Index: head/share/man/man4/ddb.4 =================================================================== --- head/share/man/man4/ddb.4 (revision 322852) +++ head/share/man/man4/ddb.4 (revision 322853) @@ -1,1578 +1,1579 @@ .\" .\" Mach Operating System .\" Copyright (c) 1991,1990 Carnegie Mellon University .\" Copyright (c) 2007 Robert N. M. Watson .\" All Rights Reserved. .\" .\" Permission to use, copy, modify and distribute this software and its .\" documentation is hereby granted, provided that both the copyright .\" notice and this permission notice appear in all copies of the .\" software, derivative works or modified versions, and any portions .\" thereof, and that both notices appear in supporting documentation. .\" .\" CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" .\" CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR .\" ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. .\" .\" Carnegie Mellon requests users of this software to return to .\" .\" Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU .\" School of Computer Science .\" Carnegie Mellon University .\" Pittsburgh PA 15213-3890 .\" .\" any improvements or extensions that they make and grant Carnegie Mellon .\" the rights to redistribute these changes. .\" .\" changed a \# to #, since groff choked on it. .\" .\" HISTORY .\" ddb.4,v .\" Revision 1.1 1993/07/15 18:41:02 brezak .\" Man page for DDB .\" .\" Revision 2.6 92/04/08 08:52:57 rpd .\" Changes from OSF. .\" [92/01/17 14:19:22 jsb] .\" Changes for OSF debugger modifications. .\" [91/12/12 tak] .\" .\" Revision 2.5 91/06/25 13:50:22 rpd .\" Added some watchpoint explanation. .\" [91/06/25 rpd] .\" .\" Revision 2.4 91/06/17 15:47:31 jsb .\" Added documentation for continue/c, match, search, and watchpoints. .\" I've not actually explained what a watchpoint is; maybe Rich can .\" do that (hint, hint). .\" [91/06/17 10:58:08 jsb] .\" .\" Revision 2.3 91/05/14 17:04:23 mrt .\" Correcting copyright .\" .\" Revision 2.2 91/02/14 14:10:06 mrt .\" Changed to new Mach copyright .\" [91/02/12 18:10:12 mrt] .\" .\" Revision 2.2 90/08/30 14:23:15 dbg .\" Created. .\" [90/08/30 dbg] .\" .\" $FreeBSD$ .\" -.Dd March 3, 2017 +.Dd August 24, 2017 .Dt DDB 4 .Os .Sh NAME .Nm ddb .Nd interactive kernel debugger .Sh SYNOPSIS In order to enable kernel debugging facilities include: .Bd -ragged -offset indent .Cd options KDB .Cd options DDB .Ed .Pp To prevent activation of the debugger on kernel .Xr panic 9 : .Bd -ragged -offset indent .Cd options KDB_UNATTENDED .Ed .Pp In order to print a stack trace of the current thread on the console for a panic: .Bd -ragged -offset indent .Cd options KDB_TRACE .Ed .Pp To print the numerical value of symbols in addition to the symbolic representation, define: .Bd -ragged -offset indent .Cd options DDB_NUMSYM .Ed .Pp To enable the .Xr gdb 1 backend, so that remote debugging with .Xr kgdb 1 is possible, include: .Bd -ragged -offset indent .Cd options GDB .Ed .Sh DESCRIPTION The .Nm kernel debugger is an interactive debugger with a syntax inspired by .Xr gdb 1 . If linked into the running kernel, it can be invoked locally with the .Ql debug .Xr keymap 5 action. The debugger is also invoked on kernel .Xr panic 9 if the .Va debug.debugger_on_panic .Xr sysctl 8 MIB variable is set non-zero, which is the default unless the .Dv KDB_UNATTENDED option is specified. .Pp The current location is called .Va dot . The .Va dot is displayed with a hexadecimal format at a prompt. The commands .Ic examine and .Ic write update .Va dot to the address of the last line examined or the last location modified, and set .Va next to the address of the next location to be examined or changed. Other commands do not change .Va dot , and set .Va next to be the same as .Va dot . .Pp The general command syntax is: .Ar command Ns Op Li / Ns Ar modifier .Oo Ar addr Oc Ns Op , Ns Ar count .Pp A blank line repeats the previous command from the address .Va next with count 1 and no modifiers. Specifying .Ar addr sets .Va dot to the address. Omitting .Ar addr uses .Va dot . A missing .Ar count is taken to be 1 for printing commands or infinity for stack traces. A .Ar count of -1 is equivalent to a missing .Ar count . Options that are supplied but not supported by the given .Ar command are usually ignored. .Pp The .Nm debugger has a pager feature (like the .Xr more 1 command) for the output. If an output line exceeds the number set in the .Va lines variable, it displays .Dq Li --More-- and waits for a response. The valid responses for it are: .Pp .Bl -tag -compact -width ".Li SPC" .It Li SPC one more page .It Li RET one more line .It Li q abort the current command, and return to the command input mode .El .Pp Finally, .Nm provides a small (currently 10 items) command history, and offers simple .Nm emacs Ns -style command line editing capabilities. In addition to the .Nm emacs control keys, the usual .Tn ANSI arrow keys may be used to browse through the history buffer, and move the cursor within the current line. .Sh COMMANDS .Bl -tag -width indent -compact .It Xo .Ic examine Ns Op Li / Ns Cm AISabcdghilmorsuxz ... .Oo Ar addr Oc Ns Op , Ns Ar count .Xc .It Xo .Ic x Ns Op Li / Ns Cm AISabcdghilmorsuxz ... .Oo Ar addr Oc Ns Op , Ns Ar count .Xc Display the addressed locations according to the formats in the modifier. Multiple modifier formats display multiple locations. If no format is specified, the last format specified for this command is used. .Pp The format characters are: .Bl -tag -compact -width indent .It Cm b look at by bytes (8 bits) .It Cm h look at by half words (16 bits) .It Cm l look at by long words (32 bits) .It Cm g look at by quad words (64 bits) .It Cm a print the location being displayed .It Cm A print the location with a line number if possible .It Cm x display in unsigned hex .It Cm z display in signed hex .It Cm o display in unsigned octal .It Cm d display in signed decimal .It Cm u display in unsigned decimal .It Cm r display in current radix, signed .It Cm c display low 8 bits as a character. Non-printing characters are displayed as an octal escape code (e.g., .Ql \e000 ) . .It Cm s display the null-terminated string at the location. Non-printing characters are displayed as octal escapes. .It Cm m display in unsigned hex with character dump at the end of each line. The location is also displayed in hex at the beginning of each line. .It Cm i display as an instruction .It Cm I display as an instruction with possible alternate formats depending on the machine. On i386, this selects the alternate format for the instruction decoding (16 bits in a 32-bit code segment and vice versa). .It Cm S display a symbol name for the pointer stored at the address .El .Pp .It Ic xf Examine forward: execute an .Ic examine command with the last specified parameters to it except that the next address displayed by it is used as the start address. .Pp .It Ic xb Examine backward: execute an .Ic examine command with the last specified parameters to it except that the last start address subtracted by the size displayed by it is used as the start address. .Pp .It Ic print Ns Op Li / Ns Cm acdoruxz .It Ic p Ns Op Li / Ns Cm acdoruxz Print .Ar addr Ns s according to the modifier character (as described above for .Cm examine ) . Valid formats are: .Cm a , x , z , o , d , u , r , and .Cm c . If no modifier is specified, the last one specified to it is used. The argument .Ar addr can be a string, in which case it is printed as it is. For example: .Bd -literal -offset indent print/x "eax = " $eax "\enecx = " $ecx "\en" .Ed .Pp will print like: .Bd -literal -offset indent eax = xxxxxx ecx = yyyyyy .Ed .Pp .It Xo .Ic write Ns Op Li / Ns Cm bhl .Ar addr expr1 Op Ar expr2 ... .Xc .It Xo .Ic w Ns Op Li / Ns Cm bhl .Ar addr expr1 Op Ar expr2 ... .Xc Write the expressions specified after .Ar addr on the command line at succeeding locations starting with .Ar addr . The write unit size can be specified in the modifier with a letter .Cm b (byte), .Cm h (half word) or .Cm l (long word) respectively. If omitted, long word is assumed. .Pp .Sy Warning : since there is no delimiter between expressions, strange things may happen. It is best to enclose each expression in parentheses. .Pp .It Ic set Li $ Ns Ar variable Oo Li = Oc Ar expr Set the named variable or register with the value of .Ar expr . Valid variable names are described below. .Pp .It Ic break Ns Oo Li / Ns Cm u Oc Oo Ar addr Oc Ns Op , Ns Ar count .It Ic b Ns Oo Li / Ns Cm u Oc Oo Ar addr Oc Ns Op , Ns Ar count Set a break point at .Ar addr . If .Ar count is supplied, the .Ic continue command will not stop at this break point on the first .Ar count \- 1 times that it is hit. If the break point is set, a break point number is printed with .Ql # . This number can be used in deleting the break point or adding conditions to it. .Pp If the .Cm u modifier is specified, this command sets a break point in user address space. Without the .Cm u option, the address is considered to be in the kernel space, and a wrong space address is rejected with an error message. This modifier can be used only if it is supported by machine dependent routines. .Pp .Sy Warning : If a user text is shadowed by a normal user space debugger, user space break points may not work correctly. Setting a break point at the low-level code paths may also cause strange behavior. .Pp .It Ic delete Op Ar addr .It Ic d Op Ar addr .It Ic delete Li # Ns Ar number .It Ic d Li # Ns Ar number Delete the specified break point. The break point can be specified by a break point number with .Ql # , or by using the same .Ar addr specified in the original .Ic break command, or by omitting .Ar addr to get the default address of .Va dot . .Pp .It Ic watch Oo Ar addr Oc Ns Op , Ns Ar size Set a watchpoint for a region. Execution stops when an attempt to modify the region occurs. The .Ar size argument defaults to 4. If you specify a wrong space address, the request is rejected with an error message. .Pp .Sy Warning : Attempts to watch wired kernel memory may cause unrecoverable error in some systems such as i386. Watchpoints on user addresses work best. .Pp .It Ic hwatch Oo Ar addr Oc Ns Op , Ns Ar size Set a hardware watchpoint for a region if supported by the architecture. Execution stops when an attempt to modify the region occurs. The .Ar size argument defaults to 4. .Pp .Sy Warning : The hardware debug facilities do not have a concept of separate address spaces like the watch command does. Use .Ic hwatch for setting watchpoints on kernel address locations only, and avoid its use on user mode address spaces. .Pp .It Ic dhwatch Oo Ar addr Oc Ns Op , Ns Ar size Delete specified hardware watchpoint. .Pp .It Ic step Ns Oo Li / Ns Cm p Oc Ns Op , Ns Ar count .It Ic s Ns Oo Li / Ns Cm p Oc Ns Op , Ns Ar count Single step .Ar count times. If the .Cm p modifier is specified, print each instruction at each step. Otherwise, only print the last instruction. .Pp .Sy Warning : depending on machine type, it may not be possible to single-step through some low-level code paths or user space code. On machines with software-emulated single-stepping (e.g., pmax), stepping through code executed by interrupt handlers will probably do the wrong thing. .Pp .It Ic continue Ns Op Li / Ns Cm c .It Ic c Ns Op Li / Ns Cm c Continue execution until a breakpoint or watchpoint. If the .Cm c modifier is specified, count instructions while executing. Some machines (e.g., pmax) also count loads and stores. .Pp .Sy Warning : when counting, the debugger is really silently single-stepping. This means that single-stepping on low-level code may cause strange behavior. .Pp .It Ic until Ns Op Li / Ns Cm p Stop at the next call or return instruction. If the .Cm p modifier is specified, print the call nesting depth and the cumulative instruction count at each call or return. Otherwise, only print when the matching return is hit. .Pp .It Ic next Ns Op Li / Ns Cm p .It Ic match Ns Op Li / Ns Cm p Stop at the matching return instruction. If the .Cm p modifier is specified, print the call nesting depth and the cumulative instruction count at each call or return. Otherwise, only print when the matching return is hit. .Pp .It Xo .Ic trace Ns Op Li / Ns Cm u .Op Ar pid | tid Ns .Op , Ns Ar count .Xc .It Xo .Ic t Ns Op Li / Ns Cm u .Op Ar pid | tid Ns .Op , Ns Ar count .Xc .It Xo .Ic where Ns Op Li / Ns Cm u .Op Ar pid | tid Ns .Op , Ns Ar count .Xc .It Xo .Ic bt Ns Op Li / Ns Cm u .Op Ar pid | tid Ns .Op , Ns Ar count .Xc Stack trace. The .Cm u option traces user space; if omitted, .Ic trace only traces kernel space. The optional argument .Ar count is the number of frames to be traced. If .Ar count is omitted, all frames are printed. .Pp .Sy Warning : User space stack trace is valid only if the machine dependent code supports it. .Pp .It Xo .Ic search Ns Op Li / Ns Cm bhl .Ar addr .Ar value .Op Ar mask Ns .Op , Ns Ar count .Xc Search memory for .Ar value . The optional .Ar count argument limits the search. .\" .Pp .It Xo .Ic findstack .Ar addr .Xc Prints the thread address for a thread kernel-mode stack of which contains the specified address. If the thread is not found, search the thread stack cache and prints the cached stack address. Otherwise, prints nothing. .Pp .It Ic show Cm all procs Ns Op Li / Ns Cm m .It Ic ps Ns Op Li / Ns Cm m Display all process information. The process information may not be shown if it is not supported in the machine, or the bottom of the stack of the target process is not in the main memory at that time. The .Cm m modifier will alter the display to show VM map addresses for the process and not show other information. .\" .Pp .It Ic show Cm all trace .It Ic alltrace Show a stack trace for every thread in the system. .Pp .It Ic show Cm all ttys Show all TTY's within the system. Output is similar to .Xr pstat 8 , but also includes the address of the TTY structure. .\" .Pp .It Ic show Cm all vnets Show the same output as "show vnet" does, but lists all virtualized network stacks within the system. .\" .Pp .It Ic show Cm allchains Show the same information like "show lockchain" does, but for every thread in the system. .\" .Pp .It Ic show Cm alllocks Show all locks that are currently held. This command is only available if .Xr witness 4 is included in the kernel. .\" .Pp .It Ic show Cm allpcpu The same as "show pcpu", but for every CPU present in the system. .\" .Pp .It Ic show Cm allrman Show information related with resource management, including interrupt request lines, DMA request lines, I/O ports, I/O memory addresses, and Resource IDs. .\" .Pp .It Ic show Cm apic Dump data about APIC IDT vector mappings. .\" .Pp .It Ic show Cm breaks Show breakpoints set with the "break" command. .\" .Pp .It Ic show Cm bio Ar addr Show information about the bio structure .Vt struct bio present at .Ar addr . See the .Pa sys/bio.h header file and .Xr g_bio 9 for more details on the exact meaning of the structure fields. .\" .Pp .It Ic show Cm buffer Ar addr Show information about the buf structure .Vt struct buf present at .Ar addr . See the .Pa sys/buf.h header file for more details on the exact meaning of the structure fields. .\" .Pp .It Ic show Cm callout Ar addr Show information about the callout structure .Vt struct callout present at .Ar addr . .\" .Pp .It Ic show Cm cbstat Show brief information about the TTY subsystem. .\" .Pp .It Ic show Cm cdev Without argument, show the list of all created cdev's, consisting of devfs node name and struct cdev address. When address of cdev is supplied, show some internal devfs state of the cdev. .\" .Pp .It Ic show Cm conifhk Lists hooks currently waiting for completion in run_interrupt_driven_config_hooks(). .\" .Pp .It Ic show Cm cpusets Print numbered root and assigned CPU affinity sets. See .Xr cpuset 2 for more details. .\" .Pp .It Ic show Cm cyrixreg Show registers specific to the Cyrix processor. .\" .Pp .It Ic show Cm devmap Prints the contents of the static device mapping table. Currently only available on the ARM architecture. .\" .Pp .It Ic show Cm domain Ar addr Print protocol domain structure .Vt struct domain at address .Ar addr . See the .Pa sys/domain.h header file for more details on the exact meaning of the structure fields. .\" .Pp .It Ic show Cm ffs Op Ar addr Show brief information about ffs mount at the address .Ar addr , if argument is given. Otherwise, provides the summary about each ffs mount. .\" .Pp .It Ic show Cm file Ar addr Show information about the file structure .Vt struct file present at address .Ar addr . .\" .Pp .It Ic show Cm files Show information about every file structure in the system. .\" .Pp .It Ic show Cm freepages Show the number of physical pages in each of the free lists. .\" .Pp .It Ic show Cm geom Op Ar addr If the .Ar addr argument is not given, displays the entire GEOM topology. If .Ar addr is given, displays details about the given GEOM object (class, geom, provider or consumer). .\" .Pp .It Ic show Cm idt Show IDT layout. The first column specifies the IDT vector. The second one is the name of the interrupt/trap handler. Those functions are machine dependent. .\" .Pp .It Ic show Cm igi_list Ar addr Show information about the IGMP structure .Vt struct igmp_ifsoftc present at .Ar addr . .\" .Pp .It Ic show Cm inodedeps Op Ar addr Show brief information about each inodedep structure. If .Ar addr is given, only inodedeps belonging to the fs located at the supplied address are shown. .\" .Pp .It Ic show Cm inpcb Ar addr Show information on IP Control Block .Vt struct in_pcb present at .Ar addr . .\" .Pp .It Ic show Cm intr Dump information about interrupt handlers. .\" .Pp .It Ic show Cm intrcnt Dump the interrupt statistics. .\" .Pp .It Ic show Cm irqs Show interrupt lines and their respective kernel threads. .\" .Pp .It Ic show Cm jails Show the list of .Xr jail 8 instances. In addition to what .Xr jls 8 shows, also list kernel internal details. .\" .Pp .It Ic show Cm lapic Show information from the local APIC registers for this CPU. .\" .Pp .It Ic show Cm lock Ar addr Show lock structure. The output format is as follows: .Bl -tag -width "flags" .It Ic class: Class of the lock. Possible types include .Xr mutex 9 , .Xr rmlock 9 , .Xr rwlock 9 , .Xr sx 9 . .It Ic name: Name of the lock. .It Ic flags: Flags passed to the lock initialization function. .Em flags values are lock class specific. .It Ic state: Current state of a lock. .Em state values are lock class specific. .It Ic owner: Lock owner. .El .\" .Pp .It Ic show Cm lockchain Ar addr Show all threads a particular thread at address .Ar addr -is waiting on based on non-sleepable and non-spin locks. +is waiting on based on non-spin locks. .\" .Pp .It Ic show Cm lockedbufs Show the same information as "show buf", but for every locked .Vt struct buf object. .\" .Pp .It Ic show Cm lockedvnods List all locked vnodes in the system. .\" .Pp .It Ic show Cm locks Prints all locks that are currently acquired. This command is only available if .Xr witness 4 is included in the kernel. .\" .Pp .It Ic show Cm locktree .\" .Pp .It Ic show Cm malloc Prints .Xr malloc 9 memory allocator statistics. The output format is as follows: .Pp .Bl -tag -compact -offset indent -width "Requests" .It Ic Type Specifies a type of memory. It is the same as a description string used while defining the given memory type with .Xr MALLOC_DECLARE 9 . .It Ic InUse Number of memory allocations of the given type, for which .Xr free 9 has not been called yet. .It Ic MemUse Total memory consumed by the given allocation type. .It Ic Requests Number of memory allocation requests for the given memory type. .El .Pp The same information can be gathered in userspace with .Dq Nm vmstat Fl m . .\" .Pp .It Ic show Cm map Ns Oo Li / Ns Cm f Oc Ar addr Prints the VM map at .Ar addr . If the .Cm f modifier is specified the complete map is printed. .\" .Pp .It Ic show Cm msgbuf Print the system's message buffer. It is the same output as in the .Dq Nm dmesg case. It is useful if you got a kernel panic, attached a serial cable to the machine and want to get the boot messages from before the system hang. .\" .It Ic show Cm mount Displays short info about all currently mounted file systems. .Pp .It Ic show Cm mount Ar addr Displays details about the given mount point. .\" .Pp .It Ic show Cm object Ns Oo Li / Ns Cm f Oc Ar addr Prints the VM object at .Ar addr . If the .Cm f option is specified the complete object is printed. .\" .Pp .It Ic show Cm panic Print the panic message if set. .\" .Pp .It Ic show Cm page Show statistics on VM pages. .\" .Pp .It Ic show Cm pageq Show statistics on VM page queues. .\" .Pp .It Ic show Cm pciregs Print PCI bus registers. The same information can be gathered in userspace by running .Dq Nm pciconf Fl lv . .\" .Pp .It Ic show Cm pcpu Print current processor state. The output format is as follows: .Pp .Bl -tag -compact -offset indent -width "spin locks held:" .It Ic cpuid Processor identifier. .It Ic curthread Thread pointer, process identifier and the name of the process. .It Ic curpcb Control block pointer. .It Ic fpcurthread FPU thread pointer. .It Ic idlethread Idle thread pointer. .It Ic APIC ID CPU identifier coming from APIC. .It Ic currentldt LDT pointer. .It Ic spin locks held Names of spin locks held. .El .\" .Pp .It Ic show Cm pgrpdump Dump process groups present within the system. .\" .Pp .It Ic show Cm proc Op Ar addr If no .Op Ar addr is specified, print information about the current process. Otherwise, show information about the process at address .Ar addr . .\" .Pp .It Ic show Cm procvm Show process virtual memory layout. .\" .Pp .It Ic show Cm protosw Ar addr Print protocol switch structure .Vt struct protosw at address .Ar addr . .\" .Pp .It Ic show Cm registers Ns Op Li / Ns Cm u Display the register set. If the .Cm u modifier is specified, it displays user registers instead of kernel registers or the currently saved one. .Pp .Sy Warning : The support of the .Cm u modifier depends on the machine. If not supported, incorrect information will be displayed. .\" .Pp .It Ic show Cm rman Ar addr Show resource manager object .Vt struct rman at address .Ar addr . Addresses of particular pointers can be gathered with "show allrman" command. .\" .Pp .It Ic show Cm rtc Show real time clock value. Useful for long debugging sessions. .\" .Pp .It Ic show Cm sleepchain -Show all the threads a particular thread is waiting on based on -sleepable locks. +Deprecated. +Now an alias for +.Ic show Cm lockchain . .\" .Pp .It Ic show Cm sleepq .It Ic show Cm sleepqueue Both commands provide the same functionality. They show sleepqueue .Vt struct sleepqueue structure. Sleepqueues are used within the .Fx kernel to implement sleepable synchronization primitives (thread holding a lock might sleep or be context switched), which at the time of writing are: .Xr condvar 9 , .Xr sx 9 and standard .Xr msleep 9 interface. .\" .Pp .It Ic show Cm sockbuf Ar addr .It Ic show Cm socket Ar addr Those commands print .Vt struct sockbuf and .Vt struct socket objects placed at .Ar addr . Output consists of all values present in structures mentioned. For exact interpretation and more details, visit .Pa sys/socket.h header file. .\" .Pp .It Ic show Cm sysregs Show system registers (e.g., .Li cr0-4 on i386.) Not present on some platforms. .\" .Pp .It Ic show Cm tcpcb Ar addr Print TCP control block .Vt struct tcpcb lying at address .Ar addr . For exact interpretation of output, visit .Pa netinet/tcp.h header file. .\" .Pp .It Ic show Cm thread Op Ar addr If no .Ar addr is specified, show detailed information about current thread. Otherwise, information about thread at .Ar addr is printed. .\" .Pp .It Ic show Cm threads Show all threads within the system. Output format is as follows: .Pp .Bl -tag -compact -offset indent -width "Second column" .It Ic First column Thread identifier (TID) .It Ic Second column Thread structure address .It Ic Third column Backtrace. .El .\" .Pp .It Ic show Cm tty Ar addr Display the contents of a TTY structure in a readable form. .\" .Pp .It Ic show Cm turnstile Ar addr Show turnstile .Vt struct turnstile structure at address .Ar addr . Turnstiles are structures used within the .Fx kernel to implement synchronization primitives which, while holding a specific type of lock, cannot sleep or context switch to another thread. Currently, those are: .Xr mutex 9 , .Xr rwlock 9 , .Xr rmlock 9 . .\" .Pp .It Ic show Cm uma Show UMA allocator statistics. Output consists five columns: .Pp .Bl -tag -compact -offset indent -width "Requests" .It Cm "Zone" Name of the UMA zone. The same string that was passed to .Xr uma_zcreate 9 as a first argument. .It Cm "Size" Size of a given memory object (slab). .It Cm "Used" Number of slabs being currently used. .It Cm "Free" Number of free slabs within the UMA zone. .It Cm "Requests" Number of allocations requests to the given zone. .El .Pp The very same information might be gathered in the userspace with the help of .Dq Nm vmstat Fl z . .\" .Pp .It Ic show Cm unpcb Ar addr Shows UNIX domain socket private control block .Vt struct unpcb present at the address .Ar addr . .\" .Pp .It Ic show Cm vmochk Prints, whether the internal VM objects are in a map somewhere and none have zero ref counts. .\" .Pp .It Ic show Cm vmopag This is supposed to show physical addresses consumed by a VM object. Currently, it is not possible to use this command when .Xr witness 4 is compiled in the kernel. .\" .Pp .It Ic show Cm vnet Ar addr Prints virtualized network stack .Vt struct vnet structure present at the address .Ar addr . .\" .Pp .It Ic show Cm vnode Op Ar addr Prints vnode .Vt struct vnode structure lying at .Op Ar addr . For the exact interpretation of the output, look at the .Pa sys/vnode.h header file. .\" .Pp .It Ic show Cm vnodebufs Ar addr Shows clean/dirty buffer lists of the vnode located at .Ar addr . .\" .Pp .It Ic show Cm watches Displays all watchpoints. Shows watchpoints set with "watch" command. .\" .Pp .It Ic show Cm witness Shows information about lock acquisition coming from the .Xr witness 4 subsystem. .\" .Pp .It Ic gdb Toggles between remote GDB and DDB mode. In remote GDB mode, another machine is required that runs .Xr gdb 1 using the remote debug feature, with a connection to the serial console port on the target machine. Currently only available on the i386 architecture. .Pp .It Ic halt Halt the system. .Pp .It Ic kill Ar sig pid Send signal .Ar sig to process .Ar pid . The signal is acted on upon returning from the debugger. This command can be used to kill a process causing resource contention in the case of a hung system. See .Xr signal 3 for a list of signals. Note that the arguments are reversed relative to .Xr kill 2 . .Pp .It Ic reboot Op Ar seconds .It Ic reset Op Ar seconds Hard reset the system. If the optional argument .Ar seconds is given, the debugger will wait for this long, at most a week, before rebooting. .Pp .It Ic help Print a short summary of the available commands and command abbreviations. .Pp .It Ic capture on .It Ic capture off .It Ic capture reset .It Ic capture status .Nm supports a basic output capture facility, which can be used to retrieve the results of debugging commands from userspace using .Xr sysctl 3 . .Ic capture on enables output capture; .Ic capture off disables capture. .Ic capture reset will clear the capture buffer and disable capture. .Ic capture status will report current buffer use, buffer size, and disposition of output capture. .Pp Userspace processes may inspect and manage .Nm capture state using .Xr sysctl 8 : .Pp .Dv debug.ddb.capture.bufsize may be used to query or set the current capture buffer size. .Pp .Dv debug.ddb.capture.maxbufsize may be used to query the compile-time limit on the capture buffer size. .Pp .Dv debug.ddb.capture.bytes may be used to query the number of bytes of output currently in the capture buffer. .Pp .Dv debug.ddb.capture.data returns the contents of the buffer as a string to an appropriately privileged process. .Pp This facility is particularly useful in concert with the scripting and .Xr textdump 4 facilities, allowing scripted debugging output to be captured and committed to disk as part of a textdump for later analysis. The contents of the capture buffer may also be inspected in a kernel core dump using .Xr kgdb 1 . .Pp .It Ic run .It Ic script .It Ic scripts .It Ic unscript Run, define, list, and delete scripts. See the .Sx SCRIPTING section for more information on the scripting facility. .Pp .It Ic textdump dump .It Ic textdump set .It Ic textdump status .It Ic textdump unset Use the .Ic textdump dump command to immediately perform a textdump. More information may be found in .Xr textdump 4 . The .Ic textdump set command may be used to force the next kernel core dump to be a textdump rather than a traditional memory dump or minidump. .Ic textdump status reports whether a textdump has been scheduled. .Ic textdump unset cancels a request to perform a textdump as the next kernel core dump. .El .Sh VARIABLES The debugger accesses registers and variables as .Li $ Ns Ar name . Register names are as in the .Dq Ic show Cm registers command. Some variables are suffixed with numbers, and may have some modifier following a colon immediately after the variable name. For example, register variables can have a .Cm u modifier to indicate user register (e.g., .Dq Li $eax:u ) . .Pp Built-in variables currently supported are: .Pp .Bl -tag -width ".Va tabstops" -compact .It Va radix Input and output radix. .It Va maxoff Addresses are printed as .Dq Ar symbol Ns Li + Ns Ar offset unless .Ar offset is greater than .Va maxoff . .It Va maxwidth The width of the displayed line. .It Va lines The number of lines. It is used by the built-in pager. .It Va tabstops Tab stop width. .It Va work Ns Ar xx Work variable; .Ar xx can take values from 0 to 31. .El .Sh EXPRESSIONS Most expression operators in C are supported except .Ql ~ , .Ql ^ , and unary .Ql & . Special rules in .Nm are: .Bl -tag -width ".No Identifiers" .It Identifiers The name of a symbol is translated to the value of the symbol, which is the address of the corresponding object. .Ql \&. and .Ql \&: can be used in the identifier. If supported by an object format dependent routine, .Sm off .Oo Ar filename : Oc Ar func : lineno , .Sm on .Oo Ar filename : Oc Ns Ar variable , and .Oo Ar filename : Oc Ns Ar lineno can be accepted as a symbol. .It Numbers Radix is determined by the first two letters: .Ql 0x : hex, .Ql 0o : octal, .Ql 0t : decimal; otherwise, follow current radix. .It Li \&. .Va dot .It Li + .Va next .It Li .. address of the start of the last line examined. Unlike .Va dot or .Va next , this is only changed by .Ic examine or .Ic write command. .It Li ' last address explicitly specified. .It Li $ Ns Ar variable Translated to the value of the specified variable. It may be followed by a .Ql \&: and modifiers as described above. .It Ar a Ns Li # Ns Ar b A binary operator which rounds up the left hand side to the next multiple of right hand side. .It Li * Ns Ar expr Indirection. It may be followed by a .Ql \&: and modifiers as described above. .El .Sh SCRIPTING .Nm supports a basic scripting facility to allow automating tasks or responses to specific events. Each script consists of a list of DDB commands to be executed sequentially, and is assigned a unique name. Certain script names have special meaning, and will be automatically run on various .Nm events if scripts by those names have been defined. .Pp The .Ic script command may be used to define a script by name. Scripts consist of a series of .Nm commands separated with the .Ql \&; character. For example: .Bd -literal -offset indent script kdb.enter.panic=bt; show pcpu script lockinfo=show alllocks; show lockedvnods .Ed .Pp The .Ic scripts command lists currently defined scripts. .Pp The .Ic run command execute a script by name. For example: .Bd -literal -offset indent run lockinfo .Ed .Pp The .Ic unscript command may be used to delete a script by name. For example: .Bd -literal -offset indent unscript kdb.enter.panic .Ed .Pp These functions may also be performed from userspace using the .Xr ddb 8 command. .Pp Certain scripts are run automatically, if defined, for specific .Nm events. The follow scripts are run when various events occur: .Bl -tag -width kdb.enter.powerfail .It Dv kdb.enter.acpi The kernel debugger was entered as a result of an .Xr acpi 4 event. .It Dv kdb.enter.bootflags The kernel debugger was entered at boot as a result of the debugger boot flag being set. .It Dv kdb.enter.break The kernel debugger was entered as a result of a serial or console break. .It Dv kdb.enter.cam The kernel debugger was entered as a result of a .Xr CAM 4 event. .It Dv kdb.enter.mac The kernel debugger was entered as a result of an assertion failure in the .Xr mac_test 4 module of the TrustedBSD MAC Framework. .It Dv kdb.enter.ndis The kernel debugger was entered as a result of an .Xr ndis 4 breakpoint event. .It Dv kdb.enter.netgraph The kernel debugger was entered as a result of a .Xr netgraph 4 event. .It Dv kdb.enter.panic .Xr panic 9 was called. .It Dv kdb.enter.powerfail The kernel debugger was entered as a result of a powerfail NMI on the sparc64 platform. .It Dv kdb.enter.powerpc The kernel debugger was entered as a result of an unimplemented interrupt type on the powerpc platform. .It Dv kdb.enter.sysctl The kernel debugger was entered as a result of the .Dv debug.kdb.enter sysctl being set. .It Dv kdb.enter.trapsig The kernel debugger was entered as a result of a trapsig event on the sparc64 platform. .It Dv kdb.enter.unionfs The kernel debugger was entered as a result of an assertion failure in the union file system. .It Dv kdb.enter.unknown The kernel debugger was entered, but no reason has been set. .It Dv kdb.enter.vfslock The kernel debugger was entered as a result of a VFS lock violation. .It Dv kdb.enter.watchdog The kernel debugger was entered as a result of a watchdog firing. .It Dv kdb.enter.witness The kernel debugger was entered as a result of a .Xr witness 4 violation. .El .Pp In the event that none of these scripts is found, .Nm will attempt to execute a default script: .Bl -tag -width kdb.enter.powerfail .It Dv kdb.enter.default The kernel debugger was entered, but a script exactly matching the reason for entering was not defined. This can be used as a catch-all to handle cases not specifically of interest; for example, .Dv kdb.enter.witness might be defined to have special handling, and .Dv kdb.enter.default might be defined to simply panic and reboot. .El .Sh HINTS On machines with an ISA expansion bus, a simple NMI generation card can be constructed by connecting a push button between the A01 and B01 (CHCHK# and GND) card fingers. Momentarily shorting these two fingers together may cause the bridge chipset to generate an NMI, which causes the kernel to pass control to .Nm . Some bridge chipsets do not generate a NMI on CHCHK#, so your mileage may vary. The NMI allows one to break into the debugger on a wedged machine to diagnose problems. Other bus' bridge chipsets may be able to generate NMI using bus specific methods. There are many PCI and PCIe add-in cards which can generate NMI for debugging. Modern server systems typically use IPMI to generate signals to enter the debugger. The .Dv devel/ipmitool port can be used to send the .Cd chassis power diag command which delivers an NMI to the processor. Embedded systems often use JTAG for debugging, but rarely use it in combination with .Nm . .Pp For serial consoles, you can enter the debugger by sending a BREAK condition on the serial line if .Cd options BREAK_TO_DEBUGGER is specified in the kernel. Most terminal emulation programs can send a break sequence with a special key sequence or via a menu item. However, in some setups, sending the break can be difficult to arrange or happens spuriously, so if the kernel contains .Cd options ALT_BREAK_TO_DEBUGGER then the sequence of CR TILDE CTRL-B enters the debugger; CR TILDE CTRL-P causes a panic instead of entering the debugger; and CR TILDE CTRL-R causes an immediate reboot. In all the above sequences, CR is a Carriage Return and is usually sent by hitting the Enter or Return key. TILDE is the ASCII tilde character (~). CTRL-x is Control x created by hitting the control key and then x and then releasing both. .Pp The break to enter the debugger behavior may be enabled at run-time by setting the .Xr sysctl 8 .Dv debug.kdb.break_to_debugger to 1. The alternate sequence to enter the debugger behavior may be enabled at run-time by setting the .Xr sysctl 8 .Dv debug.kdb.alt_break_to_debugger to 1. The debugger may be entered by setting the .Xr sysctl 8 .Dv debug.kdb.enter to 1. .Sh FILES Header files mentioned in this manual page can be found below .Pa /usr/include directory. .Pp .Bl -dash -compact .It .Pa sys/buf.h .It .Pa sys/domain.h .It .Pa netinet/in_pcb.h .It .Pa sys/socket.h .It .Pa sys/vnode.h .El .Sh SEE ALSO .Xr gdb 1 , .Xr kgdb 1 , .Xr acpi 4 , .Xr CAM 4 , .Xr mac_test 4 , .Xr ndis 4 , .Xr netgraph 4 , .Xr textdump 4 , .Xr witness 4 , .Xr ddb 8 , .Xr sysctl 8 , .Xr panic 9 .Sh HISTORY The .Nm debugger was developed for Mach, and ported to .Bx 386 0.1 . This manual page translated from .Xr man 7 macros by .An Garrett Wollman . .Pp .An Robert N. M. Watson added support for .Nm output capture, .Xr textdump 4 and scripting in .Fx 7.1 . Index: head/sys/kern/subr_turnstile.c =================================================================== --- head/sys/kern/subr_turnstile.c (revision 322852) +++ head/sys/kern/subr_turnstile.c (revision 322853) @@ -1,1257 +1,1254 @@ /*- * Copyright (c) 1998 Berkeley Software Design, Inc. 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. * 3. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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 BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ */ /* * Implementation of turnstiles used to hold queue of threads blocked on * non-sleepable locks. Sleepable locks use condition variables to * implement their queues. Turnstiles differ from a sleep queue in that * turnstile queue's are assigned to a lock held by an owning thread. Thus, * when one thread is enqueued onto a turnstile, it can lend its priority * to the owning thread. * * We wish to avoid bloating locks with an embedded turnstile and we do not * want to use back-pointers in the locks for the same reason. Thus, we * use a similar approach to that of Solaris 7 as described in Solaris * Internals by Jim Mauro and Richard McDougall. Turnstiles are looked up * in a hash table based on the address of the lock. Each entry in the * hash table is a linked-lists of turnstiles and is called a turnstile * chain. Each chain contains a spin mutex that protects all of the * turnstiles in the chain. * * Each time a thread is created, a turnstile is allocated from a UMA zone * and attached to that thread. When a thread blocks on a lock, if it is the * first thread to block, it lends its turnstile to the lock. If the lock * already has a turnstile, then it gives its turnstile to the lock's * turnstile's free list. When a thread is woken up, it takes a turnstile from * the free list if there are any other waiters. If it is the only thread * blocked on the lock, then it reclaims the turnstile associated with the lock * and removes it from the hash table. */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_turnstile_profiling.h" #include "opt_sched.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #include #include #endif /* * Constants for the hash table of turnstile chains. TC_SHIFT is a magic * number chosen because the sleep queue's use the same value for the * shift. Basically, we ignore the lower 8 bits of the address. * TC_TABLESIZE must be a power of two for TC_MASK to work properly. */ #define TC_TABLESIZE 128 /* Must be power of 2. */ #define TC_MASK (TC_TABLESIZE - 1) #define TC_SHIFT 8 #define TC_HASH(lock) (((uintptr_t)(lock) >> TC_SHIFT) & TC_MASK) #define TC_LOOKUP(lock) &turnstile_chains[TC_HASH(lock)] /* * There are three different lists of turnstiles as follows. The list * connected by ts_link entries is a per-thread list of all the turnstiles * attached to locks that we own. This is used to fixup our priority when * a lock is released. The other two lists use the ts_hash entries. The * first of these two is the turnstile chain list that a turnstile is on * when it is attached to a lock. The second list to use ts_hash is the * free list hung off of a turnstile that is attached to a lock. * * Each turnstile contains three lists of threads. The two ts_blocked lists * are linked list of threads blocked on the turnstile's lock. One list is * for exclusive waiters, and the other is for shared waiters. The * ts_pending list is a linked list of threads previously awakened by * turnstile_signal() or turnstile_wait() that are waiting to be put on * the run queue. * * Locking key: * c - turnstile chain lock * q - td_contested lock */ struct turnstile { struct mtx ts_lock; /* Spin lock for self. */ struct threadqueue ts_blocked[2]; /* (c + q) Blocked threads. */ struct threadqueue ts_pending; /* (c) Pending threads. */ LIST_ENTRY(turnstile) ts_hash; /* (c) Chain and free list. */ LIST_ENTRY(turnstile) ts_link; /* (q) Contested locks. */ LIST_HEAD(, turnstile) ts_free; /* (c) Free turnstiles. */ struct lock_object *ts_lockobj; /* (c) Lock we reference. */ struct thread *ts_owner; /* (c + q) Who owns the lock. */ }; struct turnstile_chain { LIST_HEAD(, turnstile) tc_turnstiles; /* List of turnstiles. */ struct mtx tc_lock; /* Spin lock for this chain. */ #ifdef TURNSTILE_PROFILING u_int tc_depth; /* Length of tc_queues. */ u_int tc_max_depth; /* Max length of tc_queues. */ #endif }; #ifdef TURNSTILE_PROFILING u_int turnstile_max_depth; static SYSCTL_NODE(_debug, OID_AUTO, turnstile, CTLFLAG_RD, 0, "turnstile profiling"); static SYSCTL_NODE(_debug_turnstile, OID_AUTO, chains, CTLFLAG_RD, 0, "turnstile chain stats"); SYSCTL_UINT(_debug_turnstile, OID_AUTO, max_depth, CTLFLAG_RD, &turnstile_max_depth, 0, "maximum depth achieved of a single chain"); #endif static struct mtx td_contested_lock; static struct turnstile_chain turnstile_chains[TC_TABLESIZE]; static uma_zone_t turnstile_zone; /* * Prototypes for non-exported routines. */ static void init_turnstile0(void *dummy); #ifdef TURNSTILE_PROFILING static void init_turnstile_profiling(void *arg); #endif -#ifdef DDB -static void print_sleepchain(struct thread *td, const char *prefix); -#endif static void propagate_priority(struct thread *td); static int turnstile_adjust_thread(struct turnstile *ts, struct thread *td); static struct thread *turnstile_first_waiter(struct turnstile *ts); static void turnstile_setowner(struct turnstile *ts, struct thread *owner); #ifdef INVARIANTS static void turnstile_dtor(void *mem, int size, void *arg); #endif static int turnstile_init(void *mem, int size, int flags); static void turnstile_fini(void *mem, int size); SDT_PROVIDER_DECLARE(sched); SDT_PROBE_DEFINE(sched, , , sleep); SDT_PROBE_DEFINE2(sched, , , wakeup, "struct thread *", "struct proc *"); /* * Walks the chain of turnstiles and their owners to propagate the priority * of the thread being blocked to all the threads holding locks that have to * release their locks before this thread can run again. */ static void propagate_priority(struct thread *td) { struct turnstile *ts; int pri; THREAD_LOCK_ASSERT(td, MA_OWNED); pri = td->td_priority; ts = td->td_blocked; THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); /* * Grab a recursive lock on this turnstile chain so it stays locked * for the whole operation. The caller expects us to return with * the original lock held. We only ever lock down the chain so * the lock order is constant. */ mtx_lock_spin(&ts->ts_lock); for (;;) { td = ts->ts_owner; if (td == NULL) { /* * This might be a read lock with no owner. There's * not much we can do, so just bail. */ mtx_unlock_spin(&ts->ts_lock); return; } thread_lock_flags(td, MTX_DUPOK); mtx_unlock_spin(&ts->ts_lock); MPASS(td->td_proc != NULL); MPASS(td->td_proc->p_magic == P_MAGIC); /* * If the thread is asleep, then we are probably about * to deadlock. To make debugging this easier, show * backtrace of misbehaving thread and panic to not * leave the kernel deadlocked. */ if (TD_IS_SLEEPING(td)) { printf( "Sleeping thread (tid %d, pid %d) owns a non-sleepable lock\n", td->td_tid, td->td_proc->p_pid); kdb_backtrace_thread(td); panic("sleeping thread"); } /* * If this thread already has higher priority than the * thread that is being blocked, we are finished. */ if (td->td_priority <= pri) { thread_unlock(td); return; } /* * Bump this thread's priority. */ sched_lend_prio(td, pri); /* * If lock holder is actually running or on the run queue * then we are done. */ if (TD_IS_RUNNING(td) || TD_ON_RUNQ(td)) { MPASS(td->td_blocked == NULL); thread_unlock(td); return; } #ifndef SMP /* * For UP, we check to see if td is curthread (this shouldn't * ever happen however as it would mean we are in a deadlock.) */ KASSERT(td != curthread, ("Deadlock detected")); #endif /* * If we aren't blocked on a lock, we should be. */ KASSERT(TD_ON_LOCK(td), ( "thread %d(%s):%d holds %s but isn't blocked on a lock\n", td->td_tid, td->td_name, td->td_state, ts->ts_lockobj->lo_name)); /* * Pick up the lock that td is blocked on. */ ts = td->td_blocked; MPASS(ts != NULL); THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); /* Resort td on the list if needed. */ if (!turnstile_adjust_thread(ts, td)) { mtx_unlock_spin(&ts->ts_lock); return; } /* The thread lock is released as ts lock above. */ } } /* * Adjust the thread's position on a turnstile after its priority has been * changed. */ static int turnstile_adjust_thread(struct turnstile *ts, struct thread *td) { struct thread *td1, *td2; int queue; THREAD_LOCK_ASSERT(td, MA_OWNED); MPASS(TD_ON_LOCK(td)); /* * This thread may not be blocked on this turnstile anymore * but instead might already be woken up on another CPU * that is waiting on the thread lock in turnstile_unpend() to * finish waking this thread up. We can detect this case * by checking to see if this thread has been given a * turnstile by either turnstile_signal() or * turnstile_broadcast(). In this case, treat the thread as * if it was already running. */ if (td->td_turnstile != NULL) return (0); /* * Check if the thread needs to be moved on the blocked chain. * It needs to be moved if either its priority is lower than * the previous thread or higher than the next thread. */ THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); td1 = TAILQ_PREV(td, threadqueue, td_lockq); td2 = TAILQ_NEXT(td, td_lockq); if ((td1 != NULL && td->td_priority < td1->td_priority) || (td2 != NULL && td->td_priority > td2->td_priority)) { /* * Remove thread from blocked chain and determine where * it should be moved to. */ queue = td->td_tsqueue; MPASS(queue == TS_EXCLUSIVE_QUEUE || queue == TS_SHARED_QUEUE); mtx_lock_spin(&td_contested_lock); TAILQ_REMOVE(&ts->ts_blocked[queue], td, td_lockq); TAILQ_FOREACH(td1, &ts->ts_blocked[queue], td_lockq) { MPASS(td1->td_proc->p_magic == P_MAGIC); if (td1->td_priority > td->td_priority) break; } if (td1 == NULL) TAILQ_INSERT_TAIL(&ts->ts_blocked[queue], td, td_lockq); else TAILQ_INSERT_BEFORE(td1, td, td_lockq); mtx_unlock_spin(&td_contested_lock); if (td1 == NULL) CTR3(KTR_LOCK, "turnstile_adjust_thread: td %d put at tail on [%p] %s", td->td_tid, ts->ts_lockobj, ts->ts_lockobj->lo_name); else CTR4(KTR_LOCK, "turnstile_adjust_thread: td %d moved before %d on [%p] %s", td->td_tid, td1->td_tid, ts->ts_lockobj, ts->ts_lockobj->lo_name); } return (1); } /* * Early initialization of turnstiles. This is not done via a SYSINIT() * since this needs to be initialized very early when mutexes are first * initialized. */ void init_turnstiles(void) { int i; for (i = 0; i < TC_TABLESIZE; i++) { LIST_INIT(&turnstile_chains[i].tc_turnstiles); mtx_init(&turnstile_chains[i].tc_lock, "turnstile chain", NULL, MTX_SPIN); } mtx_init(&td_contested_lock, "td_contested", NULL, MTX_SPIN); LIST_INIT(&thread0.td_contested); thread0.td_turnstile = NULL; } #ifdef TURNSTILE_PROFILING static void init_turnstile_profiling(void *arg) { struct sysctl_oid *chain_oid; char chain_name[10]; int i; for (i = 0; i < TC_TABLESIZE; i++) { snprintf(chain_name, sizeof(chain_name), "%d", i); chain_oid = SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_debug_turnstile_chains), OID_AUTO, chain_name, CTLFLAG_RD, NULL, "turnstile chain stats"); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, "depth", CTLFLAG_RD, &turnstile_chains[i].tc_depth, 0, NULL); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, "max_depth", CTLFLAG_RD, &turnstile_chains[i].tc_max_depth, 0, NULL); } } SYSINIT(turnstile_profiling, SI_SUB_LOCK, SI_ORDER_ANY, init_turnstile_profiling, NULL); #endif static void init_turnstile0(void *dummy) { turnstile_zone = uma_zcreate("TURNSTILE", sizeof(struct turnstile), NULL, #ifdef INVARIANTS turnstile_dtor, #else NULL, #endif turnstile_init, turnstile_fini, UMA_ALIGN_CACHE, UMA_ZONE_NOFREE); thread0.td_turnstile = turnstile_alloc(); } SYSINIT(turnstile0, SI_SUB_LOCK, SI_ORDER_ANY, init_turnstile0, NULL); /* * Update a thread on the turnstile list after it's priority has been changed. * The old priority is passed in as an argument. */ void turnstile_adjust(struct thread *td, u_char oldpri) { struct turnstile *ts; MPASS(TD_ON_LOCK(td)); /* * Pick up the lock that td is blocked on. */ ts = td->td_blocked; MPASS(ts != NULL); THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); mtx_assert(&ts->ts_lock, MA_OWNED); /* Resort the turnstile on the list. */ if (!turnstile_adjust_thread(ts, td)) return; /* * If our priority was lowered and we are at the head of the * turnstile, then propagate our new priority up the chain. * Note that we currently don't try to revoke lent priorities * when our priority goes up. */ MPASS(td->td_tsqueue == TS_EXCLUSIVE_QUEUE || td->td_tsqueue == TS_SHARED_QUEUE); if (td == TAILQ_FIRST(&ts->ts_blocked[td->td_tsqueue]) && td->td_priority < oldpri) { propagate_priority(td); } } /* * Set the owner of the lock this turnstile is attached to. */ static void turnstile_setowner(struct turnstile *ts, struct thread *owner) { mtx_assert(&td_contested_lock, MA_OWNED); MPASS(ts->ts_owner == NULL); /* A shared lock might not have an owner. */ if (owner == NULL) return; MPASS(owner->td_proc->p_magic == P_MAGIC); ts->ts_owner = owner; LIST_INSERT_HEAD(&owner->td_contested, ts, ts_link); } #ifdef INVARIANTS /* * UMA zone item deallocator. */ static void turnstile_dtor(void *mem, int size, void *arg) { struct turnstile *ts; ts = mem; MPASS(TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE])); MPASS(TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE])); MPASS(TAILQ_EMPTY(&ts->ts_pending)); } #endif /* * UMA zone item initializer. */ static int turnstile_init(void *mem, int size, int flags) { struct turnstile *ts; bzero(mem, size); ts = mem; TAILQ_INIT(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]); TAILQ_INIT(&ts->ts_blocked[TS_SHARED_QUEUE]); TAILQ_INIT(&ts->ts_pending); LIST_INIT(&ts->ts_free); mtx_init(&ts->ts_lock, "turnstile lock", NULL, MTX_SPIN | MTX_RECURSE); return (0); } static void turnstile_fini(void *mem, int size) { struct turnstile *ts; ts = mem; mtx_destroy(&ts->ts_lock); } /* * Get a turnstile for a new thread. */ struct turnstile * turnstile_alloc(void) { return (uma_zalloc(turnstile_zone, M_WAITOK)); } /* * Free a turnstile when a thread is destroyed. */ void turnstile_free(struct turnstile *ts) { uma_zfree(turnstile_zone, ts); } /* * Lock the turnstile chain associated with the specified lock. */ void turnstile_chain_lock(struct lock_object *lock) { struct turnstile_chain *tc; tc = TC_LOOKUP(lock); mtx_lock_spin(&tc->tc_lock); } struct turnstile * turnstile_trywait(struct lock_object *lock) { struct turnstile_chain *tc; struct turnstile *ts; tc = TC_LOOKUP(lock); mtx_lock_spin(&tc->tc_lock); LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash) if (ts->ts_lockobj == lock) { mtx_lock_spin(&ts->ts_lock); return (ts); } ts = curthread->td_turnstile; MPASS(ts != NULL); mtx_lock_spin(&ts->ts_lock); KASSERT(ts->ts_lockobj == NULL, ("stale ts_lockobj pointer")); ts->ts_lockobj = lock; return (ts); } void turnstile_cancel(struct turnstile *ts) { struct turnstile_chain *tc; struct lock_object *lock; mtx_assert(&ts->ts_lock, MA_OWNED); mtx_unlock_spin(&ts->ts_lock); lock = ts->ts_lockobj; if (ts == curthread->td_turnstile) ts->ts_lockobj = NULL; tc = TC_LOOKUP(lock); mtx_unlock_spin(&tc->tc_lock); } /* * Look up the turnstile for a lock in the hash table locking the associated * turnstile chain along the way. If no turnstile is found in the hash * table, NULL is returned. */ struct turnstile * turnstile_lookup(struct lock_object *lock) { struct turnstile_chain *tc; struct turnstile *ts; tc = TC_LOOKUP(lock); mtx_assert(&tc->tc_lock, MA_OWNED); LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash) if (ts->ts_lockobj == lock) { mtx_lock_spin(&ts->ts_lock); return (ts); } return (NULL); } /* * Unlock the turnstile chain associated with a given lock. */ void turnstile_chain_unlock(struct lock_object *lock) { struct turnstile_chain *tc; tc = TC_LOOKUP(lock); mtx_unlock_spin(&tc->tc_lock); } /* * Return a pointer to the thread waiting on this turnstile with the * most important priority or NULL if the turnstile has no waiters. */ static struct thread * turnstile_first_waiter(struct turnstile *ts) { struct thread *std, *xtd; std = TAILQ_FIRST(&ts->ts_blocked[TS_SHARED_QUEUE]); xtd = TAILQ_FIRST(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]); if (xtd == NULL || (std != NULL && std->td_priority < xtd->td_priority)) return (std); return (xtd); } /* * Take ownership of a turnstile and adjust the priority of the new * owner appropriately. */ void turnstile_claim(struct turnstile *ts) { struct thread *td, *owner; struct turnstile_chain *tc; mtx_assert(&ts->ts_lock, MA_OWNED); MPASS(ts != curthread->td_turnstile); owner = curthread; mtx_lock_spin(&td_contested_lock); turnstile_setowner(ts, owner); mtx_unlock_spin(&td_contested_lock); td = turnstile_first_waiter(ts); MPASS(td != NULL); MPASS(td->td_proc->p_magic == P_MAGIC); THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); /* * Update the priority of the new owner if needed. */ thread_lock(owner); if (td->td_priority < owner->td_priority) sched_lend_prio(owner, td->td_priority); thread_unlock(owner); tc = TC_LOOKUP(ts->ts_lockobj); mtx_unlock_spin(&ts->ts_lock); mtx_unlock_spin(&tc->tc_lock); } /* * Block the current thread on the turnstile assicated with 'lock'. This * function will context switch and not return until this thread has been * woken back up. This function must be called with the appropriate * turnstile chain locked and will return with it unlocked. */ void turnstile_wait(struct turnstile *ts, struct thread *owner, int queue) { struct turnstile_chain *tc; struct thread *td, *td1; struct lock_object *lock; td = curthread; mtx_assert(&ts->ts_lock, MA_OWNED); if (owner) MPASS(owner->td_proc->p_magic == P_MAGIC); MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE); /* * If the lock does not already have a turnstile, use this thread's * turnstile. Otherwise insert the current thread into the * turnstile already in use by this lock. */ tc = TC_LOOKUP(ts->ts_lockobj); mtx_assert(&tc->tc_lock, MA_OWNED); if (ts == td->td_turnstile) { #ifdef TURNSTILE_PROFILING tc->tc_depth++; if (tc->tc_depth > tc->tc_max_depth) { tc->tc_max_depth = tc->tc_depth; if (tc->tc_max_depth > turnstile_max_depth) turnstile_max_depth = tc->tc_max_depth; } #endif LIST_INSERT_HEAD(&tc->tc_turnstiles, ts, ts_hash); KASSERT(TAILQ_EMPTY(&ts->ts_pending), ("thread's turnstile has pending threads")); KASSERT(TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]), ("thread's turnstile has exclusive waiters")); KASSERT(TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]), ("thread's turnstile has shared waiters")); KASSERT(LIST_EMPTY(&ts->ts_free), ("thread's turnstile has a non-empty free list")); MPASS(ts->ts_lockobj != NULL); mtx_lock_spin(&td_contested_lock); TAILQ_INSERT_TAIL(&ts->ts_blocked[queue], td, td_lockq); turnstile_setowner(ts, owner); mtx_unlock_spin(&td_contested_lock); } else { TAILQ_FOREACH(td1, &ts->ts_blocked[queue], td_lockq) if (td1->td_priority > td->td_priority) break; mtx_lock_spin(&td_contested_lock); if (td1 != NULL) TAILQ_INSERT_BEFORE(td1, td, td_lockq); else TAILQ_INSERT_TAIL(&ts->ts_blocked[queue], td, td_lockq); MPASS(owner == ts->ts_owner); mtx_unlock_spin(&td_contested_lock); MPASS(td->td_turnstile != NULL); LIST_INSERT_HEAD(&ts->ts_free, td->td_turnstile, ts_hash); } thread_lock(td); thread_lock_set(td, &ts->ts_lock); td->td_turnstile = NULL; /* Save who we are blocked on and switch. */ lock = ts->ts_lockobj; td->td_tsqueue = queue; td->td_blocked = ts; td->td_lockname = lock->lo_name; td->td_blktick = ticks; TD_SET_LOCK(td); mtx_unlock_spin(&tc->tc_lock); propagate_priority(td); if (LOCK_LOG_TEST(lock, 0)) CTR4(KTR_LOCK, "%s: td %d blocked on [%p] %s", __func__, td->td_tid, lock, lock->lo_name); SDT_PROBE0(sched, , , sleep); THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); mi_switch(SW_VOL | SWT_TURNSTILE, NULL); if (LOCK_LOG_TEST(lock, 0)) CTR4(KTR_LOCK, "%s: td %d free from blocked on [%p] %s", __func__, td->td_tid, lock, lock->lo_name); thread_unlock(td); } /* * Pick the highest priority thread on this turnstile and put it on the * pending list. This must be called with the turnstile chain locked. */ int turnstile_signal(struct turnstile *ts, int queue) { struct turnstile_chain *tc; struct thread *td; int empty; MPASS(ts != NULL); mtx_assert(&ts->ts_lock, MA_OWNED); MPASS(curthread->td_proc->p_magic == P_MAGIC); MPASS(ts->ts_owner == curthread || ts->ts_owner == NULL); MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE); /* * Pick the highest priority thread blocked on this lock and * move it to the pending list. */ td = TAILQ_FIRST(&ts->ts_blocked[queue]); MPASS(td->td_proc->p_magic == P_MAGIC); mtx_lock_spin(&td_contested_lock); TAILQ_REMOVE(&ts->ts_blocked[queue], td, td_lockq); mtx_unlock_spin(&td_contested_lock); TAILQ_INSERT_TAIL(&ts->ts_pending, td, td_lockq); /* * If the turnstile is now empty, remove it from its chain and * give it to the about-to-be-woken thread. Otherwise take a * turnstile from the free list and give it to the thread. */ empty = TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]) && TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE]); if (empty) { tc = TC_LOOKUP(ts->ts_lockobj); mtx_assert(&tc->tc_lock, MA_OWNED); MPASS(LIST_EMPTY(&ts->ts_free)); #ifdef TURNSTILE_PROFILING tc->tc_depth--; #endif } else ts = LIST_FIRST(&ts->ts_free); MPASS(ts != NULL); LIST_REMOVE(ts, ts_hash); td->td_turnstile = ts; return (empty); } /* * Put all blocked threads on the pending list. This must be called with * the turnstile chain locked. */ void turnstile_broadcast(struct turnstile *ts, int queue) { struct turnstile_chain *tc; struct turnstile *ts1; struct thread *td; MPASS(ts != NULL); mtx_assert(&ts->ts_lock, MA_OWNED); MPASS(curthread->td_proc->p_magic == P_MAGIC); MPASS(ts->ts_owner == curthread || ts->ts_owner == NULL); /* * We must have the chain locked so that we can remove the empty * turnstile from the hash queue. */ tc = TC_LOOKUP(ts->ts_lockobj); mtx_assert(&tc->tc_lock, MA_OWNED); MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE); /* * Transfer the blocked list to the pending list. */ mtx_lock_spin(&td_contested_lock); TAILQ_CONCAT(&ts->ts_pending, &ts->ts_blocked[queue], td_lockq); mtx_unlock_spin(&td_contested_lock); /* * Give a turnstile to each thread. The last thread gets * this turnstile if the turnstile is empty. */ TAILQ_FOREACH(td, &ts->ts_pending, td_lockq) { if (LIST_EMPTY(&ts->ts_free)) { MPASS(TAILQ_NEXT(td, td_lockq) == NULL); ts1 = ts; #ifdef TURNSTILE_PROFILING tc->tc_depth--; #endif } else ts1 = LIST_FIRST(&ts->ts_free); MPASS(ts1 != NULL); LIST_REMOVE(ts1, ts_hash); td->td_turnstile = ts1; } } /* * Wakeup all threads on the pending list and adjust the priority of the * current thread appropriately. This must be called with the turnstile * chain locked. */ void turnstile_unpend(struct turnstile *ts, int owner_type) { TAILQ_HEAD( ,thread) pending_threads; struct turnstile *nts; struct thread *td; u_char cp, pri; MPASS(ts != NULL); mtx_assert(&ts->ts_lock, MA_OWNED); MPASS(ts->ts_owner == curthread || ts->ts_owner == NULL); MPASS(!TAILQ_EMPTY(&ts->ts_pending)); /* * Move the list of pending threads out of the turnstile and * into a local variable. */ TAILQ_INIT(&pending_threads); TAILQ_CONCAT(&pending_threads, &ts->ts_pending, td_lockq); #ifdef INVARIANTS if (TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]) && TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE])) ts->ts_lockobj = NULL; #endif /* * Adjust the priority of curthread based on other contested * locks it owns. Don't lower the priority below the base * priority however. */ td = curthread; pri = PRI_MAX; thread_lock(td); mtx_lock_spin(&td_contested_lock); /* * Remove the turnstile from this thread's list of contested locks * since this thread doesn't own it anymore. New threads will * not be blocking on the turnstile until it is claimed by a new * owner. There might not be a current owner if this is a shared * lock. */ if (ts->ts_owner != NULL) { ts->ts_owner = NULL; LIST_REMOVE(ts, ts_link); } LIST_FOREACH(nts, &td->td_contested, ts_link) { cp = turnstile_first_waiter(nts)->td_priority; if (cp < pri) pri = cp; } mtx_unlock_spin(&td_contested_lock); sched_unlend_prio(td, pri); thread_unlock(td); /* * Wake up all the pending threads. If a thread is not blocked * on a lock, then it is currently executing on another CPU in * turnstile_wait() or sitting on a run queue waiting to resume * in turnstile_wait(). Set a flag to force it to try to acquire * the lock again instead of blocking. */ while (!TAILQ_EMPTY(&pending_threads)) { td = TAILQ_FIRST(&pending_threads); TAILQ_REMOVE(&pending_threads, td, td_lockq); SDT_PROBE2(sched, , , wakeup, td, td->td_proc); thread_lock(td); THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock); MPASS(td->td_proc->p_magic == P_MAGIC); MPASS(TD_ON_LOCK(td)); TD_CLR_LOCK(td); MPASS(TD_CAN_RUN(td)); td->td_blocked = NULL; td->td_lockname = NULL; td->td_blktick = 0; #ifdef INVARIANTS td->td_tsqueue = 0xff; #endif sched_add(td, SRQ_BORING); thread_unlock(td); } mtx_unlock_spin(&ts->ts_lock); } /* * Give up ownership of a turnstile. This must be called with the * turnstile chain locked. */ void turnstile_disown(struct turnstile *ts) { struct thread *td; u_char cp, pri; MPASS(ts != NULL); mtx_assert(&ts->ts_lock, MA_OWNED); MPASS(ts->ts_owner == curthread); MPASS(TAILQ_EMPTY(&ts->ts_pending)); MPASS(!TAILQ_EMPTY(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE]) || !TAILQ_EMPTY(&ts->ts_blocked[TS_SHARED_QUEUE])); /* * Remove the turnstile from this thread's list of contested locks * since this thread doesn't own it anymore. New threads will * not be blocking on the turnstile until it is claimed by a new * owner. */ mtx_lock_spin(&td_contested_lock); ts->ts_owner = NULL; LIST_REMOVE(ts, ts_link); mtx_unlock_spin(&td_contested_lock); /* * Adjust the priority of curthread based on other contested * locks it owns. Don't lower the priority below the base * priority however. */ td = curthread; pri = PRI_MAX; thread_lock(td); mtx_unlock_spin(&ts->ts_lock); mtx_lock_spin(&td_contested_lock); LIST_FOREACH(ts, &td->td_contested, ts_link) { cp = turnstile_first_waiter(ts)->td_priority; if (cp < pri) pri = cp; } mtx_unlock_spin(&td_contested_lock); sched_unlend_prio(td, pri); thread_unlock(td); } /* * Return the first thread in a turnstile. */ struct thread * turnstile_head(struct turnstile *ts, int queue) { #ifdef INVARIANTS MPASS(ts != NULL); MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE); mtx_assert(&ts->ts_lock, MA_OWNED); #endif return (TAILQ_FIRST(&ts->ts_blocked[queue])); } /* * Returns true if a sub-queue of a turnstile is empty. */ int turnstile_empty(struct turnstile *ts, int queue) { #ifdef INVARIANTS MPASS(ts != NULL); MPASS(queue == TS_SHARED_QUEUE || queue == TS_EXCLUSIVE_QUEUE); mtx_assert(&ts->ts_lock, MA_OWNED); #endif return (TAILQ_EMPTY(&ts->ts_blocked[queue])); } #ifdef DDB static void print_thread(struct thread *td, const char *prefix) { db_printf("%s%p (tid %d, pid %d, \"%s\")\n", prefix, td, td->td_tid, td->td_proc->p_pid, td->td_name); } static void print_queue(struct threadqueue *queue, const char *header, const char *prefix) { struct thread *td; db_printf("%s:\n", header); if (TAILQ_EMPTY(queue)) { db_printf("%sempty\n", prefix); return; } TAILQ_FOREACH(td, queue, td_lockq) { print_thread(td, prefix); } } DB_SHOW_COMMAND(turnstile, db_show_turnstile) { struct turnstile_chain *tc; struct turnstile *ts; struct lock_object *lock; int i; if (!have_addr) return; /* * First, see if there is an active turnstile for the lock indicated * by the address. */ lock = (struct lock_object *)addr; tc = TC_LOOKUP(lock); LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash) if (ts->ts_lockobj == lock) goto found; /* * Second, see if there is an active turnstile at the address * indicated. */ for (i = 0; i < TC_TABLESIZE; i++) LIST_FOREACH(ts, &turnstile_chains[i].tc_turnstiles, ts_hash) { if (ts == (struct turnstile *)addr) goto found; } db_printf("Unable to locate a turnstile via %p\n", (void *)addr); return; found: lock = ts->ts_lockobj; db_printf("Lock: %p - (%s) %s\n", lock, LOCK_CLASS(lock)->lc_name, lock->lo_name); if (ts->ts_owner) print_thread(ts->ts_owner, "Lock Owner: "); else db_printf("Lock Owner: none\n"); print_queue(&ts->ts_blocked[TS_SHARED_QUEUE], "Shared Waiters", "\t"); print_queue(&ts->ts_blocked[TS_EXCLUSIVE_QUEUE], "Exclusive Waiters", "\t"); print_queue(&ts->ts_pending, "Pending Threads", "\t"); } /* * Show all the threads a particular thread is waiting on based on * non-spin locks. */ static void print_lockchain(struct thread *td, const char *prefix) { struct lock_object *lock; struct lock_class *class; struct turnstile *ts; struct thread *owner; /* * Follow the chain. We keep walking as long as the thread is * blocked on a lock that has an owner. */ while (!db_pager_quit) { db_printf("%sthread %d (pid %d, %s) ", prefix, td->td_tid, td->td_proc->p_pid, td->td_name); switch (td->td_state) { case TDS_INACTIVE: db_printf("is inactive\n"); return; case TDS_CAN_RUN: db_printf("can run\n"); return; case TDS_RUNQ: db_printf("is on a run queue\n"); return; case TDS_RUNNING: db_printf("running on CPU %d\n", td->td_oncpu); return; case TDS_INHIBITED: if (TD_ON_LOCK(td)) { ts = td->td_blocked; lock = ts->ts_lockobj; class = LOCK_CLASS(lock); db_printf("blocked on lock %p (%s) \"%s\"\n", lock, class->lc_name, lock->lo_name); if (ts->ts_owner == NULL) return; td = ts->ts_owner; break; } else if (TD_ON_SLEEPQ(td)) { if (!lockmgr_chain(td, &owner) && !sx_chain(td, &owner)) { db_printf("sleeping on %p \"%s\"\n", td->td_wchan, td->td_wmesg); return; } if (owner == NULL) return; td = owner; break; } db_printf("inhibited\n"); return; default: db_printf("??? (%#x)\n", td->td_state); return; } } } DB_SHOW_COMMAND(lockchain, db_show_lockchain) { struct thread *td; /* Figure out which thread to start with. */ if (have_addr) td = db_lookup_thread(addr, true); else td = kdb_thread; print_lockchain(td, ""); } DB_SHOW_ALIAS(sleepchain, db_show_lockchain); DB_SHOW_ALL_COMMAND(chains, db_show_allchains) { struct thread *td; struct proc *p; int i; i = 1; FOREACH_PROC_IN_SYSTEM(p) { FOREACH_THREAD_IN_PROC(p, td) { if ((TD_ON_LOCK(td) && LIST_EMPTY(&td->td_contested)) || (TD_IS_INHIBITED(td) && TD_ON_SLEEPQ(td))) { db_printf("chain %d:\n", i++); print_lockchain(td, " "); } if (db_pager_quit) return; } } } DB_SHOW_ALIAS(allchains, db_show_allchains) static void print_waiters(struct turnstile *ts, int indent); static void print_waiter(struct thread *td, int indent) { struct turnstile *ts; int i; if (db_pager_quit) return; for (i = 0; i < indent; i++) db_printf(" "); print_thread(td, "thread "); LIST_FOREACH(ts, &td->td_contested, ts_link) print_waiters(ts, indent + 1); } static void print_waiters(struct turnstile *ts, int indent) { struct lock_object *lock; struct lock_class *class; struct thread *td; int i; if (db_pager_quit) return; lock = ts->ts_lockobj; class = LOCK_CLASS(lock); for (i = 0; i < indent; i++) db_printf(" "); db_printf("lock %p (%s) \"%s\"\n", lock, class->lc_name, lock->lo_name); TAILQ_FOREACH(td, &ts->ts_blocked[TS_EXCLUSIVE_QUEUE], td_lockq) print_waiter(td, indent + 1); TAILQ_FOREACH(td, &ts->ts_blocked[TS_SHARED_QUEUE], td_lockq) print_waiter(td, indent + 1); TAILQ_FOREACH(td, &ts->ts_pending, td_lockq) print_waiter(td, indent + 1); } DB_SHOW_COMMAND(locktree, db_show_locktree) { struct lock_object *lock; struct lock_class *class; struct turnstile_chain *tc; struct turnstile *ts; if (!have_addr) return; lock = (struct lock_object *)addr; tc = TC_LOOKUP(lock); LIST_FOREACH(ts, &tc->tc_turnstiles, ts_hash) if (ts->ts_lockobj == lock) break; if (ts == NULL) { class = LOCK_CLASS(lock); db_printf("lock %p (%s) \"%s\"\n", lock, class->lc_name, lock->lo_name); } else print_waiters(ts, 0); } #endif