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From: Roland McGrath <roland@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
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Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 1/2] oom: don't ignore rss in nascent mm
In-Reply-To: Oleg Nesterov's message of  Friday, 10 September 2010 00:05:04 +0200 <20100909220504.GA6273@redhat.com>
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X-Windows: putting new limits on productivity.
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Date: Fri, 10 Sep 2010 02:39:58 -0700 (PDT)
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> I wonder if it makes sense to move ->cred_guard_mutex from task_struct
> to signal_struct and thus make multiple-threads-inside-exec impossible.
> Only one thread can win anyway.

That probably makes sense.  Note that cred_guard_mutex is also overloaded
for ptrace_attach, so this would add some more serialization of attaches to
threads in the same group.  But as long as actual attachment serializes on
tasklist_lock anyway, it doesn't make a material difference.  (Even without
that, it would presumably be the same debugger attaching serially to
threads in the same group, so it wouldn't degrade anything in practice.)


Thanks,
Roland