Re: [PATCH] ns: move free_nsproxy() out of do_exit() path

From: Andrew Morton
Date: Fri Jul 13 2012 - 17:08:03 EST


On Fri, 13 Jul 2012 14:48:08 +0300
"Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:

> From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
>
> 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.

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