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From: David Howells <dhowells@redhat.com>
In-Reply-To: <20090622192453.GA6066@redhat.com>
References: <20090622192453.GA6066@redhat.com> <20090413214513.GA1119@redhat.com> <14878.1239876272@redhat.com> <20090416133658.GA6532@redhat.com> <20090416145444.GA12884@redhat.com> <20090618120716.fd1e4d92.akpm@linux-foundation.org> <20090618194238.GA17810@redhat.com> <20090622115148.5f1e5d1b.akpm@linux-foundation.org> <20090622171431.GA5010@redhat.com> <20090622140440.01d85542.akpm@linux-foundation.org> 
To: Oleg Nesterov <oleg@redhat.com>
Cc: dhowells@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
       jmorris@namei.org, roland@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rework/fix is_single_threaded()
Date: Thu, 09 Jul 2009 14:01:03 +0100
Message-ID: <28464.1247144463@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 754
Lines: 22

Oleg Nesterov <oleg@redhat.com> wrote:

> Unless David replies.

Sorry, I missed the last three messages.

> David, do you still dislike ->mmap_sem? I didn't see other objections,
> and again, imho tasklist_lock is worse.

My main objection to taking mmap_sem is that it restricts where the function
can be used.  It can't, for example, be called by anyone holding a spinlock.
Furthermore, the more locks, the more chance of someone accidentally
deadlocking something.

But apart from that, go for it.

David
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