path: root/mm
diff options
authorMichal Hocko <mhocko@kernel.org>2018-08-21 21:52:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 10:52:44 -0700
commit431f42fdfdb36f06f43c711fc59be9b814d8fb22 (patch)
tree6ea73077ff5b3f0abaef01179c3a832a86a6e2de /mm
parentc3b78b11efbb2865433abf9d22c004ffe4a73f5c (diff)
mm/oom_kill.c: clean up oom_reap_task_mm()
Andrew has noticed some inconsistencies in oom_reap_task_mm. Notably - Undocumented return value. - comment "failed to reap part..." is misleading - sounds like it's referring to something which happened in the past, is in fact referring to something which might happen in the future. - fails to call trace_finish_task_reaping() in one case - code duplication. - Increases mmap_sem hold time a little by moving trace_finish_task_reaping() inside the locked region. So sue me ;) - Sharing the finish: path means that the trace event won't distinguish between the two sources of finishing. Add a short explanation for the return value and fix the rest by reorganizing the function a bit to have unified function exit paths. Link: http://lkml.kernel.org/r/20180724141747.GP28386@dhcp22.suse.cz Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
1 files changed, 16 insertions, 8 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ed5e6a221a8e..20600779f5db 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -534,8 +534,16 @@ bool __oom_reap_task_mm(struct mm_struct *mm)
return ret;
+ * Reaps the address space of the give task.
+ *
+ * Returns true on success and false if none or part of the address space
+ * has been reclaimed and the caller should retry later.
+ */
static bool oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
+ bool ret = true;
if (!down_read_trylock(&mm->mmap_sem)) {
return false;
@@ -548,28 +556,28 @@ static bool oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
* down_write();up_write() cycle in exit_mmap().
if (test_bit(MMF_OOM_SKIP, &mm->flags)) {
- up_read(&mm->mmap_sem);
- return true;
+ goto out_unlock;
/* failed to reap part of the address space. Try again later */
- if (!__oom_reap_task_mm(mm)) {
- up_read(&mm->mmap_sem);
- return false;
- }
+ ret = __oom_reap_task_mm(mm);
+ if (!ret)
+ goto out_finish;
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)));
+ trace_finish_task_reaping(tsk->pid);
- trace_finish_task_reaping(tsk->pid);
- return true;
+ return ret;