David Xu 17ce606321 umtx operation UMTX_OP_MUTEX_WAKE has a side-effect that it accesses ... a mutex after a thread has unlocked it, it event writes data to the mutex memory to clear contention bit, there is a race that other threads can lock it and unlock it, then destroy it, so it should not write data to the mutex memory if there isn't any waiter. The new operation UMTX_OP_MUTEX_WAKE2 try to fix the problem. It requires thread library to clear the lock word entirely, then call the WAKE2 operation to check if there is any waiter in kernel, and try to wake up a thread, if necessary, the contention bit is set again by the operation. This also mitgates the chance that other threads find the contention bit and try to enter kernel to compete with each other to wake up sleeping thread, this is unnecessary. With this change, the mutex owner is no longer holding the mutex until it reaches a point where kernel umtx queue is locked, it releases the mutex as soon as possible. Performance is improved when the mutex is contensted heavily. On Intel i3-2310M, the runtime of a benchmark program is reduced from 26.87 seconds to 2.39 seconds, it even is better than UMTX_OP_MUTEX_WAKE which is deprecated now. http://people.freebsd.org/~davidxu/bench/mutex_perf.c		2012-04-05 02:24:08 +00:00
..
bus_if.m
capabilities.conf
clock_if.m
cpufreq_if.m
device_if.m
genassym.sh
imgact_aout.c
imgact_elf32.c
imgact_elf64.c
imgact_elf.c	ELF image can have several PT_NOTE program headers. Look for the ELF	2012-03-11 19:38:49 +00:00
imgact_gzip.c	Fix misuse of the kernel map in miscellaneous image activators.	2012-02-17 23:47:16 +00:00
imgact_shell.c
inflate.c
init_main.c
init_sysent.c
kern_acct.c
kern_alq.c
kern_clock.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
kern_clocksource.c	Add kern.eventtimer.activetick tunable/sysctl, specifying whether each	2012-03-13 10:21:08 +00:00
kern_condvar.c
kern_conf.c	Remove unneeded newline. It fits in 80 columns now.	2012-02-10 14:55:47 +00:00
kern_cons.c
kern_context.c
kern_cpu.c	Revert r175376 and tune cpufreq(4) frequency comparison logic instead.	2012-03-10 18:56:16 +00:00
kern_cpuset.c
kern_ctf.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
kern_descrip.c	Export some more useful info about shared memory objects to userland	2012-04-01 18:22:48 +00:00
kern_dtrace.c
kern_environment.c
kern_et.c
kern_event.c	- Add knlist_init_rw_reader() function to kqueue(9).	2012-03-26 09:34:17 +00:00
kern_exec.c	Add a new sched_clear_name() method to the scheduler interface to clear	2012-03-08 19:41:05 +00:00
kern_exit.c	When process exists, not only the children shall be reparented to	2012-04-02 19:35:36 +00:00
kern_fail.c
kern_ffclock.c
kern_fork.c	Currently, the debugger attached to the process executing vfork() does	2012-02-27 21:10:10 +00:00
kern_gzio.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
kern_hhook.c
kern_idle.c
kern_intr.c	Export intrcnt correctly when running under 32-bit compatibility.	2012-03-09 22:30:54 +00:00
kern_jail.c	Make racct and rctl correctly handle jail renaming. Previously	2012-03-06 11:05:50 +00:00
kern_khelp.c
kern_kthread.c	Add a new sched_clear_name() method to the scheduler interface to clear	2012-03-08 19:41:05 +00:00
kern_ktr.c
kern_ktrace.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
kern_linker.c	Correct debug message.	2012-03-22 09:29:07 +00:00
kern_lock.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
kern_lockf.c
kern_lockstat.c
kern_loginclass.c
kern_malloc.c	- Change contigmalloc() to use the vm_paddr_t type instead of an unsigned	2012-03-01 19:58:34 +00:00
kern_mbuf.c
kern_mib.c
kern_module.c
kern_mtxpool.c
kern_mutex.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
kern_ntptime.c
kern_osd.c
kern_physio.c
kern_pmc.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
kern_poll.c
kern_priv.c
kern_proc.c	Add a sysctl to set and retrieve binary osreldate of another process.	2012-03-23 20:05:41 +00:00
kern_prot.c
kern_racct.c	Cast wallclock.tv_sec to uint64_t to avoid overflow in the calculation.	2012-03-18 19:13:32 +00:00
kern_rctl.c
kern_resource.c
kern_rmlock.c
kern_rwlock.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
kern_sdt.c	Instead of only iterating over the set of known SDT probes when sdt.ko is	2012-03-27 15:07:43 +00:00
kern_sema.c
kern_shutdown.c	Avoid to check the same cache line/variable from all the locking	2012-01-28 14:00:21 +00:00
kern_sig.c
kern_switch.c
kern_sx.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
kern_synch.c
kern_syscalls.c
kern_sysctl.c	Handle spurious page faults that may occur in no-fault sections of the	2012-03-22 04:52:51 +00:00
kern_tc.c	o) Add COMPAT_FREEBSD32 support for MIPS kernels using the n64 ABI with userlands	2012-03-03 08:19:18 +00:00
kern_thr.c	Add a new sched_clear_name() method to the scheduler interface to clear	2012-03-08 19:41:05 +00:00
kern_thread.c
kern_time.c
kern_timeout.c
kern_umtx.c	umtx operation UMTX_OP_MUTEX_WAKE has a side-effect that it accesses	2012-04-05 02:24:08 +00:00
kern_uuid.c
kern_xxx.c
ksched.c
link_elf_obj.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
link_elf.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
linker_if.m
Make.tags.inc
Makefile
makesyscalls.sh
md4c.c
md5c.c
p1003_1b.c
posix4_mib.c
sched_4bsd.c	Add a new sched_clear_name() method to the scheduler interface to clear	2012-03-08 19:41:05 +00:00
sched_ule.c	Rewrite thread CPU usage percentage math to not depend on periodic calls	2012-03-13 08:18:54 +00:00
serdev_if.m
stack_protector.c
subr_acl_nfs4.c	Add module load/unload stubs.	2012-03-13 20:27:48 +00:00
subr_acl_posix1e.c	Add module load/unload stubs.	2012-03-13 20:27:48 +00:00
subr_autoconf.c
subr_blist.c
subr_bufring.c
subr_bus.c	Properly clear a device's devclass if DEVICE_ATTACH() fails if the device	2012-02-28 19:16:02 +00:00
subr_clock.c
subr_devstat.c
subr_disk.c
subr_eventhandler.c
subr_fattime.c
subr_firmware.c
subr_hash.c
subr_hints.c
subr_kdb.c
subr_kobj.c
subr_lock.c
subr_log.c	Add kqueue support to /dev/klog.	2012-02-01 14:34:52 +00:00
subr_mbpool.c
subr_mchain.c	- Use uint8_t for the variable x and spell the size of the variable	2012-02-06 06:03:16 +00:00
subr_module.c
subr_msgbuf.c	- Clean up timestamps in msgbuf code. The timestamps should now be	2012-03-19 00:36:32 +00:00
subr_param.c
subr_pcpu.c
subr_power.c
subr_prf.c
subr_prof.c
subr_rman.c
subr_rtc.c
subr_sbuf.c
subr_scanf.c
subr_sglist.c
subr_sleepqueue.c
subr_smp.c
subr_stack.c
subr_syscall.c	Currently, the debugger attached to the process executing vfork() does	2012-02-27 21:10:10 +00:00
subr_taskqueue.c
subr_trap.c	Add software PMC support.	2012-03-28 20:58:30 +00:00
subr_turnstile.c
subr_uio.c	Handle spurious page faults that may occur in no-fault sections of the	2012-03-22 04:52:51 +00:00
subr_unit.c
subr_witness.c
sys_capability.c	Allways call fdrop().	2012-03-12 11:56:57 +00:00
sys_generic.c	Instead of incomplete handling of read(2)/write(2) return values that	2012-03-04 14:55:37 +00:00
sys_pipe.c	Remove fifo.h. The only used function declaration from the header is	2012-03-11 12:19:58 +00:00
sys_procdesc.c
sys_process.c	Allow the parent to gather the exit status of the children reparented	2012-02-23 11:50:23 +00:00
sys_socket.c
syscalls.c
syscalls.master
systrace_args.c
sysv_ipc.c
sysv_msg.c
sysv_sem.c
sysv_shm.c	Close a race due to dropping of the map lock between creating a map entry	2012-02-19 00:28:49 +00:00
tty_compat.c
tty_info.c	Fix whitespace inconsistencies in TTY code.	2012-02-06 18:15:46 +00:00
tty_inq.c
tty_outq.c
tty_pts.c
tty_tty.c
tty_ttydisc.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
tty.c	Also call the low-level driver if ->c_iflag & (IXON|IXOFF|IXANY) changes.	2012-02-26 20:56:49 +00:00
uipc_accf.c
uipc_cow.c
uipc_debug.c
uipc_domain.c	Catch up with r195837 (2.5 years ago) which renamed net_add_domain() to domain_add().	2012-02-23 17:47:19 +00:00
uipc_mbuf2.c
uipc_mbuf.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
uipc_mqueue.c
uipc_sem.c
uipc_shm.c	Export some more useful info about shared memory objects to userland	2012-04-01 18:22:48 +00:00
uipc_sockbuf.c
uipc_socket.c	- Remove redundant call to pr_ctloutput from code that handles SO_SETFIB.	2012-04-03 18:38:00 +00:00
uipc_syscalls.c	Fix bugs which can result in a panic when an non-SCTP socket it	2012-03-15 14:13:38 +00:00
uipc_usrreq.c	Introduce VOP_UNP_BIND(), VOP_UNP_CONNECT(), and VOP_UNP_DETACH()	2012-02-29 21:38:31 +00:00
vfs_acl.c
vfs_aio.c	Add 32-bit compat code for AIO kevent flags introduced in revision 230857.	2012-02-05 04:49:31 +00:00
vfs_bio.c	This change avoids a kernel deadlock on "snaplk" when using	2012-03-01 18:45:25 +00:00
vfs_cache.c	Post r230394, the Lookup RPC counts for both NFS clients increased	2012-03-03 01:06:54 +00:00
vfs_cluster.c	Unbreak detection of the async mode for clustered writes after r231075.	2012-02-08 15:07:19 +00:00
vfs_default.c	Introduce VOP_UNP_BIND(), VOP_UNP_CONNECT(), and VOP_UNP_DETACH()	2012-02-29 21:38:31 +00:00
vfs_export.c
vfs_extattr.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
vfs_hash.c
vfs_init.c
vfs_lookup.c
vfs_mount.c	Decomission mnt_noasync. Introduce MNTK_NOASYNC mnt_kern_flag which	2012-03-09 00:12:05 +00:00
vfs_mountroot.c	Fix found places where uio_resid is truncated to int.	2012-02-21 01:05:12 +00:00
vfs_subr.c	Decomission mnt_noasync. Introduce MNTK_NOASYNC mnt_kern_flag which	2012-03-09 00:12:05 +00:00
vfs_syscalls.c	Perform the parameter validation before assigning it to a signed int	2012-03-09 21:31:12 +00:00
vfs_vnops.c	Add KTR_VFS traces to track modifications to a vnode's writecount.	2012-03-08 20:27:20 +00:00
vnode_if.src	Introduce VOP_UNP_BIND(), VOP_UNP_CONNECT(), and VOP_UNP_DETACH()	2012-02-29 21:38:31 +00:00