From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1764625AbYD0XlU@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1764625AbYD0XlU (ORCPT <rfc822;w@1wt.eu>);
	Sun, 27 Apr 2008 19:41:20 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758620AbYD0XlM
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Sun, 27 Apr 2008 19:41:12 -0400
Received: from relay2.sgi.com ([192.48.171.30]:46991 "EHLO relay.sgi.com"
	rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP
	id S1753120AbYD0XlM (ORCPT
	<rfc822;@relay.sgi.com:linux-kernel@vger.kernel.org>);
	Sun, 27 Apr 2008 19:41:12 -0400
Date: Mon, 28 Apr 2008 09:40:56 +1000
From: David Chinner <dgc@sgi.com>
To: Denys Vlasenko <vda.linux@googlemail.com>
Cc: David Chinner <dgc@sgi.com>, xfs@oss.sgi.com,
       Eric Sandeen <sandeen@sandeen.net>, Adrian Bunk <bunk@kernel.org>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] xfs: reduce stack usage in xfs_bmap_btalloc()
Message-ID: <20080427234056.GA108924158@sgi.com>
References: <200804261651.02078.vda.linux@googlemail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200804261651.02078.vda.linux@googlemail.com>
User-Agent: Mutt/1.4.2.1i
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, Apr 26, 2008 at 04:51:02PM +0200, Denys Vlasenko wrote:
> Hi David,
> 
> This patch reduces xfs_bmap_btalloc() stack usage by 50 bytes
> by moving part of its body into a helper function.

Can you please attach your patches inline, Denys (see
Documentation/SubmittingPatches)?

> This results in some variables not taking stack space in
> xfs_bmap_btalloc() anymore.
> 
> The helper itself does not call anything stack-deep.
> Stack-deep call to xfs_alloc_vextent() happen
> in xfs_bmap_btalloc(), as before.

I have a set of patches that introduces new functionality into the
allocator (dynamic allocation policies) that reduces
xfs_bmap_btalloc() function by 36 bytes (just by chance, I didn't
design it for this purpose). It breaks it down on functional
boundaries like Christoph's patch. I'm going to revist that patch
w.r.t both these patches and see what falls out the bottom...

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group