Date: Fri, 23 Jan 2009 07:15:57 +0100
From: Andi Kleen <andi@firstfloor.org>
To: Matt Mackall <mpm@selenic.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Jonathan Corbet <corbet@lwn.net>, linux-kernel@vger.kernel.org,
       andi@firstfloor.org, viro@ZenIV.linux.org.uk, oleg@redhat.com,
       linux-api@vger.kernel.org, alan@lxorguk.ukuu.org.uk
Subject: Re: [PATCH, RFC] Remove fasync() BKL usage, take 3325
Message-ID: <20090123061557.GM15750@one.firstfloor.org>
References: <20090115153211.663df310@bike.lwn.net> <20090122065104.2787df2d.akpm@linux-foundation.org> <20090122221500.4c62aa54@tpl> <20090122213105.74142908.akpm@linux-foundation.org> <1232689549.5202.385.camel@calx>
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> I have to agree with Christoph. The priority here is breaking down the
> BKL and document all the things being protected by it and we've got a
> reasonably obvious patch in that direction. Meanwhile, there's not
> currently a pressing demand to make fasync in particular scale that I'm
> aware of.

The classic case is a high throughput network server that uses async
sockets. It has to call F_SETFL on each new socket it opens.

> Having a single big lock here is quite possibly something we'll want to
> fix down the road, agreed, but until we can actually measure it hurting
> us, debating about whether to use a bit lock or reuse an existing lock
> or add a new lock to all struct files is a bit premature.

I think i would agree with you if we didn't have a better patch
already, but if there's one it doesn't make sense not to use it.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.
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