* [PATCH] proc_oom_score: remove tasklist_lock and pid_alive()
@ 2016-06-08 21:19 Oleg Nesterov
2016-06-08 22:48 ` David Rientjes
2016-06-09 6:44 ` Michal Hocko
0 siblings, 2 replies; 3+ messages in thread
From: Oleg Nesterov @ 2016-06-08 21:19 UTC (permalink / raw)
To: Andrew Morton; +Cc: David Rientjes, Michal Hocko, Tetsuo Handa, linux-kernel
This was needed before to ensure that ->signal != 0 and do_each_thread()
is safe, see the commit b95c35e76b29b for details.
Today tsk->signal can't go away and for_each_thread(tsk) is always safe.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
fs/proc/base.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a11eb71..93e7754 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -579,11 +579,8 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
unsigned long totalpages = totalram_pages + total_swap_pages;
unsigned long points = 0;
- read_lock(&tasklist_lock);
- if (pid_alive(task))
- points = oom_badness(task, NULL, NULL, totalpages) *
- 1000 / totalpages;
- read_unlock(&tasklist_lock);
+ points = oom_badness(task, NULL, NULL, totalpages) *
+ 1000 / totalpages;
seq_printf(m, "%lu\n", points);
return 0;
--
2.5.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] proc_oom_score: remove tasklist_lock and pid_alive()
2016-06-08 21:19 [PATCH] proc_oom_score: remove tasklist_lock and pid_alive() Oleg Nesterov
@ 2016-06-08 22:48 ` David Rientjes
2016-06-09 6:44 ` Michal Hocko
1 sibling, 0 replies; 3+ messages in thread
From: David Rientjes @ 2016-06-08 22:48 UTC (permalink / raw)
To: Oleg Nesterov; +Cc: Andrew Morton, Michal Hocko, Tetsuo Handa, linux-kernel
On Wed, 8 Jun 2016, Oleg Nesterov wrote:
> This was needed before to ensure that ->signal != 0 and do_each_thread()
> is safe, see the commit b95c35e76b29b for details.
>
> Today tsk->signal can't go away and for_each_thread(tsk) is always safe.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] proc_oom_score: remove tasklist_lock and pid_alive()
2016-06-08 21:19 [PATCH] proc_oom_score: remove tasklist_lock and pid_alive() Oleg Nesterov
2016-06-08 22:48 ` David Rientjes
@ 2016-06-09 6:44 ` Michal Hocko
1 sibling, 0 replies; 3+ messages in thread
From: Michal Hocko @ 2016-06-09 6:44 UTC (permalink / raw)
To: Oleg Nesterov; +Cc: Andrew Morton, David Rientjes, Tetsuo Handa, linux-kernel
On Wed 08-06-16 23:19:21, Oleg Nesterov wrote:
> This was needed before to ensure that ->signal != 0 and do_each_thread()
> is safe, see the commit b95c35e76b29b for details.
>
> Today tsk->signal can't go away and for_each_thread(tsk) is always safe.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> fs/proc/base.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index a11eb71..93e7754 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -579,11 +579,8 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
> unsigned long totalpages = totalram_pages + total_swap_pages;
> unsigned long points = 0;
>
> - read_lock(&tasklist_lock);
> - if (pid_alive(task))
> - points = oom_badness(task, NULL, NULL, totalpages) *
> - 1000 / totalpages;
> - read_unlock(&tasklist_lock);
> + points = oom_badness(task, NULL, NULL, totalpages) *
> + 1000 / totalpages;
> seq_printf(m, "%lu\n", points);
>
> return 0;
> --
> 2.5.0
>
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-06-08 21:19 [PATCH] proc_oom_score: remove tasklist_lock and pid_alive() Oleg Nesterov
2016-06-08 22:48 ` David Rientjes
2016-06-09 6:44 ` Michal Hocko
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