diff options
| -rw-r--r-- | mm/oom_kill.c | 45 |
1 files changed, 23 insertions, 22 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 9a643c4bf77..042e6436c3e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -254,17 +254,24 @@ static void __oom_kill_task(task_t *p, const char *message) force_sig(SIGKILL, p); } -static struct mm_struct *oom_kill_task(task_t *p, const char *message) +static int oom_kill_task(task_t *p, const char *message) { - struct mm_struct *mm = get_task_mm(p); + struct mm_struct *mm; task_t * g, * q; - if (!mm) - return NULL; - if (mm == &init_mm) { - mmput(mm); - return NULL; - } + mm = p->mm; + + /* WARNING: mm may not be dereferenced since we did not obtain its + * value from get_task_mm(p). This is OK since all we need to do is + * compare mm to q->mm below. + * + * Furthermore, even if mm contains a non-NULL value, p->mm may + * change to NULL at any time since we do not hold task_lock(p). + * However, this is of no concern to us. + */ + + if (mm == NULL || mm == &init_mm) + return 1; __oom_kill_task(p, message); /* @@ -276,13 +283,12 @@ static struct mm_struct *oom_kill_task(task_t *p, const char *message) __oom_kill_task(q, message); while_each_thread(g, q); - return mm; + return 0; } -static struct mm_struct *oom_kill_process(struct task_struct *p, - unsigned long points, const char *message) +static int oom_kill_process(struct task_struct *p, unsigned long points, + const char *message) { - struct mm_struct *mm; struct task_struct *c; struct list_head *tsk; @@ -293,9 +299,8 @@ static struct mm_struct *oom_kill_process(struct task_struct *p, c = list_entry(tsk, struct task_struct, sibling); if (c->mm == p->mm) continue; - mm = oom_kill_task(c, message); - if (mm) - return mm; + if (!oom_kill_task(c, message)) + return 0; } return oom_kill_task(p, message); } @@ -310,7 +315,6 @@ static struct mm_struct *oom_kill_process(struct task_struct *p, */ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) { - struct mm_struct *mm = NULL; task_t *p; unsigned long points = 0; @@ -330,12 +334,12 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) */ switch (constrained_alloc(zonelist, gfp_mask)) { case CONSTRAINT_MEMORY_POLICY: - mm = oom_kill_process(current, points, + oom_kill_process(current, points, "No available memory (MPOL_BIND)"); break; case CONSTRAINT_CPUSET: - mm = oom_kill_process(current, points, + oom_kill_process(current, points, "No available memory in cpuset"); break; @@ -357,8 +361,7 @@ retry: panic("Out of memory and no killable processes...\n"); } - mm = oom_kill_process(p, points, "Out of memory"); - if (!mm) + if (oom_kill_process(p, points, "Out of memory")) goto retry; break; @@ -367,8 +370,6 @@ retry: out: read_unlock(&tasklist_lock); cpuset_unlock(); - if (mm) - mmput(mm); /* * Give "p" a good chance of killing itself before we |