bool oom_killer_disabled __read_mostly;
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
#ifdef CONFIG_MMU
/*
* OOM Reaper kernel thread which tries to reap the memory used by the OOM
* victim (if that is possible) to help the OOM killer to move on.
*/
static struct task_struct *oom_reaper_th;
-static struct mm_struct *mm_to_reap;
static DECLARE_WAIT_QUEUE_HEAD(oom_reaper_wait);
+static struct task_struct *oom_reaper_list;
+static DEFINE_SPINLOCK(oom_reaper_lock);
+
-static bool __oom_reap_vmas(struct mm_struct *mm)
+static bool __oom_reap_task(struct task_struct *tsk)
{
struct mmu_gather tlb;
struct vm_area_struct *vma;
+ struct mm_struct *mm;
+ struct task_struct *p;
struct zap_details details = {.check_swap_entries = true,
.ignore_dirty = true};
bool ret = true;
- /* We might have raced with exit path */
- if (!atomic_inc_not_zero(&mm->mm_users))
+ /*
+ * Make sure we find the associated mm_struct even when the particular
+ * thread has already terminated and cleared its mm.
+ * We might have race with exit path so consider our work done if there
+ * is no mm.
+ */
+ p = find_lock_task_mm(tsk);
+ if (!p)
return true;
+ mm = p->mm;
+ if (!atomic_inc_not_zero(&mm->mm_users)) {
+ task_unlock(p);
+ return true;
+ }
+
+ task_unlock(p);
+
if (!down_read_trylock(&mm->mmap_sem)) {
ret = false;
goto out;
&details);
}
tlb_finish_mmu(&tlb, 0, -1);
+ pr_info("oom_reaper: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
+ task_pid_nr(tsk), tsk->comm,
+ K(get_mm_counter(mm, MM_ANONPAGES)),
+ K(get_mm_counter(mm, MM_FILEPAGES)),
+ K(get_mm_counter(mm, MM_SHMEMPAGES)));
up_read(&mm->mmap_sem);
+
+ /*
+ * Clear TIF_MEMDIE because the task shouldn't be sitting on a
+ * reasonably reclaimable memory anymore. OOM killer can continue
+ * by selecting other victim if unmapping hasn't led to any
+ * improvements. This also means that selecting this task doesn't
+ * make any sense.
+ */
+ tsk->signal->oom_score_adj = OOM_SCORE_ADJ_MIN;
+ exit_oom_victim(tsk);
out:
mmput(mm);
return ret;
}
-static void oom_reap_vmas(struct mm_struct *mm)
+#define MAX_OOM_REAP_RETRIES 10
+static void oom_reap_task(struct task_struct *tsk)
{
int attempts = 0;
/* Retry the down_read_trylock(mmap_sem) a few times */
- while (attempts++ < 10 && !__oom_reap_vmas(mm))
+ while (attempts++ < MAX_OOM_REAP_RETRIES && !__oom_reap_task(tsk))
schedule_timeout_idle(HZ/10);
+ if (attempts > MAX_OOM_REAP_RETRIES) {
+ pr_info("oom_reaper: unable to reap pid:%d (%s)\n",
+ task_pid_nr(tsk), tsk->comm);
+ debug_show_all_locks();
+ }
+
/* Drop a reference taken by wake_oom_reaper */
- mmdrop(mm);
+ put_task_struct(tsk);
}
static int oom_reaper(void *unused)
{
+ set_freezable();
+
while (true) {
- struct mm_struct *mm;
+ struct task_struct *tsk = NULL;
- wait_event_freezable(oom_reaper_wait,
- (mm = READ_ONCE(mm_to_reap)));
- oom_reap_vmas(mm);
- WRITE_ONCE(mm_to_reap, NULL);
+ wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL);
+ spin_lock(&oom_reaper_lock);
+ if (oom_reaper_list != NULL) {
+ tsk = oom_reaper_list;
+ oom_reaper_list = tsk->oom_reaper_list;
+ }
+ spin_unlock(&oom_reaper_lock);
+
+ if (tsk)
+ oom_reap_task(tsk);
}
return 0;
}
-static void wake_oom_reaper(struct mm_struct *mm)
+static void wake_oom_reaper(struct task_struct *tsk)
{
- struct mm_struct *old_mm;
-
if (!oom_reaper_th)
return;
- /*
- * Pin the given mm. Use mm_count instead of mm_users because
- * we do not want to delay the address space tear down.
- */
- atomic_inc(&mm->mm_count);
+ /* tsk is already queued? */
+ if (tsk == oom_reaper_list || tsk->oom_reaper_list)
+ return;
- /*
- * Make sure that only a single mm is ever queued for the reaper
- * because multiple are not necessary and the operation might be
- * disruptive so better reduce it to the bare minimum.
- */
- old_mm = cmpxchg(&mm_to_reap, NULL, mm);
- if (!old_mm)
- wake_up(&oom_reaper_wait);
- else
- mmdrop(mm);
+ get_task_struct(tsk);
+
+ spin_lock(&oom_reaper_lock);
+ tsk->oom_reaper_list = oom_reaper_list;
+ oom_reaper_list = tsk;
+ spin_unlock(&oom_reaper_lock);
+ wake_up(&oom_reaper_wait);
}
static int __init oom_init(void)
}
subsys_initcall(oom_init)
#else
-static void wake_oom_reaper(struct mm_struct *mm)
+static void wake_oom_reaper(struct task_struct *tsk)
{
}
#endif
/**
* exit_oom_victim - note the exit of an OOM victim
*/
-void exit_oom_victim(void)
+void exit_oom_victim(struct task_struct *tsk)
{
- clear_thread_flag(TIF_MEMDIE);
+ if (!test_and_clear_tsk_thread_flag(tsk, TIF_MEMDIE))
+ return;
if (!atomic_dec_return(&oom_victims))
wake_up_all(&oom_victims_wait);
return false;
}
-#define K(x) ((x) << (PAGE_SHIFT-10))
/*
* Must be called while holding a reference to p, which will be released upon
* returning.
rcu_read_unlock();
if (can_oom_reap)
- wake_oom_reaper(mm);
+ wake_oom_reaper(victim);
mmdrop(mm);
put_task_struct(victim);
projects / cascardo / linux.git / blobdiff