From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>,
Americo Wang <xiyou.wangcong@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Roland McGrath <roland@redhat.com>,
Spencer Candland <spencer@bluehost.com>,
Stanislaw Gruszka <sgruszka@redhat.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH -mm 0/4] cputimers/proc: do_task_stat: don't walk through the thread list under ->siglock
Date: Mon, 29 Mar 2010 20:12:04 +0200 [thread overview]
Message-ID: <20100329181204.GA16356@redhat.com> (raw)
In-Reply-To: <20100329125415.GA22451@redhat.com>
On 03/29, Oleg Nesterov wrote:
>
> Yes sure. I dislike the do_task_stat() case because we always do this,
> even if this info is not needed, say, for /bin/ps.
Note also that nobody else in /fs/proc needs ->siglock. Except
do_io_accounting(), but in this case the user-space explicitly asks for
this info.
OK, This is V2. Still RFC, although I think 1/4 makes sense in any case.
Please comment. Again, I am more or less sure these changes are "correct",
but I don't know what /bin/top can think ;)
I don't really like the fact thread_group_times() takes cputimer.lock,
but imho lock_task_sighand() in do_task_stat() is much worse.
Oleg.
next prev parent reply other threads:[~2010-03-29 18:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-24 20:45 [RFC,PATCH 1/2] cputimers/proc: do_task_stat()->task_times() can race with getrusage() Oleg Nesterov
2010-03-26 3:53 ` Balbir Singh
2010-03-26 7:37 ` Stanislaw Gruszka
2010-03-26 16:12 ` Stanislaw Gruszka
2010-03-26 21:49 ` Oleg Nesterov
2010-03-29 11:17 ` Stanislaw Gruszka
2010-03-29 12:54 ` Oleg Nesterov
2010-03-29 18:12 ` Oleg Nesterov [this message]
2010-03-29 18:12 ` [PATCH -mm 1/4] cputimers: thread_group_cputime: cleanup rcu/signal stuff Oleg Nesterov
2010-03-29 18:13 ` [PATCH -mm 2/4] cputimers: make sure thread_group_cputime() can't count the same thread twice lockless Oleg Nesterov
2010-03-30 11:01 ` Stanislaw Gruszka
2010-03-30 13:43 ` Oleg Nesterov
2010-03-29 18:13 ` [PATCH -mm 3/4] cputimers: thread_group_times: make it rcu-safe Oleg Nesterov
2010-03-29 18:14 ` [PATCH -mm 1/4] cputimers: do_task_stat: avoid ->siglock for while_each_thread() Oleg Nesterov
2010-03-29 18:16 ` Oleg Nesterov
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