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Date: Thu, 17 May 2007 06:00:46 +0100
From: Al Viro <viro@ftp.linux.org.uk>
To: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Convert namespace_sem to a mutex
Message-ID: <20070517050046.GM4095@ftp.linux.org.uk>
References: <20070517045041.GA4462@in.ibm.com>
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On Thu, May 17, 2007 at 10:20:41AM +0530, Bharata B Rao 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
> 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
> for this sem, this can be a generic sem (and not rwsem) and if so it can be
> a mutex.

Except that read accesses outnumber write ones by far and we have no reason
for serializing them against each other.  NAK.
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