Index: head/share/man/man9/timeout.9 =================================================================== --- head/share/man/man9/timeout.9 (revision 302349) +++ head/share/man/man9/timeout.9 (revision 302350) @@ -1,848 +1,852 @@ .\" $NetBSD: timeout.9,v 1.2 1996/06/23 22:32:34 pk Exp $ .\" .\" Copyright (c) 1996 The NetBSD Foundation, Inc. .\" All rights reserved. .\" .\" This code is derived from software contributed to The NetBSD Foundation .\" by Paul Kranenburg. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE .\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" .\" $FreeBSD$ .\" -.Dd September 14, 2015 +.Dd July 4, 2016 .Dt TIMEOUT 9 .Os .Sh NAME .Nm callout_active , .Nm callout_deactivate , .Nm callout_async_drain , .Nm callout_drain , .Nm callout_handle_init , .Nm callout_init , .Nm callout_init_mtx , .Nm callout_init_rm , .Nm callout_init_rw , .Nm callout_pending , .Nm callout_reset , .Nm callout_reset_curcpu , .Nm callout_reset_on , .Nm callout_reset_sbt , .Nm callout_reset_sbt_curcpu , .Nm callout_reset_sbt_on , .Nm callout_schedule , .Nm callout_schedule_curcpu , .Nm callout_schedule_on , .Nm callout_schedule_sbt , .Nm callout_schedule_sbt_curcpu , .Nm callout_schedule_sbt_on , .Nm callout_stop , .Nm timeout , .Nm untimeout .Nd execute a function after a specified length of time .Sh SYNOPSIS .In sys/types.h .In sys/systm.h .Bd -literal typedef void timeout_t (void *); .Ed .Ft int .Fn callout_active "struct callout *c" .Ft void .Fn callout_deactivate "struct callout *c" .Ft int .Fn callout_async_drain "struct callout *c" "timeout_t *drain" .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 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 .Fn callout_init function initializes a callout structure in .Fa c that is not associated with a specific lock. 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. .Pp These .Fa flags may be specified for .Fn callout_init_mtx , .Fn callout_init_rm , or .Fn callout_init_rw : .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 . .El .Pp The function .Fn callout_stop cancels a callout .Fa c if it is currently pending. If the callout is pending and successfully stopped, then .Fn callout_stop returns a value of one. If the callout is not set, or has already been serviced, then negative one is returned. If the callout is currently being serviced and cannot be stopped, then zero will be returned. +If the callout is currently being serviced and cannot be stopped, and at the +same time a next invocation of the same callout is also scheduled, then +.Fn callout_stop +unschedules the next run and returns zero. If the callout has an associated lock, then that lock must be held when this function is called. .Pp The function .Fn callout_async_drain is identical to .Fn callout_stop with one difference. When .Fn callout_async_drain returns zero it will arrange for the function .Fa drain to be called using the same argument given to the .Fn callout_reset function. .Fn callout_async_drain If the callout has an associated lock, then that lock must be held when this function is called. Note that when stopping multiple callouts that use the same lock it is possible to get multiple return's of zero and multiple calls to the .Fa drain function, depending upon which CPU's the callouts are running. The .Fa drain function itself is called from the context of the completing callout i.e. softclock or hardclock, just like a callout itself. p .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. .Pp The .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 value of one 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 .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 sbt and extends for the amount of time specified in .Fa pr . If .Fa sbt specifies a time in the past, the window is adjusted to start at the current time. A non-zero value for .Fa pr allows the callout subsystem to coalesce callouts scheduled close to each other into fewer timer interrupts, reducing processing overhead and power consumption. These .Fa flags may be specified to adjust the interpretation of .Fa sbt and .Fa pr : .Bl -tag -width ".Dv C_DIRECT_EXEC" .It Dv C_ABSOLUTE Handle the .Fa sbt argument as an absolute time since boot. By default, .Fa sbt is treated as a relative amount of time, similar to .Fa ticks . .It Dv C_DIRECT_EXEC Run the handler directly from hardware interrupt context instead of from the softclock thread. This reduces latency and overhead, but puts more constraints on the callout function. Callout functions run in this context may use only spin mutexes for locking 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. Note that the larger of .Fa pr or this value is used as the length of the time window. Smaller values .Pq which result in larger time intervals allow the callout subsystem to aggregate more events in one timer interrupt. .It Dv C_HARDCLOCK Align the timeouts to .Fn hardclock calls if possible. .El .Pp The .Fn callout_reset functions accept a .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, .Fa func will receive .Fa arg as its only argument. The .Fn callout_schedule functions reuse the .Fa func and .Fa arg arguments from the previous callout. Note that one of the .Fn callout_reset functions must always be called to initialize .Fa func and .Fa arg before one of the .Fn callout_schedule functions can be used. .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. .Pp 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 loader tunable to a non-zero value. Softclock threads for CPUs other than zero can be pinned to their 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" The callout subsystem invokes callout functions from its own thread context. Without some kind of synchronization, it is possible that a callout function will be invoked concurrently with an attempt to stop or reset the callout by another thread. In particular, since callout functions typically acquire a lock as their first action, the callout function may have already been invoked, but is blocked waiting for that lock at the time that another thread tries to reset or stop the callout. .Pp There are three main techniques for addressing these synchronization concerns. The first approach is preferred as it is the simplest: .Bl -enum -offset indent .It Callouts can be associated with a specific lock when they are initialized by .Fn callout_init_mtx , .Fn callout_init_rm , or .Fn callout_init_rw . When a callout is associated with a lock, the callout subsystem acquires the lock before the callout function is invoked. This allows the callout subsystem to transparently handle races between callout cancellation, scheduling, and execution. Note that the associated lock must be acquired before calling .Fn callout_stop or one of the .Fn callout_reset or .Fn callout_schedule functions to provide this safety. .Pp A callout initialized via .Fn callout_init with .Fa mpsafe set to zero is implicitly associated with the .Va Giant mutex. If .Va Giant is held when cancelling or rescheduling the callout, then its use will prevent races with the callout function. .It The return value from .Fn callout_stop .Po or the .Fn callout_reset and .Fn callout_schedule function families .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. For example: .Bd -literal -offset indent if (sc->sc_flags & SCFLG_CALLOUT_RUNNING) { if (callout_stop(&sc->sc_callout)) { sc->sc_flags &= ~SCFLG_CALLOUT_RUNNING; /* successfully stopped */ } else { /* * callout has expired and callout * function is about to be executed */ } } .Ed .It The .Fn callout_pending , .Fn callout_active and .Fn callout_deactivate macros can be used together to work around the race conditions. When a callout's timeout is set, the callout subsystem marks the callout as both .Em active and .Em pending . When the timeout time arrives, the callout subsystem begins processing the callout by first clearing the .Em pending flag. It then invokes the callout function without changing the .Em active flag, and does not clear the .Em active flag even after the callout function returns. The mechanism described here requires the callout function itself to clear the .Em active flag using the .Fn callout_deactivate macro. The .Fn callout_stop and .Fn callout_drain functions always clear both the .Em active and .Em pending flags before returning. .Pp The callout function should first check the .Em pending flag and return without action if .Fn callout_pending returns .Dv TRUE . 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. This indicates that the callout has been stopped. Finally, the callout function should call .Fn callout_deactivate to clear the .Em active flag. For example: .Bd -literal -offset indent mtx_lock(&sc->sc_mtx); if (callout_pending(&sc->sc_callout)) { /* callout was reset */ mtx_unlock(&sc->sc_mtx); return; } if (!callout_active(&sc->sc_callout)) { /* callout was stopped */ mtx_unlock(&sc->sc_mtx); return; } callout_deactivate(&sc->sc_callout); /* rest of callout function */ .Ed .Pp Together with appropriate synchronization, such as the mutex used above, this approach permits the .Fn callout_stop and .Fn callout_reset functions to be used at any time without races. For example: .Bd -literal -offset indent mtx_lock(&sc->sc_mtx); callout_stop(&sc->sc_callout); /* The callout is effectively stopped now. */ .Ed .Pp If the callout is still pending then these functions operate normally, but if processing of the callout has already begun then the tests in the callout function cause it to return without further action. Synchronization between the callout function and other code ensures that stopping or resetting the callout will never be attempted while the callout function is past the .Fn callout_deactivate call. .Pp The above technique additionally ensures that the .Em active flag always reflects whether the callout is effectively enabled or disabled. If .Fn callout_active returns false, then the callout is effectively disabled, since even if the callout subsystem is actually just about to invoke the callout function, the callout function will return without action. .El .Pp There is one final race condition that must be considered when a callout is being stopped for the last time. In this case it may not be safe to let the callout function itself detect that the callout was stopped, since it may need to access data objects that have already been destroyed or recycled. To ensure that the callout is completely finished, a call to .Fn callout_drain should be used. In particular, a callout should always be drained prior to destroying its associated lock 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 .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 a value of one if the callout was pending before the new function invocation was scheduled. .Pp The .Fn callout_stop and .Fn callout_drain functions return a value of one if the callout was still pending when it was called, a zero if the callout could not be stopped and a negative one is it -was either not running or haas already completed. +was either not running or has already completed. The .Fn timeout function returns a .Ft struct callout_handle that can be passed to .Fn untimeout . .Sh HISTORY The current timeout and untimeout routines are based on the work of .An Adam M. Costello and .An George Varghese , published in a technical report entitled .%T "Redesigning the BSD Callout and Timer Facilities" and modified slightly for inclusion in .Fx by .An Justin T. Gibbs . The original work on the data structures used in this implementation was published by .An G. Varghese and .An A. Lauck in the paper .%T "Hashed and Hierarchical Timing Wheels: Data Structures for the Efficient Implementation of a Timer Facility" in the .%B "Proceedings of the 11th ACM Annual Symposium on Operating Systems Principles" . The current implementation replaces the long standing .Bx linked list callout mechanism which offered O(n) insertion and removal running time but did not generate or require handles for untimeout operations. Index: head/sys/kern/kern_timeout.c =================================================================== --- head/sys/kern/kern_timeout.c (revision 302349) +++ head/sys/kern/kern_timeout.c (revision 302350) @@ -1,1654 +1,1648 @@ /*- * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_callout_profiling.h" #include "opt_ddb.h" #if defined(__arm__) #include "opt_timer.h" #endif #include "opt_rss.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #include #endif #ifdef SMP #include #endif #ifndef NO_EVENTTIMERS DPCPU_DECLARE(sbintime_t, hardclocktime); #endif SDT_PROVIDER_DEFINE(callout_execute); SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); #ifdef CALLOUT_PROFILING static int avg_depth; SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 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, "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, "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, "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, "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 " "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, 0, "Average number of MP direct callouts made per callout_process call. " "Units = 1/1000"); #endif static int ncallout; SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, "Number of entries in callwheel and size of timeout() preallocation"); #ifdef RSS static int pin_default_swi = 1; static int pin_pcpu_swi = 1; #else static int pin_default_swi = 0; static int pin_pcpu_swi = 0; #endif SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 0, "Pin the per-CPU swis (except PCPU 0, which is also default"); /* * TODO: * allocate more timeout table slots when table overflows. */ u_int callwheelsize, callwheelmask; /* * 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. */ struct cc_exec { struct callout *cc_curr; void (*cc_drain)(void *); #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; #endif bool cc_cancel; bool cc_waiting; }; /* * 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_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_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain #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 CC_CPU(cpu) (&cc_cpu[(cpu)]) #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) #else struct callout_cpu cc_cpu; #define CC_CPU(cpu) &cc_cpu #define CC_SELF() &cc_cpu #endif #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 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 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. */ static void callout_callwheel_init(void *dummy) { struct callout_cpu *cc; /* * Calculate the size of the callout wheel and the preallocated * timeout() structures. * XXX: Clip callout to result of previous function of maxusers * maximum 384. This is still huge, but acceptable. */ memset(CC_CPU(0), 0, sizeof(cc_cpu)); ncallout = imin(16 + maxproc + maxfiles, 18508); TUNABLE_INT_FETCH("kern.ncallout", &ncallout); /* * Calculate callout wheel size, should be next power of two higher * than 'ncallout'. */ callwheelsize = 1 << fls(ncallout); callwheelmask = callwheelsize - 1; /* * Fetch whether we're pinning the swi's or not. */ TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); /* * Only cpu0 handles timeout(9) and receives a preallocation. * * XXX: Once all timeout(9) consumers are converted this can * be removed. */ timeout_cpu = PCPU_GET(cpuid); cc = CC_CPU(timeout_cpu); cc->cc_callout = malloc(ncallout * sizeof(struct callout), M_CALLOUT, M_WAITOK); callout_cpu_init(cc, timeout_cpu); } SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); /* * Initialize the per-cpu callout structures. */ static void callout_cpu_init(struct callout_cpu *cc, int cpu) { struct callout *c; int i; 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); 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) */ return; for (i = 0; i < ncallout; i++) { c = &cc->cc_callout[i]; callout_init(c, 0); c->c_iflags = 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) { struct callout_cpu *new_cc; MPASS(c != NULL && cc != NULL); CC_LOCK_ASSERT(cc); /* * 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); } #endif /* * Start standard softclock thread. */ static void start_softclock(void *dummy) { struct callout_cpu *cc; char name[MAXCOMLEN]; #ifdef SMP int cpu; struct intr_event *ie; #endif cc = CC_CPU(timeout_cpu); snprintf(name, sizeof(name), "clock (%d)", timeout_cpu); if (swi_add(&clk_intr_event, name, softclock, cc, SWI_CLOCK, INTR_MPSAFE, &cc->cc_cookie)) panic("died while creating standard software ithreads"); if (pin_default_swi && (intr_event_bind(clk_intr_event, timeout_cpu) != 0)) { printf("%s: timeout clock couldn't be pinned to cpu %d\n", __func__, timeout_cpu); } #ifdef SMP CPU_FOREACH(cpu) { if (cpu == timeout_cpu) continue; cc = CC_CPU(cpu); cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ callout_cpu_init(cc, cpu); snprintf(name, sizeof(name), "clock (%d)", cpu); ie = NULL; if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, INTR_MPSAFE, &cc->cc_cookie)) panic("died while creating standard software ithreads"); if (pin_pcpu_swi && (intr_event_bind(ie, cpu) != 0)) { printf("%s: per-cpu clock couldn't be pinned to " "cpu %d\n", __func__, cpu); } } #endif } SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); #define CC_HASH_SHIFT 8 static inline u_int callout_hash(sbintime_t sbt) { return (sbt >> (32 - CC_HASH_SHIFT)); } static inline u_int callout_get_bucket(sbintime_t sbt) { return (callout_hash(sbt) & callwheelmask); } void callout_process(sbintime_t now) { struct callout *tmp, *tmpn; 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); /* Compute the buckets of the last scan and present times. */ firstb = callout_hash(cc->cc_lastscan); cc->cc_lastscan = now; nowb = callout_hash(now); /* Compute the last bucket and minimum time of the bucket after it. */ if (nowb == firstb) lookahead = (SBT_1S / 16); else if (nowb - firstb == 1) lookahead = (SBT_1S / 8); else lookahead = (SBT_1S / 2); first = last = now; first += (lookahead / 2); last += lookahead; last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); lastb = callout_hash(last) - 1; max = last; /* * Check if we wrapped around the entire wheel from the last scan. * In case, we need to scan entirely the wheel for pending callouts. */ if (lastb - firstb >= callwheelsize) { lastb = firstb + callwheelsize - 1; if (nowb - firstb >= callwheelsize) nowb = lastb; } /* 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) { /* 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. */ 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; } 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; } continue; } /* Skip events from distant future. */ if (tmp->c_time >= max) goto next; /* * Event minimal time is bigger than present maximal * time, so it cannot be aggregated. */ if (tmp->c_time > last) { lastb = nowb; goto next; } /* Update first and last time, respecting this event. */ if (tmp->c_time < first) first = tmp->c_time; tmp_max = tmp->c_time + tmp->c_precision; if (tmp_max < last) last = tmp_max; next: tmp = LIST_NEXT(tmp, 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. * Stop if we looked far enough into the future. */ } while (((int)(firstb - lastb)) <= 0); cc->cc_firstevent = last; #ifndef NO_EVENTTIMERS 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; #endif mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); /* * swi_sched acquires the thread lock, so we don't want to call it * with cc_lock held; incorrect locking order. */ if (!TAILQ_EMPTY(&cc->cc_expireq)) swi_sched(cc->cc_cookie, 0); } static 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); } 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) { 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; 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 * that has been inserted, but only if really required. */ if (SBT_MAX - c->c_time < c->c_precision) c->c_precision = SBT_MAX - c->c_time; sbt = c->c_time + c->c_precision; if (sbt < cc->cc_firstevent) { cc->cc_firstevent = sbt; cpu_new_callout(cpu, sbt, c->c_time); } #endif } static 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 softclock_call_cc(struct callout *c, struct callout_cpu *cc, #ifdef CALLOUT_PROFILING int *mpcalls, int *lockcalls, int *gcalls, #endif int direct) { struct rm_priotracker tracker; void (*c_func)(void *); 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 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) sbintime_t sbt1, sbt2; struct timespec ts2; static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 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; } 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; cc_exec_curr(cc, direct) = c; cc_exec_cancel(cc, direct) = false; cc_exec_drain(cc, direct) = NULL; CC_UNLOCK(cc); if (c_lock != NULL) { class->lc_lock(c_lock, lock_status); /* * The callout may have been cancelled * while we switched locks. */ if (cc_exec_cancel(cc, direct)) { class->lc_unlock(c_lock); goto skip; } /* The callout cannot be stopped now. */ cc_exec_cancel(cc, direct) = true; if (c_lock == &Giant.lock_object) { #ifdef CALLOUT_PROFILING (*gcalls)++; #endif CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", c, c_func, c_arg); } else { #ifdef CALLOUT_PROFILING (*lockcalls)++; #endif CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", c, c_func, c_arg); } } else { #ifdef CALLOUT_PROFILING (*mpcalls)++; #endif CTR3(KTR_CALLOUT, "callout %p func %p arg %p", c, c_func, c_arg); } 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) sbt1 = sbinuptime(); #endif THREAD_NO_SLEEPING(); SDT_PROBE1(callout_execute, , , callout__start, c); c_func(c_arg); SDT_PROBE1(callout_execute, , , callout__end, c); THREAD_SLEEPING_OK(); #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) sbt2 = sbinuptime(); sbt2 -= sbt1; if (sbt2 > maxdt) { if (lastfunc != c_func || sbt2 > maxdt * 2) { ts2 = sbttots(sbt2); printf( "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); } maxdt = sbt2; lastfunc = c_func; } #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: CC_LOCK(cc); KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); cc_exec_curr(cc, direct) = NULL; if (cc_exec_drain(cc, direct)) { void (*drain)(void *); drain = cc_exec_drain(cc, direct); cc_exec_drain(cc, direct) = NULL; CC_UNLOCK(cc); drain(c_arg); CC_LOCK(cc); } 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_iflags &= ~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_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; } 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); } /* * The callout mechanism is based on the work of Adam M. Costello and * George Varghese, published in a technical report entitled "Redesigning * the BSD Callout and Timer Facilities" and modified slightly for inclusion * in FreeBSD by Justin T. Gibbs. The original work on the data structures * used in this implementation was published by G. Varghese and T. Lauck in * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for * the Efficient Implementation of a Timer Facility" in the Proceedings of * the 11th ACM Annual Symposium on Operating Systems Principles, * Austin, Texas Nov 1987. */ /* * Software (low priority) clock interrupt. * Run periodic events from timeout queue. */ void softclock(void *arg) { 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; #endif } #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; #endif CC_UNLOCK(cc); } /* * timeout -- * Execute a function after a specified length of time. * * untimeout -- * Cancel previous timeout function call. * * callout_handle_init -- * Initialize a handle so that using it with untimeout is benign. * * See AT&T BCI Driver Reference Manual for specification. This * implementation differs from that one in that although an * identification value is returned from timeout, the original * arguments to timeout as well as the identifier are used to * identify entries for untimeout. */ struct callout_handle timeout(timeout_t *ftn, void *arg, int to_ticks) { struct callout_cpu *cc; struct callout *new; struct callout_handle handle; cc = CC_CPU(timeout_cpu); CC_LOCK(cc); /* Fill in the next free callout structure. */ new = SLIST_FIRST(&cc->cc_callfree); if (new == NULL) /* 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); return (handle); } void untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) { struct callout_cpu *cc; /* * Check for a handle that was initialized * by callout_handle_init, but never used * for a real timeout. */ if (handle.callout == NULL) return; cc = callout_lock(handle.callout); if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) callout_stop(handle.callout); CC_UNLOCK(cc); } void callout_handle_init(struct callout_handle *handle) { handle->callout = NULL; } /* * New interface; clients allocate their own callout structures. * * callout_reset() - establish or change a timeout * callout_stop() - disestablish a timeout * callout_init() - initialize a callout structure so that it can * safely be passed to callout_reset() and callout_stop() * * defines three convenience macros: * * callout_active() - returns truth if callout has not been stopped, * drained, or deactivated since the last time the callout was * reset. * callout_pending() - returns truth if callout is still waiting for timeout * callout_deactivate() - marks the callout as having been serviced */ int callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, void (*ftn)(void *), void *arg, int cpu, int flags) { sbintime_t to_sbt, pr; struct callout_cpu *cc; int cancelled, direct; int ignore_cpu=0; 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; } else { if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) sbt = tick_sbt; if ((flags & C_HARDCLOCK) || #ifdef NO_EVENTTIMERS sbt >= sbt_timethreshold) { to_sbt = getsbinuptime(); /* Add safety belt for the case of hz > 1000. */ to_sbt += tc_tick_sbt - tick_sbt; #else sbt >= sbt_tickthreshold) { /* * Obtain the time of the last hardclock() call on * this CPU directly from the kern_clocksource.c. * This value is per-CPU, but it is equal for all * active ones. */ #ifdef __LP64__ to_sbt = DPCPU_GET(hardclocktime); #else spinlock_enter(); to_sbt = DPCPU_GET(hardclocktime); spinlock_exit(); #endif #endif if ((flags & C_HARDCLOCK) == 0) to_sbt += tick_sbt; } else to_sbt = sbinuptime(); if (SBT_MAX - to_sbt < sbt) to_sbt = 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; } 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); } /* * Common idioms that can be optimized in the future. */ int callout_schedule_on(struct callout *c, int to_ticks, int cpu) { return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); } int callout_schedule(struct callout *c, int to_ticks) { return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); } int _callout_stop_safe(struct callout *c, int flags, void (*drain)(void *)) { struct callout_cpu *cc, *old_cc; struct lock_class *class; int direct, sq_locked, use_lock; - int not_on_a_list; + int cancelled, not_on_a_list; if ((flags & CS_DRAIN) != 0) WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, "calling %s", __func__); /* * Some old subsystems don't hold Giant while running a callout_stop(), * so just discard this check for the moment. */ if ((flags & CS_DRAIN) == 0 && 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); 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; } /* * 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 } /* - * 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 the callout is running, try to stop it or drain it. */ - if (!(c->c_iflags & CALLOUT_PENDING)) { + if (cc_exec_curr(cc, direct) == c) { /* - * If it wasn't on the queue and it isn't the current - * callout, then we can't stop it, so just bail. - * It probably has already been run (if locking - * is properly done). You could get here if the caller - * calls stop twice in a row for example. The second - * call would fall here without CALLOUT_ACTIVE set. + * Succeed we to stop it or not, we must clear the + * active flag - this is what API users expect. */ c->c_flags &= ~CALLOUT_ACTIVE; - 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 (-1); - } if ((flags & CS_DRAIN) != 0) { /* * 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; } /* * 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) && (drain == NULL)) { /* * 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(). This *only* works with a * callout_stop() *not* callout_drain() or * callout_async_drain(). */ 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); if (drain) { cc_exec_drain(cc, direct) = drain; } CC_UNLOCK(cc); - return ((flags & CS_MIGRBLOCK) != 0); + return ((flags & CS_EXECUTING) != 0); } CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", c, c->c_func, c->c_arg); if (drain) { cc_exec_drain(cc, direct) = drain; } - CC_UNLOCK(cc); KASSERT(!sq_locked, ("sleepqueue chain still locked")); - return (0); - } + cancelled = ((flags & CS_EXECUTING) != 0); + } else + cancelled = 1; + if (sq_locked) sleepq_release(&cc_exec_waiting(cc, direct)); + if ((c->c_iflags & CALLOUT_PENDING) == 0) { + CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", + c, c->c_func, c->c_arg); + CC_UNLOCK(cc); + return (cancelled); + } + 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); } void callout_init(struct callout *c, int mpsafe) { bzero(c, sizeof *c); if (mpsafe) { c->c_lock = NULL; c->c_iflags = CALLOUT_RETURNUNLOCKED; } else { c->c_lock = &Giant.lock_object; c->c_iflags = 0; } c->c_cpu = timeout_cpu; } void _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) { bzero(c, sizeof *c); 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_cpu = timeout_cpu; } #ifdef APM_FIXUP_CALLTODO /* * Adjust the kernel calltodo timeout list. This routine is used after * an APM resume to recalculate the calltodo timer list values with the * number of hz's we have been sleeping. The next hardclock() will detect * that there are fired timers and run softclock() to execute them. * * Please note, I have not done an exhaustive analysis of what code this * might break. I am motivated to have my select()'s and alarm()'s that * have expired during suspend firing upon resume so that the applications * which set the timer can do the maintanence the timer was for as close * as possible to the originally intended time. Testing this code for a * week showed that resuming from a suspend resulted in 22 to 25 timers * firing, which seemed independent on whether the suspend was 2 hours or * 2 days. Your milage may vary. - Ken Key */ void adjust_timeout_calltodo(struct timeval *time_change) { register struct callout *p; unsigned long delta_ticks; /* * How many ticks were we asleep? * (stolen from tvtohz()). */ /* Don't do anything */ if (time_change->tv_sec < 0) return; else if (time_change->tv_sec <= LONG_MAX / 1000000) delta_ticks = howmany(time_change->tv_sec * 1000000 + time_change->tv_usec, tick) + 1; else if (time_change->tv_sec <= LONG_MAX / hz) delta_ticks = time_change->tv_sec * hz + howmany(time_change->tv_usec, tick) + 1; else delta_ticks = LONG_MAX; if (delta_ticks > INT_MAX) delta_ticks = INT_MAX; /* * Now rip through the timer calltodo list looking for timers * to expire. */ /* don't collide with softclock() */ CC_LOCK(cc); for (p = calltodo.c_next; p != NULL; p = p->c_next) { p->c_time -= delta_ticks; /* Break if the timer had more time on it than delta_ticks */ if (p->c_time > 0) break; /* take back the ticks the timer didn't use (p->c_time <= 0) */ delta_ticks = -p->c_time; } CC_UNLOCK(cc); return; } #endif /* APM_FIXUP_CALLTODO */ static int flssbt(sbintime_t sbt) { sbt += (uint64_t)sbt >> 1; if (sizeof(long) >= sizeof(sbintime_t)) return (flsl(sbt)); if (sbt >= SBT_1S) return (flsl(((uint64_t)sbt) >> 32) + 32); return (flsl(sbt)); } /* * Dump immediate statistic snapshot of the scheduled callouts. */ static int sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) { struct callout *tmp; struct callout_cpu *cc; struct callout_list *sc; sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; int ct[64], cpr[64], ccpbk[32]; int error, val, i, count, tcum, pcum, maxc, c, medc; #ifdef SMP int cpu; #endif val = 0; error = sysctl_handle_int(oidp, &val, 0, req); if (error != 0 || req->newptr == NULL) return (error); count = maxc = 0; st = spr = maxt = maxpr = 0; bzero(ccpbk, sizeof(ccpbk)); bzero(ct, sizeof(ct)); bzero(cpr, sizeof(cpr)); now = sbinuptime(); #ifdef SMP CPU_FOREACH(cpu) { cc = CC_CPU(cpu); #else cc = CC_CPU(timeout_cpu); #endif CC_LOCK(cc); for (i = 0; i < callwheelsize; i++) { sc = &cc->cc_callwheel[i]; c = 0; LIST_FOREACH(tmp, sc, c_links.le) { c++; t = tmp->c_time - now; if (t < 0) t = 0; st += t / SBT_1US; spr += tmp->c_precision / SBT_1US; if (t > maxt) maxt = t; if (tmp->c_precision > maxpr) maxpr = tmp->c_precision; ct[flssbt(t)]++; cpr[flssbt(tmp->c_precision)]++; } if (c > maxc) maxc = c; ccpbk[fls(c + c / 2)]++; count += c; } CC_UNLOCK(cc); #ifdef SMP } #endif for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) tcum += ct[i]; medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) pcum += cpr[i]; medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; for (i = 0, c = 0; i < 32 && c < count / 2; i++) c += ccpbk[i]; medc = (i >= 2) ? (1 << (i - 2)) : 0; printf("Scheduled callouts statistic snapshot:\n"); printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", medc, count / callwheelsize / mp_ncpus, (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, maxc); printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, (st / count) / 1000000, (st / count) % 1000000, maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, (spr / count) / 1000000, (spr / count) % 1000000, maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); printf(" Distribution: \tbuckets\t time\t tcum\t" " prec\t pcum\n"); for (i = 0, tcum = pcum = 0; i < 64; i++) { if (ct[i] == 0 && cpr[i] == 0) continue; t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; tcum += ct[i]; pcum += cpr[i]; printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, i - 1 - (32 - CC_HASH_SHIFT), ct[i], tcum, cpr[i], pcum); } return (error); } SYSCTL_PROC(_kern, OID_AUTO, callout_stat, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, sysctl_kern_callout_stat, "I", "Dump immediate statistic snapshot of the scheduled callouts"); #ifdef DDB static void _show_callout(struct callout *c) { db_printf("callout %p\n", c); #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); db_printf(" &c_links = %p\n", &(c->c_links)); C_DB_PRINTF("%" PRId64, c_time); C_DB_PRINTF("%" PRId64, c_precision); C_DB_PRINTF("%p", c_arg); C_DB_PRINTF("%p", c_func); C_DB_PRINTF("%p", c_lock); C_DB_PRINTF("%#x", c_flags); C_DB_PRINTF("%#x", c_iflags); C_DB_PRINTF("%d", c_cpu); #undef C_DB_PRINTF } DB_SHOW_COMMAND(callout, db_show_callout) { if (!have_addr) { db_printf("usage: show callout \n"); return; } _show_callout((struct callout *)addr); } #endif /* DDB */ Index: head/sys/kern/subr_sleepqueue.c =================================================================== --- head/sys/kern/subr_sleepqueue.c (revision 302349) +++ head/sys/kern/subr_sleepqueue.c (revision 302350) @@ -1,1377 +1,1377 @@ /*- * Copyright (c) 2004 John Baldwin * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Implementation of sleep queues used to hold queue of threads blocked on * a wait channel. Sleep queues different from turnstiles in that wait * channels are not owned by anyone, so there is no priority propagation. * Sleep queues can also provide a timeout and can also be interrupted by * signals. That said, there are several similarities between the turnstile * and sleep queue implementations. (Note: turnstiles were implemented * first.) For example, both use a hash table of the same size where each * bucket is referred to as a "chain" that contains both a spin lock and * a linked list of queues. An individual queue is located by using a hash * to pick a chain, locking the chain, and then walking the chain searching * for the queue. This means that a wait channel object does not need to * embed it's queue head just as locks do not embed their turnstile queue * head. Threads also carry around a sleep queue that they lend to the * wait channel when blocking. Just as in turnstiles, the queue includes * a free list of the sleep queues of other threads blocked on the same * wait channel in the case of multiple waiters. * * Some additional functionality provided by sleep queues include the * ability to set a timeout. The timeout is managed using a per-thread * callout that resumes a thread if it is asleep. A thread may also * catch signals while it is asleep (aka an interruptible sleep). The * signal code uses sleepq_abort() to interrupt a sleeping thread. Finally, * sleep queues also provide some extra assertions. One is not allowed to * mix the sleep/wakeup and cv APIs for a given wait channel. Also, one * must consistently use the same lock to synchronize with a wait channel, * though this check is currently only a warning for sleep/wakeup due to * pre-existing abuse of that API. The same lock must also be held when * awakening threads, though that is currently only enforced for condition * variables. */ #include __FBSDID("$FreeBSD$"); #include "opt_sleepqueue_profiling.h" #include "opt_ddb.h" #include "opt_sched.h" #include "opt_stack.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif /* * Constants for the hash table of sleep queue chains. * SC_TABLESIZE must be a power of two for SC_MASK to work properly. */ #define SC_TABLESIZE 256 /* Must be power of 2. */ #define SC_MASK (SC_TABLESIZE - 1) #define SC_SHIFT 8 #define SC_HASH(wc) ((((uintptr_t)(wc) >> SC_SHIFT) ^ (uintptr_t)(wc)) & \ SC_MASK) #define SC_LOOKUP(wc) &sleepq_chains[SC_HASH(wc)] #define NR_SLEEPQS 2 /* * There two different lists of sleep queues. Both lists are connected * via the sq_hash entries. The first list is the sleep queue chain list * that a sleep queue is on when it is attached to a wait channel. The * second list is the free list hung off of a sleep queue that is attached * to a wait channel. * * Each sleep queue also contains the wait channel it is attached to, the * list of threads blocked on that wait channel, flags specific to the * wait channel, and the lock used to synchronize with a wait channel. * The flags are used to catch mismatches between the various consumers * of the sleep queue API (e.g. sleep/wakeup and condition variables). * The lock pointer is only used when invariants are enabled for various * debugging checks. * * Locking key: * c - sleep queue chain lock */ struct sleepqueue { TAILQ_HEAD(, thread) sq_blocked[NR_SLEEPQS]; /* (c) Blocked threads. */ u_int sq_blockedcnt[NR_SLEEPQS]; /* (c) N. of blocked threads. */ LIST_ENTRY(sleepqueue) sq_hash; /* (c) Chain and free list. */ LIST_HEAD(, sleepqueue) sq_free; /* (c) Free queues. */ void *sq_wchan; /* (c) Wait channel. */ int sq_type; /* (c) Queue type. */ #ifdef INVARIANTS struct lock_object *sq_lock; /* (c) Associated lock. */ #endif }; struct sleepqueue_chain { LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */ struct mtx sc_lock; /* Spin lock for this chain. */ #ifdef SLEEPQUEUE_PROFILING u_int sc_depth; /* Length of sc_queues. */ u_int sc_max_depth; /* Max length of sc_queues. */ #endif }; #ifdef SLEEPQUEUE_PROFILING u_int sleepq_max_depth; static SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling"); static SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0, "sleepq chain stats"); SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth, 0, "maxmimum depth achieved of a single chain"); static void sleepq_profile(const char *wmesg); static int prof_enabled; #endif static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE]; static uma_zone_t sleepq_zone; /* * Prototypes for non-exported routines. */ static int sleepq_catch_signals(void *wchan, int pri); static int sleepq_check_signals(void); static int sleepq_check_timeout(void); #ifdef INVARIANTS static void sleepq_dtor(void *mem, int size, void *arg); #endif static int sleepq_init(void *mem, int size, int flags); static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri); static void sleepq_switch(void *wchan, int pri); static void sleepq_timeout(void *arg); SDT_PROBE_DECLARE(sched, , , sleep); SDT_PROBE_DECLARE(sched, , , wakeup); /* * Initialize SLEEPQUEUE_PROFILING specific sysctl nodes. * Note that it must happen after sleepinit() has been fully executed, so * it must happen after SI_SUB_KMEM SYSINIT() subsystem setup. */ #ifdef SLEEPQUEUE_PROFILING static void init_sleepqueue_profiling(void) { char chain_name[10]; struct sysctl_oid *chain_oid; u_int i; for (i = 0; i < SC_TABLESIZE; i++) { snprintf(chain_name, sizeof(chain_name), "%u", i); chain_oid = SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO, chain_name, CTLFLAG_RD, NULL, "sleepq chain stats"); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, "depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, "max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0, NULL); } } SYSINIT(sleepqueue_profiling, SI_SUB_LOCK, SI_ORDER_ANY, init_sleepqueue_profiling, NULL); #endif /* * Early initialization of sleep queues that is called from the sleepinit() * SYSINIT. */ void init_sleepqueues(void) { int i; for (i = 0; i < SC_TABLESIZE; i++) { LIST_INIT(&sleepq_chains[i].sc_queues); mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL, MTX_SPIN | MTX_RECURSE); } sleepq_zone = uma_zcreate("SLEEPQUEUE", sizeof(struct sleepqueue), #ifdef INVARIANTS NULL, sleepq_dtor, sleepq_init, NULL, UMA_ALIGN_CACHE, 0); #else NULL, NULL, sleepq_init, NULL, UMA_ALIGN_CACHE, 0); #endif thread0.td_sleepqueue = sleepq_alloc(); } /* * Get a sleep queue for a new thread. */ struct sleepqueue * sleepq_alloc(void) { return (uma_zalloc(sleepq_zone, M_WAITOK)); } /* * Free a sleep queue when a thread is destroyed. */ void sleepq_free(struct sleepqueue *sq) { uma_zfree(sleepq_zone, sq); } /* * Lock the sleep queue chain associated with the specified wait channel. */ void sleepq_lock(void *wchan) { struct sleepqueue_chain *sc; sc = SC_LOOKUP(wchan); mtx_lock_spin(&sc->sc_lock); } /* * Look up the sleep queue associated with a given wait channel in the hash * table locking the associated sleep queue chain. If no queue is found in * the table, NULL is returned. */ struct sleepqueue * sleepq_lookup(void *wchan) { struct sleepqueue_chain *sc; struct sleepqueue *sq; KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); LIST_FOREACH(sq, &sc->sc_queues, sq_hash) if (sq->sq_wchan == wchan) return (sq); return (NULL); } /* * Unlock the sleep queue chain associated with a given wait channel. */ void sleepq_release(void *wchan) { struct sleepqueue_chain *sc; sc = SC_LOOKUP(wchan); mtx_unlock_spin(&sc->sc_lock); } /* * Places the current thread on the sleep queue for the specified wait * channel. If INVARIANTS is enabled, then it associates the passed in * lock with the sleepq to make sure it is held when that sleep queue is * woken up. */ void sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg, int flags, int queue) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; td = curthread; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); MPASS(td->td_sleepqueue != NULL); MPASS(wchan != NULL); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); /* If this thread is not allowed to sleep, die a horrible death. */ KASSERT(td->td_no_sleeping == 0, ("%s: td %p to sleep on wchan %p with sleeping prohibited", __func__, td, wchan)); /* Look up the sleep queue associated with the wait channel 'wchan'. */ sq = sleepq_lookup(wchan); /* * If the wait channel does not already have a sleep queue, use * this thread's sleep queue. Otherwise, insert the current thread * into the sleep queue already in use by this wait channel. */ if (sq == NULL) { #ifdef INVARIANTS int i; sq = td->td_sleepqueue; for (i = 0; i < NR_SLEEPQS; i++) { KASSERT(TAILQ_EMPTY(&sq->sq_blocked[i]), ("thread's sleep queue %d is not empty", i)); KASSERT(sq->sq_blockedcnt[i] == 0, ("thread's sleep queue %d count mismatches", i)); } KASSERT(LIST_EMPTY(&sq->sq_free), ("thread's sleep queue has a non-empty free list")); KASSERT(sq->sq_wchan == NULL, ("stale sq_wchan pointer")); sq->sq_lock = lock; #endif #ifdef SLEEPQUEUE_PROFILING sc->sc_depth++; if (sc->sc_depth > sc->sc_max_depth) { sc->sc_max_depth = sc->sc_depth; if (sc->sc_max_depth > sleepq_max_depth) sleepq_max_depth = sc->sc_max_depth; } #endif sq = td->td_sleepqueue; LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash); sq->sq_wchan = wchan; sq->sq_type = flags & SLEEPQ_TYPE; } else { MPASS(wchan == sq->sq_wchan); MPASS(lock == sq->sq_lock); MPASS((flags & SLEEPQ_TYPE) == sq->sq_type); LIST_INSERT_HEAD(&sq->sq_free, td->td_sleepqueue, sq_hash); } thread_lock(td); TAILQ_INSERT_TAIL(&sq->sq_blocked[queue], td, td_slpq); sq->sq_blockedcnt[queue]++; td->td_sleepqueue = NULL; td->td_sqqueue = queue; td->td_wchan = wchan; td->td_wmesg = wmesg; if (flags & SLEEPQ_INTERRUPTIBLE) { td->td_flags |= TDF_SINTR; td->td_flags &= ~TDF_SLEEPABORT; } thread_unlock(td); } /* * Sets a timeout that will remove the current thread from the specified * sleep queue after timo ticks if the thread has not already been awakened. */ void 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); if (cold) panic("timed sleep before timers are working"); callout_reset_sbt_on(&td->td_slpcallout, sbt, pr, sleepq_timeout, td, PCPU_GET(cpuid), flags | C_DIRECT_EXEC); } /* * Return the number of actual sleepers for the specified queue. */ u_int sleepq_sleepcnt(void *wchan, int queue) { struct sleepqueue *sq; KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); sq = sleepq_lookup(wchan); if (sq == NULL) return (0); return (sq->sq_blockedcnt[queue]); } /* * Marks the pending sleep of the current thread as interruptible and * makes an initial check for pending signals before putting a thread * to sleep. Enters and exits with the thread lock held. Thread lock * may have transitioned from the sleepq lock to a run lock. */ static int sleepq_catch_signals(void *wchan, int pri) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; struct proc *p; struct sigacts *ps; int sig, ret; td = curthread; p = curproc; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); MPASS(wchan != NULL); if ((td->td_pflags & TDP_WAKEUP) != 0) { td->td_pflags &= ~TDP_WAKEUP; ret = EINTR; thread_lock(td); goto out; } /* * See if there are any pending signals for this thread. If not * we can switch immediately. Otherwise do the signal processing * directly. */ thread_lock(td); if ((td->td_flags & (TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK)) == 0) { sleepq_switch(wchan, pri); return (0); } thread_unlock(td); mtx_unlock_spin(&sc->sc_lock); CTR3(KTR_PROC, "sleepq catching signals: thread %p (pid %ld, %s)", (void *)td, (long)p->p_pid, td->td_name); PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); sig = cursig(td); if (sig == -1) { mtx_unlock(&ps->ps_mtx); KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY")); KASSERT(TD_SBDRY_INTR(td), ("lost TDF_SERESTART of TDF_SEINTR")); KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) != (TDF_SEINTR | TDF_SERESTART), ("both TDF_SEINTR and TDF_SERESTART")); ret = TD_SBDRY_ERRNO(td); } else if (sig == 0) { mtx_unlock(&ps->ps_mtx); ret = thread_suspend_check(1); MPASS(ret == 0 || ret == EINTR || ret == ERESTART); } else { if (SIGISMEMBER(ps->ps_sigintr, sig)) ret = EINTR; else ret = ERESTART; mtx_unlock(&ps->ps_mtx); } /* * Lock the per-process spinlock prior to dropping the PROC_LOCK * to avoid a signal delivery race. PROC_LOCK, PROC_SLOCK, and * thread_lock() are currently held in tdsendsignal(). */ PROC_SLOCK(p); mtx_lock_spin(&sc->sc_lock); PROC_UNLOCK(p); thread_lock(td); PROC_SUNLOCK(p); if (ret == 0) { sleepq_switch(wchan, pri); return (0); } out: /* * There were pending signals and this thread is still * on the sleep queue, remove it from the sleep queue. */ if (TD_ON_SLEEPQ(td)) { sq = sleepq_lookup(wchan); if (sleepq_resume_thread(sq, td, 0)) { #ifdef INVARIANTS /* * This thread hasn't gone to sleep yet, so it * should not be swapped out. */ panic("not waking up swapper"); #endif } } mtx_unlock_spin(&sc->sc_lock); MPASS(td->td_lock != &sc->sc_lock); return (ret); } /* * Switches to another thread if we are still asleep on a sleep queue. * Returns with thread lock. */ static void sleepq_switch(void *wchan, int pri) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; td = curthread; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_OWNED); /* * If we have a sleep queue, then we've already been woken up, so * just return. */ if (td->td_sleepqueue != NULL) { mtx_unlock_spin(&sc->sc_lock); return; } /* * If TDF_TIMEOUT is set, then our sleep has been timed out * already but we are still on the sleep queue, so dequeue the * thread and return. */ if (td->td_flags & TDF_TIMEOUT) { MPASS(TD_ON_SLEEPQ(td)); sq = sleepq_lookup(wchan); if (sleepq_resume_thread(sq, td, 0)) { #ifdef INVARIANTS /* * This thread hasn't gone to sleep yet, so it * should not be swapped out. */ panic("not waking up swapper"); #endif } mtx_unlock_spin(&sc->sc_lock); return; } #ifdef SLEEPQUEUE_PROFILING if (prof_enabled) sleepq_profile(td->td_wmesg); #endif MPASS(td->td_sleepqueue == NULL); sched_sleep(td, pri); thread_lock_set(td, &sc->sc_lock); SDT_PROBE0(sched, , , sleep); TD_SET_SLEEPING(td); mi_switch(SW_VOL | SWT_SLEEPQ, NULL); KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING")); CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); } /* * Check to see if we timed out. */ static int sleepq_check_timeout(void) { struct thread *td; td = curthread; THREAD_LOCK_ASSERT(td, MA_OWNED); /* * If TDF_TIMEOUT is set, we timed out. */ if (td->td_flags & TDF_TIMEOUT) { 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_safe(&td->td_slpcallout, CS_MIGRBLOCK, NULL) + else if (_callout_stop_safe(&td->td_slpcallout, CS_EXECUTING, NULL) == 0) { td->td_flags |= TDF_TIMEOUT; TD_SET_SLEEPING(td); mi_switch(SW_INVOL | SWT_SLEEPQTIMO, NULL); } return (0); } /* * Check to see if we were awoken by a signal. */ static int sleepq_check_signals(void) { struct thread *td; td = curthread; THREAD_LOCK_ASSERT(td, MA_OWNED); /* We are no longer in an interruptible sleep. */ if (td->td_flags & TDF_SINTR) td->td_flags &= ~TDF_SINTR; if (td->td_flags & TDF_SLEEPABORT) { td->td_flags &= ~TDF_SLEEPABORT; return (td->td_intrval); } return (0); } /* * Block the current thread until it is awakened from its sleep queue. */ void sleepq_wait(void *wchan, int pri) { struct thread *td; td = curthread; MPASS(!(td->td_flags & TDF_SINTR)); thread_lock(td); sleepq_switch(wchan, pri); thread_unlock(td); } /* * Block the current thread until it is awakened from its sleep queue * or it is interrupted by a signal. */ int sleepq_wait_sig(void *wchan, int pri) { int rcatch; int rval; rcatch = sleepq_catch_signals(wchan, pri); rval = sleepq_check_signals(); thread_unlock(curthread); if (rcatch) return (rcatch); return (rval); } /* * Block the current thread until it is awakened from its sleep queue * or it times out while waiting. */ int sleepq_timedwait(void *wchan, int pri) { struct thread *td; int rval; td = curthread; MPASS(!(td->td_flags & TDF_SINTR)); thread_lock(td); sleepq_switch(wchan, pri); rval = sleepq_check_timeout(); thread_unlock(td); return (rval); } /* * Block the current thread until it is awakened from its sleep queue, * it is interrupted by a signal, or it times out waiting to be awakened. */ int sleepq_timedwait_sig(void *wchan, int pri) { int rcatch, rvalt, rvals; rcatch = sleepq_catch_signals(wchan, pri); rvalt = sleepq_check_timeout(); rvals = sleepq_check_signals(); thread_unlock(curthread); if (rcatch) return (rcatch); if (rvals) return (rvals); return (rvalt); } /* * Returns the type of sleepqueue given a waitchannel. */ int sleepq_type(void *wchan) { struct sleepqueue *sq; int type; MPASS(wchan != NULL); sleepq_lock(wchan); sq = sleepq_lookup(wchan); if (sq == NULL) { sleepq_release(wchan); return (-1); } type = sq->sq_type; sleepq_release(wchan); return (type); } /* * Removes a thread from a sleep queue and makes it * runnable. */ static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri) { struct sleepqueue_chain *sc; MPASS(td != NULL); MPASS(sq->sq_wchan != NULL); MPASS(td->td_wchan == sq->sq_wchan); MPASS(td->td_sqqueue < NR_SLEEPQS && td->td_sqqueue >= 0); THREAD_LOCK_ASSERT(td, MA_OWNED); sc = SC_LOOKUP(sq->sq_wchan); mtx_assert(&sc->sc_lock, MA_OWNED); SDT_PROBE2(sched, , , wakeup, td, td->td_proc); /* Remove the thread from the queue. */ sq->sq_blockedcnt[td->td_sqqueue]--; TAILQ_REMOVE(&sq->sq_blocked[td->td_sqqueue], td, td_slpq); /* * Get a sleep queue for this thread. If this is the last waiter, * use the queue itself and take it out of the chain, otherwise, * remove a queue from the free list. */ if (LIST_EMPTY(&sq->sq_free)) { td->td_sleepqueue = sq; #ifdef INVARIANTS sq->sq_wchan = NULL; #endif #ifdef SLEEPQUEUE_PROFILING sc->sc_depth--; #endif } else td->td_sleepqueue = LIST_FIRST(&sq->sq_free); LIST_REMOVE(td->td_sleepqueue, sq_hash); td->td_wmesg = NULL; td->td_wchan = NULL; td->td_flags &= ~TDF_SINTR; CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, td->td_name); /* Adjust priority if requested. */ MPASS(pri == 0 || (pri >= PRI_MIN && pri <= PRI_MAX)); if (pri != 0 && td->td_priority > pri && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) sched_prio(td, pri); /* * Note that thread td might not be sleeping if it is running * sleepq_catch_signals() on another CPU or is blocked on its * proc lock to check signals. There's no need to mark the * thread runnable in that case. */ if (TD_IS_SLEEPING(td)) { TD_CLR_SLEEPING(td); return (setrunnable(td)); } return (0); } #ifdef INVARIANTS /* * UMA zone item deallocator. */ static void sleepq_dtor(void *mem, int size, void *arg) { struct sleepqueue *sq; int i; sq = mem; for (i = 0; i < NR_SLEEPQS; i++) { MPASS(TAILQ_EMPTY(&sq->sq_blocked[i])); MPASS(sq->sq_blockedcnt[i] == 0); } } #endif /* * UMA zone item initializer. */ static int sleepq_init(void *mem, int size, int flags) { struct sleepqueue *sq; int i; bzero(mem, size); sq = mem; for (i = 0; i < NR_SLEEPQS; i++) { TAILQ_INIT(&sq->sq_blocked[i]); sq->sq_blockedcnt[i] = 0; } LIST_INIT(&sq->sq_free); return (0); } /* * Find the highest priority thread sleeping on a wait channel and resume it. */ int sleepq_signal(void *wchan, int flags, int pri, int queue) { struct sleepqueue *sq; struct thread *td, *besttd; int wakeup_swapper; CTR2(KTR_PROC, "sleepq_signal(%p, %d)", wchan, flags); KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); sq = sleepq_lookup(wchan); if (sq == NULL) return (0); KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE), ("%s: mismatch between sleep/wakeup and cv_*", __func__)); /* * Find the highest priority thread on the queue. If there is a * tie, use the thread that first appears in the queue as it has * been sleeping the longest since threads are always added to * the tail of sleep queues. */ besttd = NULL; TAILQ_FOREACH(td, &sq->sq_blocked[queue], td_slpq) { if (besttd == NULL || td->td_priority < besttd->td_priority) besttd = td; } MPASS(besttd != NULL); thread_lock(besttd); wakeup_swapper = sleepq_resume_thread(sq, besttd, pri); thread_unlock(besttd); return (wakeup_swapper); } /* * Resume all threads sleeping on a specified wait channel. */ int sleepq_broadcast(void *wchan, int flags, int pri, int queue) { struct sleepqueue *sq; struct thread *td; int wakeup_swapper; CTR2(KTR_PROC, "sleepq_broadcast(%p, %d)", wchan, flags); KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); sq = sleepq_lookup(wchan); if (sq == NULL) return (0); KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE), ("%s: mismatch between sleep/wakeup and cv_*", __func__)); /* Resume all blocked threads on the sleep queue. */ wakeup_swapper = 0; while ((td = TAILQ_FIRST(&sq->sq_blocked[queue])) != NULL) { thread_lock(td); wakeup_swapper |= sleepq_resume_thread(sq, td, pri); thread_unlock(td); } return (wakeup_swapper); } /* * Time sleeping threads out. When the timeout expires, the thread is * removed from the sleep queue and made runnable if it is still asleep. */ static void sleepq_timeout(void *arg) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; void *wchan; int wakeup_swapper; 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; } /* * 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(). */ if (TD_ON_SLEEPQ(td)) { td->td_flags |= TDF_TIMEOUT; thread_unlock(td); return; } /* * 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; thread_unlock(td); if (wakeup_swapper) kick_proc0(); } /* * Resumes a specific thread from the sleep queue associated with a specific * wait channel if it is on that queue. */ void sleepq_remove(struct thread *td, void *wchan) { struct sleepqueue *sq; int wakeup_swapper; /* * Look up the sleep queue for this wait channel, then re-check * that the thread is asleep on that channel, if it is not, then * bail. */ MPASS(wchan != NULL); sleepq_lock(wchan); sq = sleepq_lookup(wchan); /* * We can not lock the thread here as it may be sleeping on a * different sleepq. However, holding the sleepq lock for this * wchan can guarantee that we do not miss a wakeup for this * channel. The asserts below will catch any false positives. */ if (!TD_ON_SLEEPQ(td) || td->td_wchan != wchan) { sleepq_release(wchan); return; } /* Thread is asleep on sleep queue sq, so wake it up. */ thread_lock(td); MPASS(sq != NULL); MPASS(td->td_wchan == wchan); wakeup_swapper = sleepq_resume_thread(sq, td, 0); thread_unlock(td); sleepq_release(wchan); if (wakeup_swapper) kick_proc0(); } /* * Abort a thread as if an interrupt had occurred. Only abort * interruptible waits (unfortunately it isn't safe to abort others). */ int sleepq_abort(struct thread *td, int intrval) { struct sleepqueue *sq; void *wchan; THREAD_LOCK_ASSERT(td, MA_OWNED); MPASS(TD_ON_SLEEPQ(td)); MPASS(td->td_flags & TDF_SINTR); MPASS(intrval == EINTR || intrval == ERESTART); /* * If the TDF_TIMEOUT flag is set, just leave. A * timeout is scheduled anyhow. */ if (td->td_flags & TDF_TIMEOUT) return (0); CTR3(KTR_PROC, "sleepq_abort: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); td->td_intrval = intrval; td->td_flags |= TDF_SLEEPABORT; /* * If the thread has not slept yet it will find the signal in * sleepq_catch_signals() and call sleepq_resume_thread. Otherwise * we have to do it here. */ if (!TD_IS_SLEEPING(td)) return (0); wchan = td->td_wchan; MPASS(wchan != NULL); sq = sleepq_lookup(wchan); MPASS(sq != NULL); /* Thread is asleep on sleep queue sq, so wake it up. */ return (sleepq_resume_thread(sq, td, 0)); } /* * Prints the stacks of all threads presently sleeping on wchan/queue to * the sbuf sb. Sets count_stacks_printed to the number of stacks actually * printed. Typically, this will equal the number of threads sleeping on the * queue, but may be less if sb overflowed before all stacks were printed. */ #ifdef STACK int sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue, int *count_stacks_printed) { struct thread *td, *td_next; struct sleepqueue *sq; struct stack **st; struct sbuf **td_infos; int i, stack_idx, error, stacks_to_allocate; bool finished, partial_print; error = 0; finished = false; partial_print = false; KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); stacks_to_allocate = 10; for (i = 0; i < 3 && !finished ; i++) { /* We cannot malloc while holding the queue's spinlock, so * we do our mallocs now, and hope it is enough. If it * isn't, we will free these, drop the lock, malloc more, * and try again, up to a point. After that point we will * give up and report ENOMEM. We also cannot write to sb * during this time since the client may have set the * SBUF_AUTOEXTEND flag on their sbuf, which could cause a * malloc as we print to it. So we defer actually printing * to sb until after we drop the spinlock. */ /* Where we will store the stacks. */ st = malloc(sizeof(struct stack *) * stacks_to_allocate, M_TEMP, M_WAITOK); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) st[stack_idx] = stack_create(); /* Where we will store the td name, tid, etc. */ td_infos = malloc(sizeof(struct sbuf *) * stacks_to_allocate, M_TEMP, M_WAITOK); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) td_infos[stack_idx] = sbuf_new(NULL, NULL, MAXCOMLEN + sizeof(struct thread *) * 2 + 40, SBUF_FIXEDLEN); sleepq_lock(wchan); sq = sleepq_lookup(wchan); if (sq == NULL) { /* This sleepq does not exist; exit and return ENOENT. */ error = ENOENT; finished = true; sleepq_release(wchan); goto loop_end; } stack_idx = 0; /* Save thread info */ TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq, td_next) { if (stack_idx >= stacks_to_allocate) goto loop_end; /* Note the td_lock is equal to the sleepq_lock here. */ stack_save_td(st[stack_idx], td); sbuf_printf(td_infos[stack_idx], "%d: %s %p", td->td_tid, td->td_name, td); ++stack_idx; } finished = true; sleepq_release(wchan); /* Print the stacks */ for (i = 0; i < stack_idx; i++) { sbuf_finish(td_infos[i]); sbuf_printf(sb, "--- thread %s: ---\n", sbuf_data(td_infos[i])); stack_sbuf_print(sb, st[i]); sbuf_printf(sb, "\n"); error = sbuf_error(sb); if (error == 0) *count_stacks_printed = stack_idx; } loop_end: if (!finished) sleepq_release(wchan); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) stack_destroy(st[stack_idx]); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) sbuf_delete(td_infos[stack_idx]); free(st, M_TEMP); free(td_infos, M_TEMP); stacks_to_allocate *= 10; } if (!finished && error == 0) error = ENOMEM; return (error); } #endif #ifdef SLEEPQUEUE_PROFILING #define SLEEPQ_PROF_LOCATIONS 1024 #define SLEEPQ_SBUFSIZE 512 struct sleepq_prof { LIST_ENTRY(sleepq_prof) sp_link; const char *sp_wmesg; long sp_count; }; LIST_HEAD(sqphead, sleepq_prof); struct sqphead sleepq_prof_free; struct sqphead sleepq_hash[SC_TABLESIZE]; static struct sleepq_prof sleepq_profent[SLEEPQ_PROF_LOCATIONS]; static struct mtx sleepq_prof_lock; MTX_SYSINIT(sleepq_prof_lock, &sleepq_prof_lock, "sleepq_prof", MTX_SPIN); static void sleepq_profile(const char *wmesg) { struct sleepq_prof *sp; mtx_lock_spin(&sleepq_prof_lock); if (prof_enabled == 0) goto unlock; LIST_FOREACH(sp, &sleepq_hash[SC_HASH(wmesg)], sp_link) if (sp->sp_wmesg == wmesg) goto done; sp = LIST_FIRST(&sleepq_prof_free); if (sp == NULL) goto unlock; sp->sp_wmesg = wmesg; LIST_REMOVE(sp, sp_link); LIST_INSERT_HEAD(&sleepq_hash[SC_HASH(wmesg)], sp, sp_link); done: sp->sp_count++; unlock: mtx_unlock_spin(&sleepq_prof_lock); return; } static void sleepq_prof_reset(void) { struct sleepq_prof *sp; int enabled; int i; mtx_lock_spin(&sleepq_prof_lock); enabled = prof_enabled; prof_enabled = 0; for (i = 0; i < SC_TABLESIZE; i++) LIST_INIT(&sleepq_hash[i]); LIST_INIT(&sleepq_prof_free); for (i = 0; i < SLEEPQ_PROF_LOCATIONS; i++) { sp = &sleepq_profent[i]; sp->sp_wmesg = NULL; sp->sp_count = 0; LIST_INSERT_HEAD(&sleepq_prof_free, sp, sp_link); } prof_enabled = enabled; mtx_unlock_spin(&sleepq_prof_lock); } static int enable_sleepq_prof(SYSCTL_HANDLER_ARGS) { int error, v; v = prof_enabled; error = sysctl_handle_int(oidp, &v, v, req); if (error) return (error); if (req->newptr == NULL) return (error); if (v == prof_enabled) return (0); if (v == 1) sleepq_prof_reset(); mtx_lock_spin(&sleepq_prof_lock); prof_enabled = !!v; mtx_unlock_spin(&sleepq_prof_lock); return (0); } static int reset_sleepq_prof_stats(SYSCTL_HANDLER_ARGS) { int error, v; v = 0; error = sysctl_handle_int(oidp, &v, 0, req); if (error) return (error); if (req->newptr == NULL) return (error); if (v == 0) return (0); sleepq_prof_reset(); return (0); } static int dump_sleepq_prof_stats(SYSCTL_HANDLER_ARGS) { struct sleepq_prof *sp; struct sbuf *sb; int enabled; int error; int i; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sb = sbuf_new_for_sysctl(NULL, NULL, SLEEPQ_SBUFSIZE, req); sbuf_printf(sb, "\nwmesg\tcount\n"); enabled = prof_enabled; mtx_lock_spin(&sleepq_prof_lock); prof_enabled = 0; mtx_unlock_spin(&sleepq_prof_lock); for (i = 0; i < SC_TABLESIZE; i++) { LIST_FOREACH(sp, &sleepq_hash[i], sp_link) { sbuf_printf(sb, "%s\t%ld\n", sp->sp_wmesg, sp->sp_count); } } mtx_lock_spin(&sleepq_prof_lock); prof_enabled = enabled; mtx_unlock_spin(&sleepq_prof_lock); error = sbuf_finish(sb); sbuf_delete(sb); return (error); } SYSCTL_PROC(_debug_sleepq, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, dump_sleepq_prof_stats, "A", "Sleepqueue profiling statistics"); SYSCTL_PROC(_debug_sleepq, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, NULL, 0, reset_sleepq_prof_stats, "I", "Reset sleepqueue profiling statistics"); SYSCTL_PROC(_debug_sleepq, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, NULL, 0, enable_sleepq_prof, "I", "Enable sleepqueue profiling"); #endif #ifdef DDB DB_SHOW_COMMAND(sleepq, db_show_sleepqueue) { struct sleepqueue_chain *sc; struct sleepqueue *sq; #ifdef INVARIANTS struct lock_object *lock; #endif struct thread *td; void *wchan; int i; if (!have_addr) return; /* * First, see if there is an active sleep queue for the wait channel * indicated by the address. */ wchan = (void *)addr; sc = SC_LOOKUP(wchan); LIST_FOREACH(sq, &sc->sc_queues, sq_hash) if (sq->sq_wchan == wchan) goto found; /* * Second, see if there is an active sleep queue at the address * indicated. */ for (i = 0; i < SC_TABLESIZE; i++) LIST_FOREACH(sq, &sleepq_chains[i].sc_queues, sq_hash) { if (sq == (struct sleepqueue *)addr) goto found; } db_printf("Unable to locate a sleep queue via %p\n", (void *)addr); return; found: db_printf("Wait channel: %p\n", sq->sq_wchan); db_printf("Queue type: %d\n", sq->sq_type); #ifdef INVARIANTS if (sq->sq_lock) { lock = sq->sq_lock; db_printf("Associated Interlock: %p - (%s) %s\n", lock, LOCK_CLASS(lock)->lc_name, lock->lo_name); } #endif db_printf("Blocked threads:\n"); for (i = 0; i < NR_SLEEPQS; i++) { db_printf("\nQueue[%d]:\n", i); if (TAILQ_EMPTY(&sq->sq_blocked[i])) db_printf("\tempty\n"); else TAILQ_FOREACH(td, &sq->sq_blocked[0], td_slpq) { db_printf("\t%p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); } db_printf("(expected: %u)\n", sq->sq_blockedcnt[i]); } } /* Alias 'show sleepqueue' to 'show sleepq'. */ DB_SHOW_ALIAS(sleepqueue, db_show_sleepqueue); #endif Index: head/sys/sys/callout.h =================================================================== --- head/sys/sys/callout.h (revision 302349) +++ head/sys/sys/callout.h (revision 302350) @@ -1,135 +1,134 @@ /*- * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)callout.h 8.2 (Berkeley) 1/21/94 * $FreeBSD$ */ #ifndef _SYS_CALLOUT_H_ #define _SYS_CALLOUT_H_ #include #define CALLOUT_LOCAL_ALLOC 0x0001 /* was allocated from callfree */ #define CALLOUT_ACTIVE 0x0002 /* callout is currently active */ #define CALLOUT_PENDING 0x0004 /* callout is waiting for timeout */ #define CALLOUT_MPSAFE 0x0008 /* deprecated */ #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_PROCESSED 0x0080 /* callout in wheel or processing list? */ #define CALLOUT_DIRECT 0x0100 /* allow exec from hw int context */ #define C_DIRECT_EXEC 0x0001 /* direct execution of callout */ #define C_PRELBITS 7 #define C_PRELRANGE ((1 << C_PRELBITS) - 1) #define C_PREL(x) (((x) + 1) << 1) #define C_PRELGET(x) (int)((((x) >> 1) & C_PRELRANGE) - 1) #define C_HARDCLOCK 0x0100 /* align to hardclock() calls */ #define C_ABSOLUTE 0x0200 /* event time is absolute. */ struct callout_handle { struct callout *callout; }; /* Flags for callout_stop_safe() */ #define CS_DRAIN 0x0001 /* callout_drain(), wait allowed */ -#define CS_MIGRBLOCK 0x0002 /* Block migration, return value - indicates that the callout was - executing */ +#define CS_EXECUTING 0x0002 /* Positive return value indicates that + the callout was executing */ #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, CS_DRAIN, NULL) void callout_init(struct callout *, int); void _callout_init_lock(struct callout *, struct lock_object *, int); #define callout_init_mtx(c, mtx, flags) \ _callout_init_lock((c), ((mtx) != NULL) ? &(mtx)->lock_object : \ NULL, (flags)) #define callout_init_rm(c, rm, flags) \ _callout_init_lock((c), ((rm) != NULL) ? &(rm)->lock_object : \ NULL, (flags)) #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) int callout_reset_sbt_on(struct callout *, sbintime_t, sbintime_t, void (*)(void *), 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) \ callout_reset_sbt_on((c), (sbt), (pr), (fn), (arg), PCPU_GET(cpuid),\ (flags)) #define callout_reset_on(c, to_ticks, fn, arg, cpu) \ callout_reset_sbt_on((c), tick_sbt * (to_ticks), 0, (fn), (arg), \ (cpu), C_HARDCLOCK) #define callout_reset(c, on_tick, fn, arg) \ callout_reset_on((c), (on_tick), (fn), (arg), -1) #define callout_reset_curcpu(c, on_tick, fn, arg) \ callout_reset_on((c), (on_tick), (fn), (arg), PCPU_GET(cpuid)) #define callout_schedule_sbt_on(c, sbt, pr, cpu, flags) \ callout_reset_sbt_on((c), (sbt), (pr), (c)->c_func, (c)->c_arg, \ (cpu), (flags)) #define callout_schedule_sbt(c, sbt, pr, flags) \ callout_schedule_sbt_on((c), (sbt), (pr), -1, (flags)) #define callout_schedule_sbt_curcpu(c, sbt, pr, flags) \ callout_schedule_sbt_on((c), (sbt), (pr), PCPU_GET(cpuid), (flags)) int callout_schedule(struct callout *, int); 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, NULL) int _callout_stop_safe(struct callout *, int, void (*)(void *)); void callout_process(sbintime_t now); #define callout_async_drain(c, d) \ _callout_stop_safe(c, 0, d) #endif #endif /* _SYS_CALLOUT_H_ */