From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Subject: Re: [PATCH] ns: move free_nsproxy() out of do_exit() path
Date: Fri, 13 Jul 2012 14:08:06 -0700
Message-ID: <20120713140806.b3d0fda8.akpm@linux-foundation.org>
References: <1342180088-22647-1-git-send-email-kirill.shutemov@linux.intel.com>
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To: "Kirill A. Shutemov" <kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
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On Fri, 13 Jul 2012 14:48:08 +0300
"Kirill A. Shutemov" <kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> wrote:

> From: "Kirill A. Shutemov" <kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> 
> free_nsproxy() is too heavy to be on exit path. Let's free namespaces
> asynchronously to not block exit_group() syscall.

Please be specific, and complete.

Why is it "too heavy"?  Where is the time being spent?  Is it spent in
D state or is it spent burning CPU cycles?  Does the patch simply
offload the work into kernel threads, providing no net gain?

> The patch also fixes bug with free namespace without synchronize_rcu() through
> put_nsproxy().

I just don't understand this description.  Please send a new one which
includes all details about the bug, including a description of
the user-visible effects of the bug.