linux/fs/proc
Michal Hocko b2b469939e proc, oom: do not report alien mms when setting oom_score_adj
Tetsuo has reported that creating a thousands of processes sharing MM
without SIGHAND (aka alien threads) and setting
/proc/<pid>/oom_score_adj will swamp the kernel log and takes ages [1]
to finish.  This is especially worrisome that all that printing is done
under RCU lock and this can potentially trigger RCU stall or softlockup
detector.

The primary reason for the printk was to catch potential users who might
depend on the behavior prior to 44a70adec9 ("mm, oom_adj: make sure
processes sharing mm have same view of oom_score_adj") but after more
than 2 years without a single report I guess it is safe to simply remove
the printk altogether.

The next step should be moving oom_score_adj over to the mm struct and
remove all the tasks crawling as suggested by [2]

[1] http://lkml.kernel.org/r/97fce864-6f75-bca5-14bc-12c9f890e740@i-love.sakura.ne.jp
[2] http://lkml.kernel.org/r/20190117155159.GA4087@dhcp22.suse.cz

Link: http://lkml.kernel.org/r/20190212102129.26288-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Yong-Taek Lee <ytk.lee@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-21 09:01:00 -08:00
..
Kconfig proc/kcore: add vmcoreinfo note to /proc/kcore 2018-08-22 10:52:46 -07:00
Makefile proc: : uninline name_to_int() 2017-11-17 16:10:00 -08:00
array.c mm, proc: report PR_SET_THP_DISABLE in proc 2018-12-28 12:11:50 -08:00
base.c proc, oom: do not report alien mms when setting oom_score_adj 2019-02-21 09:01:00 -08:00
cmdline.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
consoles.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
cpuinfo.c x86 / CPU: Always show current CPU frequency in /proc/cpuinfo 2017-11-15 19:46:50 +01:00
devices.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
fd.c proc: use "unsigned int" in proc_fill_cache() 2018-06-07 17:34:38 -07:00
fd.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
generic.c proc: fix /proc/net/* after setns(2) 2019-02-01 15:46:22 -08:00
inode.c fs/proc/inode.c: delete unnecessary variable in proc_alloc_inode() 2019-01-04 13:13:45 -08:00
internal.h proc: fix /proc/net/* after setns(2) 2019-02-01 15:46:22 -08:00
interrupts.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
kcore.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
kmsg.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
loadavg.c sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD 2018-10-26 16:26:32 -07:00
meminfo.c mm, proc: add KReclaimable to /proc/meminfo 2018-10-26 16:26:32 -07:00
namespaces.c procfs: switch instantiate_t to d_splice_alias() 2018-05-26 14:20:50 -04:00
nommu.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
page.c /proc/kpagecount: return 0 for special pages that are never mapped 2018-12-28 12:11:50 -08:00
proc_net.c proc: fix /proc/net/* after setns(2) 2019-02-01 15:46:22 -08:00
proc_sysctl.c proc/sysctl: don't return ENOMEM on lookup when a table is unregistering 2018-12-13 20:59:44 -05:00
proc_tty.c tty: replace ->proc_fops with ->proc_show 2018-05-16 07:24:30 +02:00
root.c proc: Make inline name size calculation automatic 2018-06-15 00:48:57 -04:00
self.c proc: introduce a proc_pid_ns helper 2018-05-16 07:23:35 +02:00
softirqs.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
stat.c proc: use "unsigned int" in /proc/stat hook 2018-08-22 10:52:46 -07:00
task_mmu.c mm: proc: smaps_rollup: fix pss_locked calculation 2019-02-12 16:33:18 -08:00
task_nommu.c mm: /proc/pid/*maps remove is_pid and related wrappers 2018-08-22 10:52:44 -07:00
thread_self.c proc: introduce a proc_pid_ns helper 2018-05-16 07:23:35 +02:00
uptime.c fs/proc/uptime.c: use ktime_get_boottime_ts64 2018-08-22 10:52:45 -07:00
util.c fs/proc/util.c: include fs/proc/internal.h for name_to_int() 2019-01-04 13:13:45 -08:00
version.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
vmcore.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00