From: Andrew Morton <akpm@osdl.org>
To: Paul Jackson <pj@sgi.com>
Cc: kamezawa.hiroyu@jp.fujitsu.com, linux-kernel@vger.kernel.org,
ebiederm@xmission.com
Subject: Re: [RFC] ps command race fix
Date: Mon, 24 Jul 2006 19:00:30 -0700 [thread overview]
Message-ID: <20060724190030.34884a67.akpm@osdl.org> (raw)
In-Reply-To: <20060724184847.3ff6be7d.pj@sgi.com>
On Mon, 24 Jul 2006 18:48:47 -0700
Paul Jackson <pj@sgi.com> wrote:
> Another possibility (perhaps a really stupid idea ;) would be to
> snapshot the list of pids on the open, and let the readdir() just
> access that fixed array.
The patch under discussion does precisely this. (Awkwardly. Using
kmalloc-pre-object might be better).
> The kernel/cpuset.c cpuset_tasks_open() routine that displays the
> pids of tasks in a cpuset (the per-cpuset 'tasks' file) does this.
Your faith in large kmalloc()s is touching ;) I guess the number of pids
will be smaller for cpusets.
> Then the seek and read and such semantics are nice and stable and
> simple.
>
> Throw out the snapshot on the last close.
The patch under discussion didn't do this, although it could. But it still
permits rather a lot of kernel memory to be pinned.
next prev parent reply other threads:[~2006-07-25 2:00 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-14 11:39 [RFC] ps command race fix KAMEZAWA Hiroyuki
2006-07-25 1:20 ` Andrew Morton
2006-07-25 1:48 ` Paul Jackson
2006-07-25 2:00 ` Andrew Morton [this message]
2006-07-25 2:08 ` KAMEZAWA Hiroyuki
2006-07-25 2:33 ` Andrew Morton
2006-07-25 2:50 ` KAMEZAWA Hiroyuki
2006-07-25 3:16 ` KAMEZAWA Hiroyuki
2006-08-13 16:29 ` Eric W. Biederman
2006-08-13 17:34 ` Andrew Morton
2006-08-13 19:00 ` Eric W. Biederman
2006-08-13 19:12 ` Paul Jackson
2006-08-16 1:23 ` KAMEZAWA Hiroyuki
2006-08-17 4:59 ` Eric W. Biederman
2006-08-17 6:32 ` KAMEZAWA Hiroyuki
2006-08-17 13:39 ` Eric W. Biederman
2006-08-17 18:16 ` Jean Delvare
2006-08-18 0:21 ` KAMEZAWA Hiroyuki
2006-08-18 3:53 ` Eric W. Biederman
2006-08-13 20:08 ` Albert Cahalan
2006-08-16 2:20 ` Kyle Moffett
2006-07-25 7:22 ` Paul Jackson
2006-07-25 1:53 ` KAMEZAWA Hiroyuki
2006-07-25 2:06 ` Andrew Morton
2006-07-25 2:34 ` KAMEZAWA Hiroyuki
2006-07-25 6:09 ` Eric W. Biederman
-- strict thread matches above, loose matches on Subject: below --
2006-07-25 6:47 Albert Cahalan
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