linux/kernel
Michal Hocko ec8d7c14ea mm, oom_reaper: do not mmput synchronously from the oom reaper context
Tetsuo has properly noted that mmput slow path might get blocked waiting
for another party (e.g.  exit_aio waits for an IO).  If that happens the
oom_reaper would be put out of the way and will not be able to process
next oom victim.  We should strive for making this context as reliable
and independent on other subsystems as much as possible.

Introduce mmput_async which will perform the slow path from an async
(WQ) context.  This will delay the operation but that shouldn't be a
problem because the oom_reaper has reclaimed the victim's address space
for most cases as much as possible and the remaining context shouldn't
bind too much memory anymore.  The only exception is when mmap_sem
trylock has failed which shouldn't happen too often.

The issue is only theoretical but not impossible.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00
..
bpf Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-05-18 11:51:59 -07:00
configs
debug mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings 2016-02-22 08:51:37 +01:00
events Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-05-17 16:26:30 -07:00
gcov gcov: use within_module() helper. 2015-12-04 22:46:25 +01:00
irq This is the bulk of GPIO changes for kernel cycle v4.7: 2016-05-17 17:39:42 -07:00
livepatch Merge branches 'for-4.7/core', 'for-4.7/livepatching-doc' and 'for-4.7/livepatching-ppc64' into for-linus 2016-05-17 12:06:35 +02:00
locking Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-05-16 14:47:16 -07:00
power PM / Hibernate: Call flush_icache_range() on pages restored in-place 2016-04-28 13:35:48 +01:00
printk printk: add clear_idx symbol to vmcoreinfo 2016-03-17 15:09:34 -07:00
rcu debugobjects: insulate non-fixup logic related to static obj from fixup callbacks 2016-05-19 19:12:14 -07:00
sched Power management material for v4.7-rc1 2016-05-16 19:17:22 -07:00
time debugobjects: insulate non-fixup logic related to static obj from fixup callbacks 2016-05-19 19:12:14 -07:00
trace powerpc updates for 4.7 2016-05-20 10:12:41 -07:00
.gitignore certs: add .gitignore to stop git nagging about x509_certificate_list 2015-10-21 15:18:35 +01:00
acct.c
async.c async: export current_is_async() 2015-11-19 17:51:48 +01:00
audit_fsnotify.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
audit_tree.c audit: cleanup prune_tree_thread 2016-04-04 09:46:47 -04:00
audit_watch.c don't bother with ->d_inode->i_sb - it's always equal to ->d_sb 2016-04-10 17:11:51 -04:00
audit.c Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit 2016-05-18 18:46:55 -07:00
audit.h security: Make inode argument of inode_getsecid non-const 2015-12-24 11:09:39 -05:00
auditfilter.c audit: Fix typo in comment 2016-02-08 11:25:39 -05:00
auditsc.c Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit 2016-05-18 18:46:55 -07:00
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends 2015-12-03 10:24:08 -05:00
cgroup_pids.c cgroup_pids: fix a typo. 2015-12-14 14:54:37 -05:00
cgroup.c cgroup: fix compile warning 2016-05-12 11:05:27 -04:00
compat.c
configs.c
context_tracking.c context_tracking: Switch to new static_branch API 2015-11-24 09:56:43 +01:00
cpu_pm.c kernel/cpu_pm: fix cpu_cluster_pm_exit comment 2015-09-03 02:42:20 +02:00
cpu.c sched/hotplug: Make activate() the last hotplug step 2016-05-06 14:58:25 +02:00
cpuset.c cpuset: use static key better and convert to new API 2016-05-19 19:12:14 -07:00
crash_dump.c
cred.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
delayacct.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
dma.c
elfcore.c
exec_domain.c
exit.c oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space 2016-03-25 16:37:42 -07:00
extable.c kernel/extable.c: remove duplicated include 2015-09-10 13:29:01 -07:00
fork.c mm, oom_reaper: do not mmput synchronously from the oom reaper context 2016-05-20 17:58:30 -07:00
freezer.c
futex_compat.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-01-20 17:09:18 -08:00
futex.c futex: Acknowledge a new waiter in counter before plist 2016-04-21 11:06:09 +02:00
groups.c
hung_task.c kernel/hung_task.c: use timeout diff when timeout is updated 2016-03-22 15:36:02 -07:00
irq_work.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
jump_label.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
kallsyms.c kallsyms: add support for relative offsets in kallsyms address table 2016-03-15 16:55:16 -07:00
kcmp.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-01-20 17:09:18 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: don't profile branches in kcov 2016-04-28 19:34:04 -07:00
kexec_core.c mm: rename _count, field of the struct page, to _refcount 2016-05-19 19:12:14 -07:00
kexec_file.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-03-17 11:33:45 -07:00
kexec_internal.h kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE 2016-01-20 17:09:18 -08:00
kexec.c kexec: set KEXEC_TYPE_CRASH before sanity_check_segment_list() 2016-01-20 17:09:18 -08:00
kmod.c kmod: don't run async usermode helper as a child of kworker thread 2015-10-23 17:55:10 +09:00
kprobes.c perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe 2015-08-04 10:16:54 +02:00
ksysfs.c rcu: Remove TINY_RCU bloat from pointless boot parameters 2015-12-07 16:59:37 -08:00
kthread.c kernel/kthread.c:kthread_create_on_node(): clarify documentation 2015-09-04 16:54:41 -07:00
latencytop.c sched/debug: Make schedstats a runtime tunable that is disabled by default 2016-02-09 11:54:23 +01:00
Makefile kernel: add kcov code coverage 2016-03-22 15:36:02 -07:00
membarrier.c sys_membarrier(): system-wide memory barrier (generic, x86) 2015-09-11 15:21:34 -07:00
memremap.c memremap: add arch specific hook for MEMREMAP_WB mappings 2016-04-04 10:26:41 +02:00
module_signing.c KEYS: Move the point of trust determination to __key_link() 2016-04-11 22:43:43 +01:00
module-internal.h
module.c module: preserve Elf information for livepatch modules 2016-04-01 15:00:10 +02:00
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 cgroup: introduce cgroup namespaces 2016-02-16 13:04:58 -05:00
padata.c kernel/padata.c: hide unused functions 2016-05-19 19:12:14 -07:00
panic.c panic: change nmi_panic from macro to function 2016-03-22 15:36:02 -07:00
params.c Nothing exciting, minor tweaks and cleanups. 2015-11-09 15:53:39 -08:00
pid_namespace.c
pid.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-01-31 15:44:04 -08:00
profile.c profile: hide unused functions when !CONFIG_PROC_FS 2016-03-22 15:36:02 -07:00
ptrace.c ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock 2016-03-22 15:36:02 -07:00
range.c
reboot.c kexec: split kexec_load syscall from kexec core code 2015-09-10 13:29:01 -07:00
relay.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
resource.c /proc/iomem: only expose physical resource addresses to privileged users 2016-04-14 12:56:09 -07:00
seccomp.c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-05-19 10:02:26 -07:00
signal.c signals/sigaltstack: Report current flag bits in sigaltstack() 2016-05-04 08:34:14 +02:00
smp.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 13:50:29 -07:00
smpboot.c cpu/hotplug: Unpark smpboot threads from the state machine 2016-03-01 20:36:56 +01:00
smpboot.h cpu/hotplug: Create hotplug threads 2016-03-01 20:36:56 +01:00
softirq.c arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
stacktrace.c
stop_machine.c kernel/stop_machine.c: remove CONFIG_SMP dependencies 2016-01-16 11:17:24 -08:00
sys_ni.c vfs: add copy_file_range syscall and vfs helper 2015-12-01 14:00:53 -05:00
sys.c timer: convert timer_slack_ns from unsigned long to u64 2016-03-17 15:09:34 -07:00
sysctl_binary.c fs/coredump: prevent fsuid=0 dumps into user-controlled directories 2016-03-22 15:36:02 -07:00
sysctl.c mm: /proc/sys/vm/stat_refresh to force vmstat update 2016-05-19 19:12:14 -07:00
task_work.c task_work: remove fifo ordering guarantee 2015-09-05 13:46:58 -07:00
taskstats.c taskstats: use the libnl API to align nlattr on 64-bit 2016-04-23 20:13:25 -04:00
test_kprobes.c
torture.c rcutorture: Dump trace buffer upon shutdown 2016-04-21 13:47:04 -07:00
tracepoint.c kernel/...: convert pr_warning to pr_warn 2016-03-22 15:36:02 -07:00
tsacct.c time, acct: Drop irq save & restore from __acct_update_integrals() 2016-02-29 09:53:09 +01:00
uid16.c
up.c
user_namespace.c kernel/*: switch to memdup_user_nul() 2016-01-04 10:27:55 -05:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c watchdog: don't run proc_watchdog_update if new value is same as old 2016-03-17 15:09:34 -07:00
workqueue_internal.h sched/core: Get rid of 'cpu' argument in wq_worker_sleeping() 2016-03-02 10:28:47 -05:00
workqueue.c debugobjects: insulate non-fixup logic related to static obj from fixup callbacks 2016-05-19 19:12:14 -07:00