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Date: Thu, 17 May 2007 10:30:29 +0530
From: "Satyam Sharma" <satyam.sharma@gmail.com>
To: bharata@linux.vnet.ibm.com
Subject: Re: Convert namespace_sem to a mutex
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <20070517045041.GA4462@in.ibm.com>
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On 5/17/07, Bharata B Rao <bharata@linux.vnet.ibm.com> wrote:
> From: Bharata B Rao <bharata@linux.vnet.ibm.com>
>
> namespace_sem is a rwsem. It is acquired as read sem at only one place(used
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Actually, this ...

> by /proc/mounts, /proc/<pid>/mounts and /proc/<pid>/mountstats). In all other
> cases it is acquired as a write sem. So, as there is not more than one reader
                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

... does not mean this. Multiple threads could be reading mounts or
mountstats, and otoh mount(2) and umount(2) (acquire it as write sem)
could be less frequent?

> for this sem, this can be a generic sem (and not rwsem) and if so it can be
> a mutex.
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