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From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
	Michal Hocko <mhocko@kernel.org>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	linux-kernel@vger.kernel.org
Subject: [PATCH] proc_oom_score: remove tasklist_lock and pid_alive()
Date: Wed, 8 Jun 2016 23:19:21 +0200	[thread overview]
Message-ID: <20160608211921.GA15508@redhat.com> (raw)

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

             reply	other threads:[~2016-06-08 21:19 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-08 21:19 Oleg Nesterov [this message]
2016-06-08 22:48 ` David Rientjes
2016-06-09  6:44 ` Michal Hocko

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