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0c986253b9
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Tejun Heo 0c986253b9 Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem" 
This reverts commit d59cfc09c3.

d59cfc09c3 ("sched, cgroup: replace signal_struct->group_rwsem with
a global percpu_rwsem") and b5ba75b5fc ("cgroup: simplify
threadgroup locking") changed how cgroup synchronizes against task
fork and exits so that it uses global percpu_rwsem instead of
per-process rwsem; unfortunately, the write [un]lock paths of
percpu_rwsem always involve synchronize_rcu_expedited() which turned
out to be too expensive.

Improvements for percpu_rwsem are scheduled to be merged in the coming
v4.4-rc1 merge window which alleviates this issue.  For now, revert
the two commits to restore per-process rwsem.  They will be re-applied
for the v4.4-rc1 merge window.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org # v4.2+
2015-09-16 11:51:12 -04:00
..
bpf bpf: fix out of bounds access in verifier log 2015-09-09 14:11:55 -07:00
configs kconfig: add xenconfig defconfig helper 2015-06-16 11:04:29 +01:00
debug debug: prevent entering debug mode on panic/exception. 2015-02-19 12:39:03 -06:00
events kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
gcov gcov: add support for GCC 5.1 2015-06-30 19:44:57 -07:00
irq Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 14:33:35 -07:00
livepatch livepatch: Improve error handling in klp_disable_func() 2015-07-14 22:48:06 +02:00
locking Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
power Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block 2015-09-02 13:10:25 -07:00
printk kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
rcu rcu,locking: Privatize smp_mb__after_unlock_lock() 2015-08-04 08:49:21 -07:00
sched userfaultfd: waitqueue: add nr wake parameter to __wake_up_locked_key 2015-09-04 16:54:41 -07:00
time Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 14:04:50 -07:00
trace Mostly this is just clean ups and micro optimizations. 2015-09-08 14:04:14 -07:00
.gitignore
acct.c acct: check FMODE_CAN_WRITE 2015-04-11 22:27:55 -04:00
async.c
audit_fsnotify.c audit: clean simple fsnotify implementation 2015-08-06 16:14:53 -04:00
audit_tree.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-09-08 13:34:59 -07:00
audit_watch.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-09-08 13:34:59 -07:00
audit.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-09-08 13:34:59 -07:00
audit.h Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-09-08 13:34:59 -07:00
auditfilter.c audit: implement audit by executable 2015-08-06 16:17:25 -04:00
auditsc.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-09-08 13:34:59 -07:00
backtracetest.c
bounds.c
capability.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
cgroup_freezer.c cgroup: allow a cgroup subsystem to reject a fork 2015-07-14 17:29:23 -04:00
cgroup_pids.c cgroup: pids: fix invalid get/put usage 2015-08-25 14:19:25 -04:00
cgroup.c Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem" 2015-09-16 11:51:12 -04:00
compat.c compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap() 2015-06-04 23:57:18 +02:00
configs.c
context_tracking.c context_tracking: Inherit TIF_NOHZ through forks instead of context switches 2015-05-07 12:02:51 +02:00
cpu_pm.c kernel/cpu_pm: fix cpu_cluster_pm_exit comment 2015-09-03 02:42:20 +02:00
cpu.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-08-31 20:26:22 -07:00
cpuset.c cpuset: use trialcs->mems_allowed as a temp variable 2015-08-10 11:18:41 -04:00
crash_dump.c
cred.c kernel/cred.c: remove unnecessary kdebug atomic reads 2015-09-10 13:29:01 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c Remove rest of exec domains. 2015-04-12 21:03:31 +02:00
exit.c kernel: exit: fix typo in comment 2015-08-07 13:59:49 +02:00
extable.c kernel/extable.c: remove duplicated include 2015-09-10 13:29:01 -07:00
fork.c Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem" 2015-09-16 11:51:12 -04:00
freezer.c
futex_compat.c
futex.c futex: Make should_fail_futex() static 2015-07-20 21:43:54 +02:00
groups.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
hung_task.c kernel/hung_task.c: change hung_task.c to use for_each_process_thread() 2015-04-15 16:35:22 -07:00
irq_work.c
jump_label.c locking/static_keys: Add selftest 2015-08-03 11:34:16 +02:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS 2015-05-12 09:46:00 +02:00
Kconfig.preempt
kexec_core.c kexec: export KERNEL_IMAGE_SIZE to vmcoreinfo 2015-09-10 13:29:01 -07:00
kexec_file.c kexec: split kexec_file syscall code to kexec_file.c 2015-09-10 13:29:01 -07:00
kexec_internal.h kexec: split kexec_file syscall code to kexec_file.c 2015-09-10 13:29:01 -07:00
kexec.c kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
kmod.c kmod: handle UMH_WAIT_PROC from system unbound workqueue 2015-09-10 13:29:01 -07:00
kprobes.c perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe 2015-08-04 10:16:54 +02:00
ksysfs.c kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
kthread.c kernel/kthread.c:kthread_create_on_node(): clarify documentation 2015-09-04 16:54:41 -07:00
latencytop.c
Makefile sys_membarrier(): system-wide memory barrier (generic, x86) 2015-09-11 15:21:34 -07:00
membarrier.c sys_membarrier(): system-wide memory barrier (generic, x86) 2015-09-11 15:21:34 -07:00
memremap.c add devm_memremap_pages 2015-08-27 19:40:58 -04:00
module_signing.c PKCS#7: Appropriately restrict authenticated attributes and content type 2015-08-12 17:01:01 +01:00
module-internal.h
module.c module: weaken locking assertion for oops path. 2015-07-29 06:13:22 +09:30
notifier.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 08:40:25 -07:00
nsproxy.c
padata.c padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:38 -08:00
panic.c kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path 2015-06-30 19:44:57 -07:00
params.c Minor merge needed, due to function move. 2015-07-01 10:49:25 -07:00
pid_namespace.c
pid.c rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN() 2015-07-22 15:27:32 -07:00
profile.c mm: rename alloc_pages_exact_node() to __alloc_pages_node() 2015-09-08 15:35:28 -07:00
ptrace.c seccomp: add ptrace options for suspend/resume 2015-07-15 11:52:52 -07:00
range.c kernel: avoid overflow in cmp_range 2015-01-17 10:02:23 +13:00
reboot.c kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
relay.c kernel/relay.c: use kvfree() in relay_free_page_array() 2015-06-30 19:44:59 -07:00
resource.c mm: enhance region_is_ram() to region_intersects() 2015-08-10 23:07:05 -04:00
seccomp.c Merge tag 'seccomp-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into next 2015-07-20 17:19:19 +10:00
signal.c signal: fix information leak in copy_siginfo_to_user 2015-08-07 04:39:40 +03:00
smp.c smp: Fix error case handling in smp_call_function_*() 2015-04-19 13:19:23 -07:00
smpboot.c smpboot: allow passing the cpumask on per-cpu thread registration 2015-09-04 16:54:41 -07:00
smpboot.h
softirq.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-02-09 15:24:03 -08:00
stacktrace.c
stop_machine.c stop_machine: Remove cpu_stop_work's from list in cpu_stop_park() 2015-08-03 12:21:28 +02:00
sys_ni.c sys_membarrier(): system-wide memory barrier (generic, x86) 2015-09-11 15:21:34 -07:00
sys.c vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
sysctl_binary.c
sysctl.c sysctl: fix int -> unsigned long assignments in INT_MIN case 2015-09-10 13:29:01 -07:00
task_work.c task_work: remove fifo ordering guarantee 2015-09-05 13:46:58 -07:00
taskstats.c netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
test_kprobes.c
torture.c rcu: Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE() 2015-05-27 12:56:15 -07:00
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c capabilities: ambient capabilities 2015-09-04 16:54:41 -07:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c watchdog: rename watchdog_suspend() and watchdog_resume() 2015-09-04 16:54:41 -07:00
workqueue_internal.h
workqueue.c Merge branch 'for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2015-09-02 08:02:20 -07:00