diff options
| author | Michal Hocko <mhocko@kernel.org> | 2018-08-22 06:52:45 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-22 19:52:44 +0200 |
| commit | 431f42fdfdb36f06f43c711fc59be9b814d8fb22 (patch) | |
| tree | 6ea73077ff5b3f0abaef01179c3a832a86a6e2de /mm/oom_kill.c | |
| parent | mm, oom: describe task memory unit, larger PID pad (diff) | |
| download | linux-431f42fdfdb36f06f43c711fc59be9b814d8fb22.tar.xz linux-431f42fdfdb36f06f43c711fc59be9b814d8fb22.zip | |
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/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 24 |
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)) { trace_skip_task_reaping(tsk->pid); 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); trace_skip_task_reaping(tsk->pid); - return true; + goto out_unlock; } trace_start_task_reaping(tsk->pid); /* 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))); +out_finish: + trace_finish_task_reaping(tsk->pid); +out_unlock: up_read(&mm->mmap_sem); - trace_finish_task_reaping(tsk->pid); - return true; + return ret; } #define MAX_OOM_REAP_RETRIES 10 |