linux/kernel
Paul Jackson 6b9c2603ce [PATCH] cpuset: use rcu directly optimization
Optimize the cpuset impact on page allocation, the most performance critical
cpuset hook in the kernel.

On each page allocation, the cpuset hook needs to check for a possible change
in the current tasks cpuset.  It can now handle the common case, of no change,
without taking any spinlock or semaphore, thanks to RCU.

Convert a spinlock on the current task to an rcu_read_lock(), saving
approximately a memory barrier and an atomic op, depending on architecture.

This is done by adding rcu_assign_pointer() and synchronize_rcu() calls to the
write side of the task->cpuset pointer, in cpuset.c:attach_task(), to delay
freeing up a detached cpuset until after any critical sections referencing
that pointer.

Thanks to Andi Kleen, Nick Piggin and Eric Dumazet for ideas.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:45 -08:00
..
irq [PATCH] Alpha: convert to generic irq framework (generic part) 2006-01-06 08:33:40 -08:00
power [PATCH] swsusp: save image header first 2006-01-06 08:33:43 -08:00
.gitignore gitignore: ignore more generated files 2006-01-03 11:35:26 +01:00
acct.c [PATCH] s390: cputime_t fixes 2006-01-06 08:33:49 -08:00
audit.c [PATCH] Add try_to_freeze to kauditd 2005-12-12 08:57:43 -08:00
auditsc.c [PATCH] gfp_t: kernel/* 2005-10-28 08:16:49 -07:00
capability.c [PATCH] kernel/capability.c: add kerneldoc 2005-07-27 16:26:06 -07:00
compat.c [PATCH] kernel: fix-up schedule_timeout() usage 2005-09-10 10:06:37 -07:00
configs.c update the email address of Randy Dunlap 2006-01-03 13:37:51 +01:00
cpu.c [PATCH] clean up lock_cpu_hotplug() in cpufreq 2005-11-28 14:42:23 -08:00
cpuset.c [PATCH] cpuset: use rcu directly optimization 2006-01-08 20:13:45 -08:00
crash_dump.c [PATCH] kernel/crash_dump.c: add kerneldoc 2005-07-27 16:26:06 -07:00
dma.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exec_domain.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exit.c [PATCH] RCU signal handling 2006-01-08 20:13:40 -08:00
extable.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fork.c [PATCH] cpuset: fork hook fix 2006-01-08 20:13:43 -08:00
futex.c [PATCH] FRV: Make futex code compilable on nommu [try #2] 2006-01-06 08:33:33 -08:00
intermodule.c [PATCH] introduce and use kzalloc 2005-09-07 16:57:45 -07:00
itimer.c [PATCH] itimer fixes 2005-07-27 16:25:51 -07:00
kallsyms.c [PATCH] fix missing includes 2005-10-30 17:37:32 -08:00
Kconfig.hz [PATCH] i386: Selectable Frequency of the Timer Interrupt 2005-06-23 09:45:10 -07:00
Kconfig.preempt [PATCH] sched: voluntary kernel preemption 2005-06-25 16:24:45 -07:00
kexec.c [PATCH] mm: split page table lock 2005-10-29 21:40:42 -07:00
kfifo.c [PATCH] gfp flags annotations - part 1 2005-10-08 15:00:57 -07:00
kmod.c [PATCH] Keys: Get rid of warning in kmod.c if keys disabled 2005-10-30 17:37:23 -08:00
kprobes.c [PATCH] kprobes: increment kprobe missed count for multiprobes 2005-12-12 08:57:45 -08:00
ksysfs.c [PATCH] kobject_uevent CONFIG_NET=n fix 2006-01-04 16:18:08 -08:00
kthread.c [PATCH] Add kthread_stop_sem() 2005-10-30 17:37:17 -08:00
Makefile [PATCH] RCU torture-testing kernel module 2005-10-30 17:37:27 -08:00
module.c [PATCH] kernel/module.c: removed dead code 2006-01-06 08:33:59 -08:00
panic.c [PATCH] s390: cleanup Kconfig 2006-01-06 08:33:53 -08:00
params.c [PATCH] kernel/params.c: fix sysfs access with CONFIG_MODULES=n 2005-12-20 10:31:33 -08:00
pid.c [PATCH] RCU signal handling 2006-01-08 20:13:40 -08:00
posix-cpu-timers.c [PATCH] Fix posix-cpu-timers sched_time accumulation 2006-01-06 20:23:04 -08:00
posix-timers.c [PATCH] timespec: normalize off by one errors 2005-11-13 18:14:17 -08:00
printk.c [PATCH] Fix crash in unregister_console() 2005-11-23 16:08:39 -08:00
profile.c [PATCH] mostly_read data section 2005-07-07 18:23:46 -07:00
ptrace.c [PATCH] Fix crash when ptrace poking hugepage areas 2005-11-29 19:47:03 -08:00
rcupdate.c [PATCH] RCU signal handling 2006-01-08 20:13:40 -08:00
rcutorture.c [PATCH] Fix bug in RCU torture test 2005-12-12 08:57:42 -08:00
resource.c [PATCH] introduce and use kzalloc 2005-09-07 16:57:45 -07:00
sched.c [PATCH] RCU signal handling 2006-01-08 20:13:40 -08:00
seccomp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.c [PATCH] Simpler signal-exit concurrency handling 2006-01-08 20:13:40 -08:00
softirq.c [PATCH] cpu hoptlug: avoid usage of smp_processor_id() in preemptible code 2005-11-07 07:53:29 -08:00
softlockup.c [PATCH] quieten softlockup at boot 2005-11-09 07:55:50 -08:00
spinlock.c [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
stop_machine.c [PATCH] stop_machine() vs. synchronous IPI send deadlock 2005-11-13 18:14:16 -08:00
sys.c [PATCH] kprobes: no probes on critical path 2005-12-12 08:57:45 -08:00
sys_ni.c [PATCH] Swap Migration V5: sys_migrate_pages interface 2006-01-08 20:12:42 -08:00
sysctl.c [PATCH] Make high and batch sizes of per_cpu_pagelists configurable 2006-01-08 20:12:40 -08:00
time.c [PATCH] Add getnstimestamp function 2005-12-12 08:57:42 -08:00
timer.c [PATCH] jiffies_64 cleanup 2005-10-30 17:37:25 -08:00
uid16.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
user.c [PATCH] inotify 2005-07-12 20:38:38 -07:00
wait.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
workqueue.c [PATCH] add schedule_on_each_cpu() 2006-01-08 20:12:40 -08:00