to_sbt & 0xffffffff));
- CC_UNLOCK(cc);
-
- return (cancelled);
+ /* get callback started, if any */
+ return (callout_restart_async(c, &coa, NULL, NULL));
}
/*
@@ -1120,252 +1230,106 @@
}
int
-_callout_stop_safe(struct callout *c, int safe)
+callout_stop(struct callout *c)
{
- struct callout_cpu *cc, *old_cc;
- struct lock_class *class;
- int direct, sq_locked, use_lock;
- int not_on_a_list;
-
- if (safe)
- WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock,
- "calling %s", __func__);
+ /* get callback stopped, if any */
+ return (callout_restart_async(c, NULL, NULL, NULL));
+}
- /*
- * Some old subsystems don't hold Giant while running a callout_stop(),
- * so just discard this check for the moment.
- */
- if (!safe && c->c_lock != NULL) {
- if (c->c_lock == &Giant.lock_object)
- use_lock = mtx_owned(&Giant);
- else {
- use_lock = 1;
- class = LOCK_CLASS(c->c_lock);
- class->lc_assert(c->c_lock, LA_XLOCKED);
- }
- } else
- use_lock = 0;
- direct = (c->c_flags & CALLOUT_DIRECT) != 0;
- sq_locked = 0;
- old_cc = NULL;
-again:
- cc = callout_lock(c);
+static void
+callout_drain_function(void *arg)
+{
+ wakeup(arg);
+}
- if ((c->c_flags & (CALLOUT_DFRMIGRATION | CALLOUT_ACTIVE | CALLOUT_PENDING)) ==
- (CALLOUT_DFRMIGRATION | CALLOUT_ACTIVE | CALLOUT_PENDING)) {
- /*
- * Special case where this slipped in while we
- * were migrating *as* the callout is about to
- * execute. The caller probably holds the lock
- * the callout wants.
- *
- * Get rid of the migration first. Then set
- * the flag that tells this code *not* to
- * try to remove it from any lists (its not
- * on one yet). When the callout wheel runs,
- * it will ignore this callout.
- */
- c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_ACTIVE);
- not_on_a_list = 1;
- } else {
- not_on_a_list = 0;
- }
+int
+callout_drain_async(struct callout *c, callout_func_t *fn, void *arg)
+{
+ /* get callback stopped, if any */
+ return (callout_restart_async(
+ c, NULL, fn, arg) & CALLOUT_RET_DRAINING);
+}
- /*
- * If the callout was migrating while the callout cpu lock was
- * dropped, just drop the sleepqueue lock and check the states
- * again.
- */
- if (sq_locked != 0 && cc != old_cc) {
-#ifdef SMP
- CC_UNLOCK(cc);
- sleepq_release(&cc_exec_waiting(old_cc, direct));
- sq_locked = 0;
- old_cc = NULL;
- goto again;
-#else
- panic("migration should not happen");
-#endif
- }
+int
+callout_drain(struct callout *c)
+{
+ int cancelled;
- /*
- * If the callout isn't pending, it's not on the queue, so
- * don't attempt to remove it from the queue. We can try to
- * stop it by other means however.
- */
- if (!(c->c_flags & CALLOUT_PENDING)) {
- c->c_flags &= ~CALLOUT_ACTIVE;
+ WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
+ "Draining callout");
+
+ callout_lock_client(c->c_flags, c->c_lock);
+
+ /* at this point the "c->c_cpu" field is not changing */
+
+ cancelled = callout_drain_async(c, &callout_drain_function, c);
+
+ if (cancelled != CALLOUT_RET_NORMAL) {
+ struct callout_cpu *cc;
+ int direct;
+
+ CTR3(KTR_CALLOUT, "need to drain %p func %p arg %p",
+ c, c->c_func, c->c_arg);
+
+ cc = callout_lock(c);
+ direct = ((c->c_flags & CALLOUT_DIRECT) != 0);
/*
- * If it wasn't on the queue and it isn't the current
- * callout, then we can't stop it, so just bail.
+ * We've gotten our callout CPU lock, it is safe to
+ * drop the initial lock:
*/
- if (cc_exec_curr(cc, direct) != c) {
- CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
- c, c->c_func, c->c_arg);
- CC_UNLOCK(cc);
- if (sq_locked)
- sleepq_release(&cc_exec_waiting(cc, direct));
- return (0);
- }
+ callout_unlock_client(c->c_flags, c->c_lock);
- if (safe) {
- /*
- * The current callout is running (or just
- * about to run) and blocking is allowed, so
- * just wait for the current invocation to
- * finish.
- */
- while (cc_exec_curr(cc, direct) == c) {
- /*
- * Use direct calls to sleepqueue interface
- * instead of cv/msleep in order to avoid
- * a LOR between cc_lock and sleepqueue
- * chain spinlocks. This piece of code
- * emulates a msleep_spin() call actually.
- *
- * If we already have the sleepqueue chain
- * locked, then we can safely block. If we
- * don't already have it locked, however,
- * we have to drop the cc_lock to lock
- * it. This opens several races, so we
- * restart at the beginning once we have
- * both locks. If nothing has changed, then
- * we will end up back here with sq_locked
- * set.
- */
- if (!sq_locked) {
- CC_UNLOCK(cc);
- sleepq_lock(
- &cc_exec_waiting(cc, direct));
- sq_locked = 1;
- old_cc = cc;
- goto again;
- }
+ /* Wait for drain to complete */
+
+ while (cc_exec_curr(cc, direct) == c)
+ msleep_spin(c, (struct mtx *)&cc->cc_lock, "codrain", 0);
- /*
- * Migration could be cancelled here, but
- * as long as it is still not sure when it
- * will be packed up, just let softclock()
- * take care of it.
- */
- cc_exec_waiting(cc, direct) = true;
- DROP_GIANT();
- CC_UNLOCK(cc);
- sleepq_add(
- &cc_exec_waiting(cc, direct),
- &cc->cc_lock.lock_object, "codrain",
- SLEEPQ_SLEEP, 0);
- sleepq_wait(
- &cc_exec_waiting(cc, direct),
- 0);
- sq_locked = 0;
- old_cc = NULL;
-
- /* Reacquire locks previously released. */
- PICKUP_GIANT();
- CC_LOCK(cc);
- }
- } else if (use_lock &&
- !cc_exec_cancel(cc, direct)) {
-
- /*
- * The current callout is waiting for its
- * lock which we hold. Cancel the callout
- * and return. After our caller drops the
- * lock, the callout will be skipped in
- * softclock().
- */
- cc_exec_cancel(cc, direct) = true;
- CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
- c, c->c_func, c->c_arg);
- KASSERT(!cc_cce_migrating(cc, direct),
- ("callout wrongly scheduled for migration"));
- CC_UNLOCK(cc);
- KASSERT(!sq_locked, ("sleepqueue chain locked"));
- return (1);
- } else if (callout_migrating(c)) {
- /*
- * The callout is currently being serviced
- * and the "next" callout is scheduled at
- * its completion with a migration. We remove
- * the migration flag so it *won't* get rescheduled,
- * but we can't stop the one thats running so
- * we return 0.
- */
- c->c_flags &= ~CALLOUT_DFRMIGRATION;
-#ifdef SMP
- /*
- * We can't call cc_cce_cleanup here since
- * if we do it will remove .ce_curr and
- * its still running. This will prevent a
- * reschedule of the callout when the
- * execution completes.
- */
- cc_migration_cpu(cc, direct) = CPUBLOCK;
- cc_migration_time(cc, direct) = 0;
- cc_migration_prec(cc, direct) = 0;
- cc_migration_func(cc, direct) = NULL;
- cc_migration_arg(cc, direct) = NULL;
-#endif
- CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p",
- c, c->c_func, c->c_arg);
- CC_UNLOCK(cc);
- return (0);
- }
- CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
- c, c->c_func, c->c_arg);
CC_UNLOCK(cc);
- KASSERT(!sq_locked, ("sleepqueue chain still locked"));
- return (0);
+ } else {
+ callout_unlock_client(c->c_flags, c->c_lock);
}
- if (sq_locked)
- sleepq_release(&cc_exec_waiting(cc, direct));
-
- c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
c, c->c_func, c->c_arg);
- if (not_on_a_list == 0) {
- if ((c->c_flags & CALLOUT_PROCESSED) == 0) {
- if (cc_exec_next(cc) == c)
- cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
- LIST_REMOVE(c, c_links.le);
- } else
- TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
- }
- callout_cc_del(c, cc);
- CC_UNLOCK(cc);
- return (1);
+
+ return (cancelled & CALLOUT_RET_CANCELLED);
}
void
callout_init(struct callout *c, int mpsafe)
{
- bzero(c, sizeof *c);
if (mpsafe) {
- c->c_lock = NULL;
- c->c_flags = CALLOUT_RETURNUNLOCKED;
+ _callout_init_lock(c, NULL, CALLOUT_RETURNUNLOCKED);
} else {
- c->c_lock = &Giant.lock_object;
- c->c_flags = 0;
+ _callout_init_lock(c, &Giant.lock_object, 0);
}
- c->c_cpu = timeout_cpu;
}
void
_callout_init_lock(struct callout *c, struct lock_object *lock, int flags)
{
bzero(c, sizeof *c);
+ KASSERT((flags & ~CALLOUT_RETURNUNLOCKED) == 0,
+ ("callout_init_lock: bad flags 0x%08x", flags));
+ flags &= CALLOUT_RETURNUNLOCKED;
+ if (lock != NULL) {
+ struct lock_class *class = LOCK_CLASS(lock);
+ if (class == &lock_class_mtx_sleep)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_MUTEX);
+ else if (class == &lock_class_mtx_spin)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_SPIN);
+ else if (class == &lock_class_rm)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_RM);
+ else if (class == &lock_class_rw)
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_RW);
+ else
+ panic("callout_init_lock: Unsupported lock class '%s'\n", class->lc_name);
+ } else {
+ flags |= CALLOUT_SET_LC(CALLOUT_LC_UNUSED_0);
+ }
c->c_lock = lock;
- KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0,
- ("callout_init_lock: bad flags %d", flags));
- KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0,
- ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock"));
- KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags &
- (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class",
- __func__));
- c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK);
+ c->c_flags = flags;
c->c_cpu = timeout_cpu;
}
Index: sys/kern/subr_sleepqueue.c
===================================================================
--- sys/kern/subr_sleepqueue.c
+++ sys/kern/subr_sleepqueue.c
@@ -152,7 +152,8 @@
*/
static int sleepq_catch_signals(void *wchan, int pri);
static int sleepq_check_signals(void);
-static int sleepq_check_timeout(void);
+static int sleepq_check_timeout(struct thread *);
+static void sleepq_stop_timeout(struct thread *);
#ifdef INVARIANTS
static void sleepq_dtor(void *mem, int size, void *arg);
#endif
@@ -373,17 +374,14 @@
sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt, sbintime_t pr,
int flags)
{
- struct sleepqueue_chain *sc;
struct thread *td;
td = curthread;
- sc = SC_LOOKUP(wchan);
- mtx_assert(&sc->sc_lock, MA_OWNED);
- MPASS(TD_ON_SLEEPQ(td));
- MPASS(td->td_sleepqueue == NULL);
- MPASS(wchan != NULL);
+
+ mtx_lock_spin(&td->td_slpmutex);
callout_reset_sbt_on(&td->td_slpcallout, sbt, pr,
sleepq_timeout, td, PCPU_GET(cpuid), flags | C_DIRECT_EXEC);
+ mtx_unlock_spin(&td->td_slpmutex);
}
/*
@@ -559,11 +557,8 @@
* Check to see if we timed out.
*/
static int
-sleepq_check_timeout(void)
+sleepq_check_timeout(struct thread *td)
{
- struct thread *td;
-
- td = curthread;
THREAD_LOCK_ASSERT(td, MA_OWNED);
/*
@@ -573,28 +568,21 @@
td->td_flags &= ~TDF_TIMEOUT;
return (EWOULDBLOCK);
}
-
- /*
- * If TDF_TIMOFAIL is set, the timeout ran after we had
- * already been woken up.
- */
- if (td->td_flags & TDF_TIMOFAIL)
- td->td_flags &= ~TDF_TIMOFAIL;
-
- /*
- * If callout_stop() fails, then the timeout is running on
- * another CPU, so synchronize with it to avoid having it
- * accidentally wake up a subsequent sleep.
- */
- else if (callout_stop(&td->td_slpcallout) == 0) {
- td->td_flags |= TDF_TIMEOUT;
- TD_SET_SLEEPING(td);
- mi_switch(SW_INVOL | SWT_SLEEPQTIMO, NULL);
- }
return (0);
}
/*
+ * Atomically stop the timeout by using a mutex.
+ */
+static void
+sleepq_stop_timeout(struct thread *td)
+{
+ mtx_lock_spin(&td->td_slpmutex);
+ callout_stop(&td->td_slpcallout);
+ mtx_unlock_spin(&td->td_slpmutex);
+}
+
+/*
* Check to see if we were awoken by a signal.
*/
static int
@@ -664,9 +652,11 @@
MPASS(!(td->td_flags & TDF_SINTR));
thread_lock(td);
sleepq_switch(wchan, pri);
- rval = sleepq_check_timeout();
+ rval = sleepq_check_timeout(td);
thread_unlock(td);
+ sleepq_stop_timeout(td);
+
return (rval);
}
@@ -677,12 +667,18 @@
int
sleepq_timedwait_sig(void *wchan, int pri)
{
+ struct thread *td;
int rcatch, rvalt, rvals;
+ td = curthread;
+
rcatch = sleepq_catch_signals(wchan, pri);
- rvalt = sleepq_check_timeout();
+ rvalt = sleepq_check_timeout(td);
rvals = sleepq_check_signals();
- thread_unlock(curthread);
+ thread_unlock(td);
+
+ sleepq_stop_timeout(td);
+
if (rcatch)
return (rcatch);
if (rvals)
@@ -889,64 +885,49 @@
static void
sleepq_timeout(void *arg)
{
- struct sleepqueue_chain *sc;
- struct sleepqueue *sq;
- struct thread *td;
- void *wchan;
- int wakeup_swapper;
+ struct thread *td = arg;
+ int wakeup_swapper = 0;
- td = arg;
- wakeup_swapper = 0;
CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)",
(void *)td, (long)td->td_proc->p_pid, (void *)td->td_name);
- /*
- * First, see if the thread is asleep and get the wait channel if
- * it is.
- */
- thread_lock(td);
- if (TD_IS_SLEEPING(td) && TD_ON_SLEEPQ(td)) {
- wchan = td->td_wchan;
- sc = SC_LOOKUP(wchan);
- THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock);
- sq = sleepq_lookup(wchan);
- MPASS(sq != NULL);
- td->td_flags |= TDF_TIMEOUT;
- wakeup_swapper = sleepq_resume_thread(sq, td, 0);
- thread_unlock(td);
- if (wakeup_swapper)
- kick_proc0();
- return;
- }
+ /* Handle the three cases which can happen */
- /*
- * If the thread is on the SLEEPQ but isn't sleeping yet, it
- * can either be on another CPU in between sleepq_add() and
- * one of the sleepq_*wait*() routines or it can be in
- * sleepq_catch_signals().
- */
+ thread_lock(td);
if (TD_ON_SLEEPQ(td)) {
- td->td_flags |= TDF_TIMEOUT;
- thread_unlock(td);
- return;
- }
+ if (TD_IS_SLEEPING(td)) {
+ struct sleepqueue_chain *sc;
+ struct sleepqueue *sq;
+ void *wchan;
- /*
- * Now check for the edge cases. First, if TDF_TIMEOUT is set,
- * then the other thread has already yielded to us, so clear
- * the flag and resume it. If TDF_TIMEOUT is not set, then the
- * we know that the other thread is not on a sleep queue, but it
- * hasn't resumed execution yet. In that case, set TDF_TIMOFAIL
- * to let it know that the timeout has already run and doesn't
- * need to be canceled.
- */
- if (td->td_flags & TDF_TIMEOUT) {
- MPASS(TD_IS_SLEEPING(td));
- td->td_flags &= ~TDF_TIMEOUT;
- TD_CLR_SLEEPING(td);
- wakeup_swapper = setrunnable(td);
- } else
- td->td_flags |= TDF_TIMOFAIL;
+ /*
+ * Case I - thread is asleep and needs to be
+ * awoken:
+ */
+ wchan = td->td_wchan;
+ sc = SC_LOOKUP(wchan);
+ THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock);
+ sq = sleepq_lookup(wchan);
+ MPASS(sq != NULL);
+ td->td_flags |= TDF_TIMEOUT;
+ wakeup_swapper = sleepq_resume_thread(sq, td, 0);
+ } else {
+ /*
+ * Case II - cancel going to sleep by setting
+ * the timeout flag because the target thread
+ * is not asleep yet. It can be on another CPU
+ * in between sleepq_add() and one of the
+ * sleepq_*wait*() routines or it can be in
+ * sleepq_catch_signals().
+ */
+ td->td_flags |= TDF_TIMEOUT;
+ }
+ } else {
+ /*
+ * Case III - thread is already woken up by a wakeup
+ * call and should not timeout. Nothing to do!
+ */
+ }
thread_unlock(td);
if (wakeup_swapper)
kick_proc0();
Index: sys/ofed/include/linux/completion.h
===================================================================
--- sys/ofed/include/linux/completion.h
+++ sys/ofed/include/linux/completion.h
@@ -105,7 +105,9 @@
if (c->done)
break;
sleepq_add(c, NULL, "completion", flags, 0);
+ sleepq_release(c);
sleepq_set_timeout(c, end - ticks);
+ sleepq_lock(c);
if (flags & SLEEPQ_INTERRUPTIBLE) {
if (sleepq_timedwait_sig(c, 0) != 0)
return (-ERESTARTSYS);
Index: sys/sys/_callout.h
===================================================================
--- sys/sys/_callout.h
+++ sys/sys/_callout.h
@@ -46,6 +46,8 @@
SLIST_HEAD(callout_slist, callout);
TAILQ_HEAD(callout_tailq, callout);
+typedef void callout_func_t(void *);
+
struct callout {
union {
LIST_ENTRY(callout) le;
@@ -55,7 +57,7 @@
sbintime_t c_time; /* ticks to the event */
sbintime_t c_precision; /* delta allowed wrt opt */
void *c_arg; /* function argument */
- void (*c_func)(void *); /* function to call */
+ callout_func_t *c_func; /* function to call */
struct lock_object *c_lock; /* lock to handle */
int c_flags; /* state of this entry */
volatile int c_cpu; /* CPU we're scheduled on */
Index: sys/sys/callout.h
===================================================================
--- sys/sys/callout.h
+++ sys/sys/callout.h
@@ -45,10 +45,12 @@
#define CALLOUT_PENDING 0x0004 /* callout is waiting for timeout */
#define CALLOUT_MPSAFE 0x0008 /* callout handler is mp safe */
#define CALLOUT_RETURNUNLOCKED 0x0010 /* handler returns with mtx unlocked */
-#define CALLOUT_SHAREDLOCK 0x0020 /* callout lock held in shared mode */
-#define CALLOUT_DFRMIGRATION 0x0040 /* callout in deferred migration mode */
+#define CALLOUT_UNUSED_5 0x0020 /* --available-- */
+#define CALLOUT_DEFRESTART 0x0040 /* callout restart is deferred */
#define CALLOUT_PROCESSED 0x0080 /* callout in wheel or processing list? */
#define CALLOUT_DIRECT 0x0100 /* allow exec from hw int context */
+#define CALLOUT_SET_LC(x) (((x) & 7) << 16) /* set lock class */
+#define CALLOUT_GET_LC(x) (((x) >> 16) & 7) /* get lock class */
#define C_DIRECT_EXEC 0x0001 /* direct execution of callout */
#define C_PRELBITS 7
@@ -64,9 +66,9 @@
#ifdef _KERNEL
#define callout_active(c) ((c)->c_flags & CALLOUT_ACTIVE)
-#define callout_migrating(c) ((c)->c_flags & CALLOUT_DFRMIGRATION)
#define callout_deactivate(c) ((c)->c_flags &= ~CALLOUT_ACTIVE)
-#define callout_drain(c) _callout_stop_safe(c, 1)
+int callout_drain(struct callout *);
+int callout_drain_async(struct callout *, callout_func_t *, void *);
void callout_init(struct callout *, int);
void _callout_init_lock(struct callout *, struct lock_object *, int);
#define callout_init_mtx(c, mtx, flags) \
@@ -80,7 +82,7 @@
NULL, (flags))
#define callout_pending(c) ((c)->c_flags & CALLOUT_PENDING)
int callout_reset_sbt_on(struct callout *, sbintime_t, sbintime_t,
- void (*)(void *), void *, int, int);
+ callout_func_t *, void *, int, int);
#define callout_reset_sbt(c, sbt, pr, fn, arg, flags) \
callout_reset_sbt_on((c), (sbt), (pr), (fn), (arg), (c)->c_cpu, (flags))
#define callout_reset_sbt_curcpu(c, sbt, pr, fn, arg, flags) \
@@ -104,8 +106,7 @@
int callout_schedule_on(struct callout *, int, int);
#define callout_schedule_curcpu(c, on_tick) \
callout_schedule_on((c), (on_tick), PCPU_GET(cpuid))
-#define callout_stop(c) _callout_stop_safe(c, 0)
-int _callout_stop_safe(struct callout *, int);
+int callout_stop(struct callout *);
void callout_process(sbintime_t now);
#endif
Index: sys/sys/proc.h
===================================================================
--- sys/sys/proc.h
+++ sys/sys/proc.h
@@ -308,6 +308,7 @@
} td_uretoff; /* (k) Syscall aux returns. */
#define td_retval td_uretoff.tdu_retval
struct callout td_slpcallout; /* (h) Callout for sleep. */
+ struct mtx td_slpmutex; /* (h) Mutex for sleep callout */
struct trapframe *td_frame; /* (k) */
struct vm_object *td_kstack_obj;/* (a) Kstack object. */
vm_offset_t td_kstack; /* (a) Kernel VA of kstack. */
@@ -364,7 +365,7 @@
#define TDF_ALLPROCSUSP 0x00000200 /* suspended by SINGLE_ALLPROC */
#define TDF_BOUNDARY 0x00000400 /* Thread suspended at user boundary */
#define TDF_ASTPENDING 0x00000800 /* Thread has some asynchronous events. */
-#define TDF_TIMOFAIL 0x00001000 /* Timeout from sleep after we were awake. */
+#define TDF_UNUSED12 0x00001000 /* --available-- */
#define TDF_SBDRY 0x00002000 /* Stop only on usermode boundary. */
#define TDF_UPIBLOCKED 0x00004000 /* Thread blocked on user PI mutex. */
#define TDF_NEEDSUSPCHK 0x00008000 /* Thread may need to suspend. */
@@ -706,7 +707,7 @@
#define SWT_OWEPREEMPT 2 /* Switching due to opepreempt. */
#define SWT_TURNSTILE 3 /* Turnstile contention. */
#define SWT_SLEEPQ 4 /* Sleepq wait. */
-#define SWT_SLEEPQTIMO 5 /* Sleepq timeout wait. */
+#define SWT_UNUSED5 5 /* --available-- */
#define SWT_RELINQUISH 6 /* yield call. */
#define SWT_NEEDRESCHED 7 /* NEEDRESCHED was set. */
#define SWT_IDLE 8 /* Switching from the idle thread. */

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