linux/drivers/tty
Michal Hocko d75da004c7 oom: improve oom disable handling
Tetsuo has reported that sysrq triggered OOM killer will print a
misleading information when no tasks are selected:

  sysrq: SysRq : Manual OOM execution
  Out of memory: Kill process 4468 ((agetty)) score 0 or sacrifice child
  Killed process 4468 ((agetty)) total-vm:43704kB, anon-rss:1760kB, file-rss:0kB, shmem-rss:0kB
  sysrq: SysRq : Manual OOM execution
  Out of memory: Kill process 4469 (systemd-cgroups) score 0 or sacrifice child
  Killed process 4469 (systemd-cgroups) total-vm:10704kB, anon-rss:120kB, file-rss:0kB, shmem-rss:0kB
  sysrq: SysRq : Manual OOM execution
  sysrq: OOM request ignored because killer is disabled
  sysrq: SysRq : Manual OOM execution
  sysrq: OOM request ignored because killer is disabled
  sysrq: SysRq : Manual OOM execution
  sysrq: OOM request ignored because killer is disabled

The real reason is that there are no eligible tasks for the OOM killer
to select but since commit 7c5f64f844 ("mm: oom: deduplicate victim
selection code for memcg and global oom") the semantic of out_of_memory
has changed without updating moom_callback.

This patch updates moom_callback to tell that no task was eligible which
is the case for both oom killer disabled and no eligible tasks.  In
order to help distinguish first case from the second add printk to both
oom_killer_{enable,disable}.  This information is useful on its own
because it might help debugging potential memory allocation failures.

Fixes: 7c5f64f844 ("mm: oom: deduplicate victim selection code for memcg and global oom")
Link: http://lkml.kernel.org/r/20170404134705.6361-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:10 -07:00
..
hvc tty: Remove extra include in HVC console tty framework 2017-02-10 16:01:45 +01:00
ipwireless tty: ipwireless, cleanup TIOCGSERIAL 2016-06-25 08:56:30 -07:00
serdev serdev: implement get/set tiocm 2017-04-12 22:12:17 +02:00
serial tty: serial: omap: add UPF_BOOT_AUTOCONF flag for DT init 2017-04-12 22:12:16 +02:00
vt sched/headers: Remove duplicate #include <linux/sched/debug.h> line 2017-03-28 09:56:03 +02:00
amiserial.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
bfin_jtag_comm.c
cyclades.c tty: stop defining STD_COM_FLAGS in drivers 2016-06-25 08:56:30 -07:00
ehv_bytechan.c
goldfish.c tty: goldfish: Fix a parameter of a call to free_irq 2017-01-12 11:51:25 +01:00
isicom.c
Kconfig devpts: Make each mount of devpts an independent filesystem. 2016-06-05 10:36:01 -07:00
Makefile serdev: Introduce new bus for serial attached devices 2017-02-03 10:17:02 +01:00
metag_da.c timers, drivers/tty/metag_da: Initialize the poll timer as pinned 2016-07-07 10:25:14 +02:00
mips_ejtag_fdc.c timers, drivers/tty/mips_ejtag: Initialize the poll timer as pinned 2016-07-07 10:34:59 +02:00
moxa.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
moxa.h
mxser.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mxser.h
n_gsm.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
n_hdlc.c tty: n_hdlc: get rid of racy n_hdlc.tbuf 2017-03-07 18:54:30 +01:00
n_r3964.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c Fix OpenSSH pty regression on close 2016-05-01 13:22:54 -07:00
nozomi.c tty: nozomi: avoid sprintf buffer overflow 2016-11-29 20:20:07 +01:00
pty.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
rocket_int.h
rocket.c tty: rocket: fix invalid user-pointer checks 2016-11-10 14:41:25 +01:00
rocket.h
synclink_gt.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
synclink.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
synclinkmp.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sysrq.c oom: improve oom disable handling 2017-05-03 15:52:10 -07:00
tty_audit.c
tty_buffer.c tty_port: Add port client functions 2017-02-03 10:17:02 +01:00
tty_io.c tty: fix comment for __tty_alloc_driver() 2017-04-24 13:15:39 +02:00
tty_ioctl.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
tty_ldisc.c Revert "tty: don't panic on OOM in tty_set_ldisc()" 2017-04-14 10:59:56 +02:00
tty_ldsem.c sched/headers: Prepare to move the get_task_struct()/put_task_struct() and related APIs from <linux/sched.h> to <linux/sched/task.h> 2017-03-02 08:42:40 +01:00
tty_mutex.c
tty_port.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00