From: Rik van Riel <riel@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>, Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Frank Mayhar <fmayhar@google.com>,
Frederic Weisbecker <fweisbec@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Sanjay Rao <srao@redhat.com>, Larry Woodman <lwoodman@redhat.com>
Subject: Re: [PATCH RFC] time: drop do_sys_times spinlock
Date: Wed, 13 Aug 2014 13:50:24 -0400 [thread overview]
Message-ID: <53EBA560.8030404@redhat.com> (raw)
In-Reply-To: <20140813174048.GV9918@twins.programming.kicks-ass.net>
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On 08/13/2014 01:40 PM, Peter Zijlstra wrote:
> So the problem with the above is the lack of fwd progress; if
> there's enough clone()/exit() happening in the thread group (and
> the more CPUs the more possible), we'll keep repeating.
We can fall back to taking the lock if we circle around,
or if there is a writer active when we are in seqcount_read,
similar to what the semaphore (ipc/sem.c) code is doing.
read_seqbegin_or_lock would do the trick...
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next prev parent reply other threads:[~2014-08-13 17:52 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-12 18:25 [PATCH RFC] time: drop do_sys_times spinlock Rik van Riel
2014-08-12 19:12 ` Oleg Nesterov
2014-08-12 19:22 ` Rik van Riel
2014-08-12 22:27 ` Rik van Riel
2014-08-13 17:22 ` Oleg Nesterov
2014-08-13 17:35 ` Rik van Riel
2014-08-13 18:08 ` Oleg Nesterov
2014-08-13 18:25 ` Rik van Riel
2014-08-13 18:45 ` Oleg Nesterov
2014-08-13 18:57 ` Rik van Riel
2014-08-13 21:03 ` [PATCH RFC] time,signal: protect resource use statistics with seqlock Rik van Riel
2014-08-14 0:43 ` Frederic Weisbecker
2014-08-14 1:57 ` Rik van Riel
2014-08-14 13:34 ` Frederic Weisbecker
2014-08-14 14:39 ` Oleg Nesterov
2014-08-15 2:52 ` Frederic Weisbecker
2014-08-15 14:26 ` Oleg Nesterov
2014-08-15 22:33 ` Frederic Weisbecker
2014-08-14 13:22 ` Oleg Nesterov
2014-08-14 13:38 ` Frederic Weisbecker
2014-08-14 13:53 ` Oleg Nesterov
2014-08-14 17:48 ` Oleg Nesterov
2014-08-14 18:34 ` Oleg Nesterov
2014-08-15 5:19 ` Mike Galbraith
2014-08-15 6:28 ` Peter Zijlstra
2014-08-15 9:37 ` Mike Galbraith
2014-08-15 9:44 ` Peter Zijlstra
2014-08-15 16:36 ` Oleg Nesterov
2014-08-15 16:49 ` Oleg Nesterov
2014-08-15 17:25 ` Rik van Riel
2014-08-15 18:36 ` Oleg Nesterov
2014-08-14 14:24 ` Oleg Nesterov
2014-08-14 15:37 ` Rik van Riel
2014-08-14 16:12 ` Oleg Nesterov
2014-08-14 17:36 ` Rik van Riel
2014-08-14 18:15 ` Oleg Nesterov
2014-08-14 19:03 ` Rik van Riel
2014-08-14 19:37 ` Oleg Nesterov
2014-08-15 2:14 ` Rik van Riel
2014-08-15 14:58 ` Oleg Nesterov
2014-08-13 21:03 ` Rik van Riel
2014-08-13 17:40 ` [PATCH RFC] time: drop do_sys_times spinlock Peter Zijlstra
2014-08-13 17:50 ` Rik van Riel [this message]
2014-08-13 17:53 ` Peter Zijlstra
2014-08-13 6:59 ` Mike Galbraith
2014-08-13 11:11 ` Peter Zijlstra
2014-08-13 13:24 ` Rik van Riel
2014-08-13 13:39 ` Peter Zijlstra
2014-08-13 14:09 ` Mike Galbraith
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