>From 2da51204250a2f1127792f98c12436771c07b67d Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Fri, 8 Jul 2016 00:41:38 +0900
Subject: [PATCH 5/6] mm,oom: Remove OOM_SCAN_ABORT case and signal_struct->oom_victims.
Since oom_has_pending_mm() controls whether to select next OOM victim,
we no longer need to abort OOM victim selection loop using OOM_SCAN_ABORT
case. Also, since signal_struct->oom_victims was used only for allowing
oom_scan_process_thread() to return OOM_SCAN_ABORT, we no longer need to
use signal_struct->oom_victims.
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
include/linux/oom.h | 1 -
include/linux/sched.h | 1 -
mm/memcontrol.c | 8 --------
mm/oom_kill.c | 26 +-------------------------
4 files changed, 1 insertion(+), 35 deletions(-)
diff --git a/include/linux/oom.h b/include/linux/oom.h
index cb3f041..27be4ba 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -49,7 +49,6 @@ enum oom_constraint {
enum oom_scan_t {
OOM_SCAN_OK, /* scan thread and find its badness */
OOM_SCAN_CONTINUE, /* do not consider thread for oom kill */
- OOM_SCAN_ABORT, /* abort the iteration and return */
OOM_SCAN_SELECT, /* always select this thread first */
};
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c0efd80..2f57cf1c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -670,7 +670,6 @@ struct signal_struct {
atomic_t sigcnt;
atomic_t live;
int nr_threads;
- atomic_t oom_victims; /* # of TIF_MEDIE threads in this thread group */
struct list_head thread_head;
wait_queue_head_t wait_chldexit; /* for wait4() */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5043324..6afe1c5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1262,14 +1262,6 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
- case OOM_SCAN_ABORT:
- css_task_iter_end(&it);
- mem_cgroup_iter_break(memcg, iter);
- if (chosen)
- put_task_struct(chosen);
- /* Set a dummy value to return "true". */
- chosen = (void *) 1;
- goto unlock;
case OOM_SCAN_OK:
break;
};
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 223e1fe..b6b79ae 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -304,25 +304,6 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
return OOM_SCAN_CONTINUE;
/*
- * This task already has access to memory reserves and is being killed.
- * Don't allow any other task to have access to the reserves unless
- * the task has MMF_OOM_REAPED because chances that it would release
- * any memory is quite low.
- */
- if (!is_sysrq_oom(oc) && atomic_read(&task->signal->oom_victims)) {
- struct task_struct *p = find_lock_task_mm(task);
- enum oom_scan_t ret = OOM_SCAN_ABORT;
-
- if (p) {
- if (test_bit(MMF_OOM_REAPED, &p->mm->flags))
- ret = OOM_SCAN_CONTINUE;
- task_unlock(p);
- }
-
- return ret;
- }
-
- /*
* If task is allocating a lot of memory and has been marked to be
* killed first if it triggers an oom, then select it.
*/
@@ -354,9 +335,6 @@ static struct task_struct *select_bad_process(struct oom_control *oc,
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
- case OOM_SCAN_ABORT:
- rcu_read_unlock();
- return (struct task_struct *)(-1UL);
case OOM_SCAN_OK:
break;
};
@@ -626,7 +604,6 @@ void mark_oom_victim(struct task_struct *tsk)
/* OOM killer might race with memcg OOM */
if (test_and_set_tsk_thread_flag(tsk, TIF_MEMDIE))
return;
- atomic_inc(&tsk->signal->oom_victims);
/*
* Make sure that the task is woken up from uninterruptible sleep
* if it is frozen because OOM killer wouldn't be able to free
@@ -659,7 +636,6 @@ void exit_oom_victim(struct task_struct *tsk)
{
if (!test_and_clear_tsk_thread_flag(tsk, TIF_MEMDIE))
return;
- atomic_dec(&tsk->signal->oom_victims);
if (!atomic_dec_return(&oom_victims))
wake_up_all(&oom_victims_wait);
@@ -1012,7 +988,7 @@ bool out_of_memory(struct oom_control *oc)
dump_header(oc, NULL);
panic("Out of memory and no killable processes...\n");
}
- if (p && p != (void *)-1UL) {
+ if (p) {
oom_kill_process(oc, p, points, totalpages, "Out of memory");
/*
* Give the killed process a good chance to exit before trying
--
1.8.3.1
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