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From: Michal Hocko <mhocko@kernel.org>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>,
	adobriyan@gmail.com, willy@infradead.org, mguzik@redhat.com,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [v3 PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct
Date: Tue, 10 Apr 2018 12:42:15 +0200	[thread overview]
Message-ID: <20180410104215.GB21835@dhcp22.suse.cz> (raw)
In-Reply-To: <20180410094047.GB2041@uranus.lan>

On Tue 10-04-18 12:40:47, Cyrill Gorcunov wrote:
> On Tue, Apr 10, 2018 at 11:09:17AM +0200, Michal Hocko wrote:
> > On Tue 10-04-18 05:52:54, Yang Shi wrote:
> > [...]
> > > So, introduce a new spinlock in mm_struct to protect the concurrent
> > > access to arg_start|end, env_start|end and others except start_brk and
> > > brk, which are still protected by mmap_sem to avoid concurrent access
> > > from do_brk().
> > 
> > Is there any fundamental problem with brk using the same lock?
> 
> Seems so. Look into mm/mmap.c:brk syscall which reads and writes
> brk value under mmap_sem ('cause of do_brk called inside).

Why cannot we simply use the lock when the value is updated?

-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2018-04-10 10:42 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-09 21:52 [v3 PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct Yang Shi
2018-04-10  8:48 ` Cyrill Gorcunov
2018-04-10  9:09 ` Michal Hocko
2018-04-10  9:40   ` Cyrill Gorcunov
2018-04-10 10:42     ` Michal Hocko [this message]
2018-04-10 11:02       ` Cyrill Gorcunov
2018-04-10 11:10         ` Michal Hocko
2018-04-10 12:28           ` Cyrill Gorcunov
2018-04-10 16:21             ` Yang Shi
2018-04-10 18:28               ` Yang Shi
2018-04-10 19:17                 ` Cyrill Gorcunov
2018-04-10 19:33                   ` Yang Shi
2018-04-10 20:06                     ` Cyrill Gorcunov
2018-04-12 12:18                 ` Michal Hocko
2018-04-12 16:20                   ` Yang Shi
2018-04-13  6:56                     ` Michal Hocko

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