Paul Jackson 053199edf5 [PATCH] cpusets: dual semaphore locking overhaul ... Overhaul cpuset locking. Replace single semaphore with two semaphores. The suggestion to use two locks was made by Roman Zippel. Both locks are global. Code that wants to modify cpusets must first acquire the exclusive manage_sem, which allows them read-only access to cpusets, and holds off other would-be modifiers. Before making actual changes, the second semaphore, callback_sem must be acquired as well. Code that needs only to query cpusets must acquire callback_sem, which is also a global exclusive lock. The earlier problems with double tripping are avoided, because it is allowed for holders of manage_sem to nest the second callback_sem lock, and only callback_sem is needed by code called from within __alloc_pages(), where the double tripping had been possible. This is not quite the same as a normal read/write semaphore, because obtaining read-only access with intent to change must hold off other such attempts, while allowing read-only access w/o such intention. Changing cpusets involves several related checks and changes, which must be done while allowing read-only queries (to avoid the double trip), but while ensuring nothing changes (holding off other would be modifiers.) This overhaul of cpuset locking also makes careful use of task_lock() to guard access to the task->cpuset pointer, closing a couple of race conditions noticed while reading this code (thanks, Roman). I've never seen these races fail in any use or test. See further the comments in the code. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2005-10-30 17:37:21 -08:00
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irq
power	[PATCH] introduce .valid callback for pm_ops	2005-10-30 17:37:15 -08:00
acct.c	[PATCH] mm: rss = file_rss + anon_rss	2005-10-29 21:40:38 -07:00
audit.c	[PATCH] gfp_t: kernel/*	2005-10-28 08:16:49 -07:00
auditsc.c	[PATCH] gfp_t: kernel/*	2005-10-28 08:16:49 -07:00
capability.c
compat.c
configs.c
cpu.c	[PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers	2005-10-30 17:37:14 -08:00
cpuset.c	[PATCH] cpusets: dual semaphore locking overhaul	2005-10-30 17:37:21 -08:00
crash_dump.c
dma.c
exec_domain.c
exit.c	[PATCH] mm: update_hiwaters just in time	2005-10-29 21:40:39 -07:00
extable.c
fork.c	[PATCH] mm: ptd_alloc take ptlock	2005-10-29 21:40:40 -07:00
futex.c	[PATCH] mm: follow_page with inner ptlock	2005-10-29 21:40:41 -07:00
intermodule.c
itimer.c
kallsyms.c
Kconfig.hz
Kconfig.preempt
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
kprobes.c
ksysfs.c
kthread.c	[PATCH] Add kthread_stop_sem()	2005-10-30 17:37:17 -08:00
Makefile	[PATCH] Remove redundant configs.o	2005-10-30 17:37:10 -08:00
module.c
panic.c
params.c	[PATCH] Ignore trailing whitespace on kernel parameters correctly	2005-09-28 07:46:41 -07:00
pid.c
posix-cpu-timers.c	[PATCH] Yet more posix-cpu-timer fixes	2005-10-27 09:08:43 -07:00
posix-timers.c	[PATCH] posix-timers: use schedule_timeout() in common_nsleep()	2005-10-30 17:37:20 -08:00
printk.c	[PATCH] Add printk_clock()	2005-09-21 10:11:54 -07:00
profile.c
ptrace.c
rcupdate.c	[PATCH] rcu: keep rcu callback event counter	2005-10-17 15:27:58 -07:00
resource.c
sched.c	[PATCH] mm: update_hiwaters just in time	2005-10-29 21:40:39 -07:00
seccomp.c
signal.c	[PATCH] Unify sys_tkill() and sys_tgkill()	2005-10-30 17:37:19 -08:00
softirq.c
softlockup.c
spinlock.c
stop_machine.c
sys_ni.c
sys.c	[PATCH] reboot: comment and factor the main reboot functions	2005-09-22 22:17:33 -07:00
sysctl.c
time.c	[PATCH] NTP shift_right cleanup	2005-10-30 17:37:18 -08:00
timer.c	[PATCH] remove timer debug field	2005-10-30 17:37:18 -08:00
uid16.c
user.c
wait.c
workqueue.c	[PATCH] Use alloc_percpu to allocate workqueues locally	2005-10-30 17:37:18 -08:00