From: Andrew Morton Subject: Re: booked-page-flag.patch Date: Thu, 15 Feb 2007 12:56:54 -0800 Message-ID: <20070215125654.b0f18ab3.akpm@linux-foundation.org> References: <20070215004504.023a90f0.akpm@linux-foundation.org> <45D495EA.3060200@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Eric Sandeen , "Theodore Ts'o" , "linux-ext4@vger.kernel.org" To: Alex Tomas Return-path: Received: from smtp.osdl.org ([65.172.181.24]:33796 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161250AbXBOU5h (ORCPT ); Thu, 15 Feb 2007 15:57:37 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, 15 Feb 2007 20:30:43 +0300 Alex Tomas wrote: > >>>>> Eric Sandeen (ES) writes: > > ES> Andrew Morton wrote: > >> Sorry, we're seriously, seriously, seriously short on flags in the page > >> struct and this patch is going to need one heck of a good case for it to be > >> acceptable. > > ES> This was for the delayed allocation patchset, right; and by managing > ES> this at the page level that means we can't do this for block size < > ES> page size, I think... > > I still think that having PG_booked and special code to handle > case when blocksize==pagesize is worthwhile -- we save 56 bytes > on 32bit and 104 bytes on 64bit for every written page. > If the page doesn't have buffer-heads, set PG_private and clear page->private If the page does have buffer_heads, use BH_Delay.