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From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Michal Hocko <mhocko@kernel.org>,
	adobriyan@gmail.com, willy@infradead.org, mguzik@redhat.com,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [v2 PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct
Date: Tue, 27 Mar 2018 21:52:17 +0300	[thread overview]
Message-ID: <20180327185217.GK2236@uranus> (raw)
In-Reply-To: <95a107ac-5e5b-92d7-dbde-2e961d85de28@linux.alibaba.com>

On Tue, Mar 27, 2018 at 02:38:11PM -0400, Yang Shi wrote:
> > Why do we need to hold mmap_sem here and call find_vma, when only
> > PR_SET_MM_ENV_END: is consuming it? I guess we can replace it wit the
> > new lock and take the mmap_sem only for PR_SET_MM_ENV_END.
> 
> Actually, I didn't think of why. It looks prctl_set_mm() checks if vma does
> exist when it tries to set stack_start, argv_* and env_*, btw not only
> env_end.
> 
> Cyrill may be able to give us some hint since C/R is the main user of this
> API.

First and most important it makes code smaller. This prctl call is really
rarely used. Of course we can optimize it, but as I said I would prefer
to simply deprecate this old interface (and I gonne to do so once time
permit).

  reply	other threads:[~2018-03-27 18:52 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-26 18:20 [v2 PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct Yang Shi
2018-03-26 18:37 ` Matthew Wilcox
2018-03-26 19:21   ` Cyrill Gorcunov
2018-03-26 21:10     ` Tetsuo Handa
2018-03-26 21:20       ` Yang Shi
2018-03-26 21:29       ` Cyrill Gorcunov
2018-03-26 22:00         ` Tetsuo Handa
2018-03-26 22:12           ` Yang Shi
2018-03-27  7:38             ` Cyrill Gorcunov
2018-03-27  7:37           ` Cyrill Gorcunov
2018-03-26 21:59     ` Yang Shi
2018-03-27  7:32       ` Cyrill Gorcunov
2018-03-27 18:44         ` Yang Shi
2018-03-26 19:42 ` Mateusz Guzik
2018-03-26 21:10   ` Yang Shi
2018-03-27  6:29 ` Michal Hocko
2018-03-27 14:31   ` Mateusz Guzik
2018-03-27 14:43     ` Michal Hocko
2018-03-27 18:38   ` Yang Shi
2018-03-27 18:52     ` Cyrill Gorcunov [this message]
2018-03-28 13:10       ` Michal Hocko
2018-04-02  1:58   ` Yang Shi

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