From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: Is nobh code still useful? Date: Fri, 18 Sep 2009 16:25:54 +0200 Message-ID: <20090918162554.13a72664@infradead.org> References: <20090917135627.GB13660@duck.suse.cz> <4AB30AD1.7010400@us.ibm.com> <20090918141226.GB26991@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Badari Pulavarty , Jan Kara , linux-fsdevel@vger.kernel.org, LKML , Andrew Morton To: Theodore Tso Return-path: Received: from casper.infradead.org ([85.118.1.10]:35011 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751794AbZIROZ7 (ORCPT ); Fri, 18 Sep 2009 10:25:59 -0400 In-Reply-To: <20090918141226.GB26991@mit.edu> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, 18 Sep 2009 10:12:26 -0400 Theodore Tso wrote: > On Thu, Sep 17, 2009 at 09:21:37PM -0700, Badari Pulavarty wrote: > > > > Originally it was supported on ext2. I added support nobh support > > for ext3. At that time, the main > > issue/complaint was that, these bufferheads consume memory from > > ZONE_NORMAL causing > > memory pressure on 32-bit (i386) configurations. > > Specifically, it matters on very large configuration systems (i.e., > 32GB-64GB using PAE-36) that today we'd probably just say, "use > x86_64, you moron". It would probably matter if someone were to want > to upgrade a non-64-bit capable machine to a newer kernel. > > Dropping nobh from ext3 at this point might prevent some of these > older systems from upgrading, I'm not sure how much we would care; on > the one hand, these machines tended to be pretty expensive, so people > would probably want to use them for a while. On the other hand, it > has been over five years now since x86_64 machines have been > available, and many of these customers are highly unlikely to want to > upgrade anyway. isn't the converse to just make nobh the default but not an option a better approach then? I forgot why this was a good idea to be an option again ;-) -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org