alistair23-linux/kernel
Frederic Weisbecker 7e3aa30ac8 cgroup: Remove task_lock() from cgroup_post_fork()
cgroup_post_fork() is protected between threadgroup_change_begin()
and threadgroup_change_end() against concurrent changes of the
child's css_set in cgroup_task_migrate(). Also the child can't
exit and call cgroup_exit() at this stage, this means it's css_set
can't be changed with init_css_set concurrently.

For these reasons, we don't need to hold task_lock() on the child
because it's css_set can only remain stable in this place.

Let's remove the lock there.

v2: Update comment to explain that we are safe against
cgroup_exit()

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Containers <containers@lists.linux-foundation.org>
Cc: Cgroups <cgroups@vger.kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Menage <paul@paulmenage.org>
Cc: Mandeep Singh Baines <msb@chromium.org>
2011-12-27 09:05:20 -08:00
..
debug Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
events cgroup: don't use subsys->can_attach_task() or ->attach_task() 2011-12-12 18:12:21 -08:00
gcov
irq Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-11-17 11:46:26 -02:00
power Merge branch 'pm-freezer' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into pm-freezer 2011-11-23 21:09:02 +01:00
time kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure 2011-10-31 19:30:05 -04:00
trace kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure 2011-10-31 19:30:05 -04:00
.gitignore
acct.c
async.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
audit.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
audit.h
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
backtracetest.c
bounds.c
capability.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
cgroup.c cgroup: Remove task_lock() from cgroup_post_fork() 2011-12-27 09:05:20 -08:00
cgroup_freezer.c cgroup: don't use subsys->can_attach_task() or ->attach_task() 2011-12-12 18:12:21 -08:00
compat.c kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure 2011-10-31 19:30:05 -04:00
configs.c
cpu.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
cpu_pm.c cpu_pm: call notifiers during suspend 2011-09-23 12:05:29 +05:30
cpuset.c cgroup, cpuset: don't use ss->pre_attach() 2011-12-12 18:12:22 -08:00
crash_dump.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
cred.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
delayacct.c
dma.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
elfcore.c
exec_domain.c
exit.c freezer: remove racy clear_freeze_flag() and set PF_NOFREEZE on dead tasks 2011-11-21 12:32:23 -08:00
extable.c
fork.c threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem 2011-12-12 18:12:21 -08:00
freezer.c freezer: kill unused set_freezable_with_signal() 2011-11-23 09:28:17 -08:00
futex.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
futex_compat.c
groups.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
hrtimer.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
hung_task.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
irq_work.c kernel: fix two implicit header assumptions in irq_work.c 2011-10-31 09:20:12 -04:00
itimer.c
jump_label.c jump-label: initialize jump-label subsystem much earlier 2011-10-25 11:55:15 -07:00
kallsyms.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c [S390] kdump: Add infrastructure for unmapping crashkernel memory 2011-10-30 15:16:42 +01:00
kfifo.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
kmod.c kmod: prevent kmod_loop_msg overflow in __request_module() 2011-10-26 13:10:39 +10:30
kprobes.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
ksysfs.c kernel: ksysfs.c is implicitly using stat.h 2011-10-31 09:20:13 -04:00
kthread.c freezer: kill unused set_freezable_with_signal() 2011-11-23 09:28:17 -08:00
latencytop.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
lockdep.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 16:26:53 +02:00
lockdep_internals.h
lockdep_proc.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
lockdep_states.h
Makefile Merge branch 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm 2011-10-28 12:02:27 -07:00
module.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
mutex-debug.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
mutex-debug.h
mutex.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
mutex.h
notifier.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
nsproxy.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
padata.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
panic.c module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree 2011-11-07 07:54:42 +10:30
params.c kernel: params.c needs module.h not moduleparam.h 2011-10-31 09:20:13 -04:00
pid.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
pid_namespace.c
posix-cpu-timers.c Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 16:17:32 +02:00
posix-timers.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
printk.c printk: remove bounds checking for log_prefix 2011-10-31 17:30:53 -07:00
profile.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
ptrace.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
range.c range: fix bogus misuse of module.h to get printk() 2011-10-31 09:20:11 -04:00
rcu.h rcu: Add grace-period, quiescent-state, and call_rcu trace events 2011-09-28 21:38:21 -07:00
rcupdate.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rcutiny.c kernel: fix up module header handling in rcutiny files 2011-10-31 09:20:13 -04:00
rcutiny_plugin.h kernel: fix up module header handling in rcutiny files 2011-10-31 09:20:13 -04:00
rcutorture.c rcu: Make rcu_torture_boost() exit loops at end of test 2011-09-28 21:38:46 -07:00
rcutree.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rcutree.h rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states 2011-09-28 21:38:48 -07:00
rcutree_plugin.h rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states 2011-09-28 21:38:48 -07:00
rcutree_trace.c rcu: Simplify quiescent-state accounting 2011-09-28 21:38:22 -07:00
relay.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
res_counter.c resource cgroups: remove bogus cast 2011-12-13 07:43:08 -08:00
resource.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rtmutex-debug.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rtmutex-debug.h
rtmutex-tester.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rtmutex.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
rtmutex.h
rtmutex_common.h
rwsem.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
sched.c cgroup: don't use subsys->can_attach_task() or ->attach_task() 2011-12-12 18:12:21 -08:00
sched_autogroup.c
sched_autogroup.h
sched_clock.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
sched_cpupri.c
sched_cpupri.h
sched_debug.c
sched_fair.c sched: Wrap scheduler p->cpus_allowed access 2011-10-06 12:46:56 +02:00
sched_features.h
sched_idletask.c
sched_rt.c sched: Warn on rt throttling 2011-10-06 12:47:04 +02:00
sched_stats.h locking, sched: Annotate thread_group_cputimer as raw 2011-09-13 11:11:55 +02:00
sched_stoptask.c
seccomp.c
semaphore.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
signal.c threadgroup: extend threadgroup_lock() to cover exit and exec 2011-12-12 18:12:21 -08:00
smp.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
softirq.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
spinlock.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
srcu.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
stacktrace.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
stop_machine.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
sys.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
sys_ni.c Cross Memory Attach 2011-10-31 17:30:44 -07:00
sysctl.c Merge branch 'akpm' (Andrew's incoming) 2011-10-31 17:46:07 -07:00
sysctl_binary.c ipv4: NET_IPV4_ROUTE_GC_INTERVAL removal 2011-10-03 14:13:01 -04:00
sysctl_check.c
taskstats.c Make TASKSTATS require root access 2011-09-19 17:04:37 -07:00
test_kprobes.c
time.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
timeconst.pl
timer.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
tracepoint.c
tsacct.c Make taskstats round statistics down to nearest 1k bytes/events 2011-09-19 17:10:57 -07:00
uid16.c
up.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
user-return-notifier.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
user.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
user_namespace.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
utsname.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
utsname_sysctl.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
wait.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
watchdog.c watchdog: move watchdog_*_all_cpus under CONFIG_SYSCTL 2011-10-31 17:30:53 -07:00
workqueue.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
workqueue_sched.h