Johannes Weiner 3c606d35fe cgroup: prevent mount hang due to memory controller lifetime ... Since b2052564e6 ("mm: memcontrol: continue cache reclaim from offlined groups"), re-mounting the memory controller after using it is very likely to hang. The cgroup core assumes that any remaining references after deleting a cgroup are temporary in nature, and synchroneously waits for them, but the above-mentioned commit has left-over page cache pin its css until it is reclaimed naturally. That being said, swap entries and charged kernel memory have been doing the same indefinite pinning forever, the bug is just more likely to trigger with left-over page cache. Reparenting kernel memory is highly impractical, which leaves changing the cgroup assumptions to reflect this: once a controller has been mounted and used, it has internal state that is independent from mount and cgroup lifetime. It can be unmounted and remounted, but it can't be reconfigured during subsequent mounts. Don't offline the controller root as long as there are any children, dead or alive. A remount will no longer wait for these old references to drain, it will simply mount the persistent controller state again. Reported-by: "Suzuki K. Poulose" <Suzuki.Poulose@arm.com> Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>		2015-01-22 10:26:43 -05:00
..
bpf	bpf: verifier: add checks for BPF_ABS | BPF_IND instructions	2014-12-05 21:47:32 -08:00
configs
debug	kdb: replace strnicmp with strncasecmp	2014-10-14 02:18:25 +02:00
events	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-19 13:15:24 -08:00
gcov	gcov: enable GCOV_PROFILE_ALL from ARCH Kconfigs	2014-12-13 12:42:51 -08:00
irq	genirq: Prevent proc race against freeing of irq descriptors	2014-12-13 13:33:07 +01:00
locking	locking/mutex: Don't assume TASK_RUNNING	2014-10-28 10:55:08 +01:00
power	PM: Eliminate CONFIG_PM_RUNTIME	2014-12-19 22:55:06 +01:00
printk	This code is a fork from the trace-3.19 pull as it needed the trace_seq	2014-12-13 14:04:41 -08:00
rcu	Merge branches 'torture.2014.11.03a', 'cpu.2014.11.03a', 'doc.2014.11.13a', 'fixes.2014.11.13a', 'signal.2014.10.29a' and 'rt.2014.10.29a' into HEAD	2014-11-13 10:39:04 -08:00
sched	sched_show_task: fix unsafe usage of ->real_parent	2014-12-10 17:41:09 -08:00
time	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-19 13:29:20 -08:00
trace	More ACPI and power management updates for 3.19-rc1	2014-12-18 20:28:33 -08:00
.gitignore
acct.c	acct: eliminate compile warning	2014-10-09 22:26:04 -04:00
async.c	kernel/async.c: switch to pr_foo()	2014-10-09 22:26:04 -04:00
audit_tree.c	fsnotify: unify inode and mount marks handling	2014-12-13 12:42:53 -08:00
audit_watch.c	audit: invalid op= values for rules	2014-09-23 16:37:53 -04:00
audit.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2014-12-13 13:41:28 -08:00
audit.h	audit: reduce scope of audit_log_fcaps	2014-09-23 16:37:51 -04:00
auditfilter.c	Merge git://git.infradead.org/users/eparis/audit	2014-10-19 16:25:56 -07:00
auditsc.c	new helper: audit_file()	2014-11-19 13:01:26 -05:00
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c	cgroup: prevent mount hang due to memory controller lifetime	2015-01-22 10:26:43 -05:00
compat.c	compat: nanosleep: Clarify error handling	2014-09-06 12:58:18 +02:00
configs.c
context_tracking.c	sched: stop the unbound recursion in preempt_schedule_context()	2014-10-28 10:46:05 +01:00
cpu_pm.c
cpu.c	cpu: Avoid puts_pending overflow	2014-11-03 19:21:01 -08:00
cpuset.c	Merge branch 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2014-12-11 18:57:19 -08:00
crash_dump.c	crash_dump: Make is_kdump_kernel() accessible from modules	2014-08-25 15:42:19 -07:00
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	TTY/Serial driver patches for 3.19-rc1	2014-12-14 15:23:32 -08:00
extable.c	ftrace/x86/extable: Add is_ftrace_trampoline() function	2014-11-19 15:25:26 -05:00
fork.c	mm: use new helper functions around the i_mmap_mutex	2014-12-13 12:42:45 -08:00
freezer.c	freezer: remove obsolete comments in __thaw_task()	2014-10-21 23:44:20 +02:00
futex_compat.c
futex.c	futex: Fix a race condition between REQUEUE_PI and task death	2014-10-26 16:16:18 +01:00
groups.c	userns: Don't allow setgroups until a gid mapping has been setablished	2014-12-09 16:58:40 -06:00
hung_task.c
irq_work.c	percpu: Convert remaining __get_cpu_var uses in 3.18-rcX	2014-10-29 11:18:18 -04:00
jump_label.c
kallsyms.c	kernel/kallsyms.c: use __seq_open_private()	2014-10-14 02:18:16 +02:00
kcmp.c	kcmp: fix standard comparison bug	2014-09-10 15:42:12 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c	kexec: remove unnecessary KERN_ERR from kexec.c	2014-12-13 12:42:51 -08:00
kmod.c	usermodehelper: kill the kmod_thread_locker logic	2014-12-10 17:41:17 -08:00
kprobes.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux	2014-12-11 17:30:55 -08:00
ksysfs.c
kthread.c	kernel/kthread.c: partial revert of 81c98869fa ("kthread: ensure locality of task_struct allocations")	2014-10-09 22:25:51 -04:00
latencytop.c
Makefile	kernel: res_counter: remove the unused API	2014-12-10 17:41:04 -08:00
module_signing.c
module-internal.h
module.c	The exciting thing here is the getting rid of stop_machine on module	2014-12-18 20:55:41 -08:00
notifier.c
nsproxy.c	bury struct proc_ns in fs/proc	2014-12-04 14:34:54 -05:00
padata.c
panic.c	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
params.c	param: do not set store func without write perm	2014-12-18 12:38:51 +10:30
pid_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-16 15:53:03 -08:00
pid.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-16 15:53:03 -08:00
profile.c
ptrace.c	exit: ptrace: shift "reap dead" code from exit_ptrace() to forget_original_parent()	2014-12-10 17:41:10 -08:00
range.c
reboot.c	kernel: add support for kernel restart handler call chain	2014-09-26 00:00:06 -07:00
relay.c
resource.c	x86: optimize resource lookups for ioremap	2014-10-14 02:18:22 +02:00
seccomp.c	Merge branch 'x86-seccomp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-10-14 02:27:06 +02:00
signal.c	Merge branch 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-10 09:34:43 -08:00
smp.c	Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2014-10-15 07:48:18 +02:00
smpboot.c	sched, smp: Correctly deal with nested sleeps	2014-10-28 10:56:24 +01:00
smpboot.h
softirq.c	rcu: Remove "cpu" argument to rcu_note_context_switch()	2014-11-03 19:20:34 -08:00
stacktrace.c	stacktrace: introduce snprint_stack_trace for buffer output	2014-12-13 12:42:48 -08:00
stop_machine.c
sys_ni.c	syscalls: implement execveat() system call	2014-12-13 12:42:51 -08:00
sys.c	x86, mpx: On-demand kernel allocation of bounds tables	2014-11-18 00:58:53 +01:00
sysctl_binary.c	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
sysctl.c	As the merge window is still open, and this code was not as complex	2014-12-16 12:53:59 -08:00
system_certificates.S
system_keyring.c
task_work.c
taskstats.c	kill f_dentry uses	2014-11-19 13:01:25 -05:00
test_kprobes.c
torture.c	torture: Address race in module cleanup	2014-09-16 13:41:06 -07:00
tracepoint.c
tsacct.c
uid16.c	groups: Consolidate the setgroups permission checks	2014-12-05 17:19:27 -06:00
up.c
user_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-12-17 12:31:40 -08:00
user-return-notifier.c	scheduler: Replace __get_cpu_var with this_cpu_ptr	2014-08-26 13:45:45 -04:00
user.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-12-17 12:31:40 -08:00
utsname_sysctl.c
utsname.c	copy address of proc_ns_ops into ns_common	2014-12-04 14:34:47 -05:00
watchdog.c	Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2014-10-15 07:48:18 +02:00
workqueue_internal.h
workqueue.c	workqueue: allow rescuer thread to do more work.	2014-12-08 12:39:16 -05:00