Commit 158e0a2d authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
Browse files

memcg: use find_lock_task_mm() in memory cgroups oom 



When the OOM killer scans task, it check a task is under memcg or
not when it's called via memcg's context.

But, as Oleg pointed out, a thread group leader may have NULL ->mm
and task_in_mem_cgroup() may do wrong decision. We have to use
find_lock_task_mm() in memcg as generic OOM-Killer does.

Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 73045c47

include/linux/oom.h

+2 −0
Original line number Diff line number Diff line
@@ -66,6 +66,8 @@ static inline void oom_killer_enable(void) 
extern unsigned long badness(struct task_struct *p, struct mem_cgroup *mem,

		      const nodemask_t *nodemask, unsigned long uptime);



extern struct task_struct *find_lock_task_mm(struct task_struct *p);



/* sysctls */

extern int sysctl_oom_dump_tasks;

extern int sysctl_oom_kill_allocating_task;

mm/memcontrol.c

+7 −3
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <linux/mm_inline.h>

#include <linux/page_cgroup.h>

#include <linux/cpu.h>

#include <linux/oom.h>

#include "internal.h"



#include <asm/uaccess.h>
@@ -838,10 +839,13 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) 
{

	int ret;

	struct mem_cgroup *curr = NULL;

	struct task_struct *p;



	task_lock(task);

	curr = try_get_mem_cgroup_from_mm(task->mm);

	task_unlock(task);

	p = find_lock_task_mm(task);

	if (!p)

		return 0;

	curr = try_get_mem_cgroup_from_mm(p->mm);

	task_unlock(p);

	if (!curr)

		return 0;

	/*

mm/oom_kill.c

+1 −1
Original line number Diff line number Diff line
@@ -106,7 +106,7 @@ static void boost_dying_task_prio(struct task_struct *p, 
 * pointer.  Return p, or any of its subthreads with a valid ->mm, with

 * task_lock() held.

 */

static struct task_struct *find_lock_task_mm(struct task_struct *p)

struct task_struct *find_lock_task_mm(struct task_struct *p)

{

	struct task_struct *t = p;

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