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Commit 158e0a2d1b3cffed8b46cbc56393a1394672ef79

Authored by KAMEZAWA Hiroyuki
Committed by Linus Torvalds
1 parent 73045c47b6
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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: KAMEZAWA 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: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 3 changed files with 10 additions and 4 deletions Side-by-side Diff

... ... @@ -66,6 +66,8 @@
66 66 extern unsigned long badness(struct task_struct *p, struct mem_cgroup *mem,
67 67 const nodemask_t *nodemask, unsigned long uptime);
68 68  
  69 +extern struct task_struct *find_lock_task_mm(struct task_struct *p);
  70 +
69 71 /* sysctls */
70 72 extern int sysctl_oom_dump_tasks;
71 73 extern int sysctl_oom_kill_allocating_task;
... ... @@ -47,6 +47,7 @@
47 47 #include <linux/mm_inline.h>
48 48 #include <linux/page_cgroup.h>
49 49 #include <linux/cpu.h>
  50 +#include <linux/oom.h>
50 51 #include "internal.h"
51 52  
52 53 #include <asm/uaccess.h>
53 54  
... ... @@ -838,10 +839,13 @@
838 839 {
839 840 int ret;
840 841 struct mem_cgroup *curr = NULL;
  842 + struct task_struct *p;
841 843  
842   - task_lock(task);
843   - curr = try_get_mem_cgroup_from_mm(task->mm);
844   - task_unlock(task);
  844 + p = find_lock_task_mm(task);
  845 + if (!p)
  846 + return 0;
  847 + curr = try_get_mem_cgroup_from_mm(p->mm);
  848 + task_unlock(p);
845 849 if (!curr)
846 850 return 0;
847 851 /*
... ... @@ -106,7 +106,7 @@
106 106 * pointer. Return p, or any of its subthreads with a valid ->mm, with
107 107 * task_lock() held.
108 108 */
109   -static struct task_struct *find_lock_task_mm(struct task_struct *p)
  109 +struct task_struct *find_lock_task_mm(struct task_struct *p)
110 110 {
111 111 struct task_struct *t = p;
112 112