Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761622AbZD1SgU (ORCPT ); Tue, 28 Apr 2009 14:36:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753505AbZD1SgH (ORCPT ); Tue, 28 Apr 2009 14:36:07 -0400 Received: from gir.skynet.ie ([193.1.99.77]:35573 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751633AbZD1SgF (ORCPT ); Tue, 28 Apr 2009 14:36:05 -0400 Date: Tue, 28 Apr 2009 19:36:01 +0100 From: Mel Gorman To: Hugh Dickins Cc: Christoph Lameter , Andrew Morton , Linux Memory Management List , KOSAKI Motohiro , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Peter Zijlstra , Pekka Enberg , "Zhang, Yanmin" Subject: Re: [PATCH] Properly account for freed pages in free_pages_bulk() and when allocating high-order pages in buffered_rmqueue() Message-ID: <20090428183601.GC18893@csn.ul.ie> References: <1240408407-21848-1-git-send-email-mel@csn.ul.ie> <1240819119.2567.884.camel@ymzhang> <20090427143845.GC912@csn.ul.ie> <1240883957.2567.886.camel@ymzhang> <20090428103159.GB23540@csn.ul.ie> <20090428165129.GA18893@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1974 Lines: 47 On Tue, Apr 28, 2009 at 06:15:30PM +0100, Hugh Dickins wrote: > On Tue, 28 Apr 2009, Mel Gorman wrote: > > On Tue, Apr 28, 2009 at 12:37:22PM -0400, Christoph Lameter wrote: > > > On Tue, 28 Apr 2009, Mel Gorman wrote: > > > > > > > @@ -1151,6 +1151,7 @@ again: > > > > } else { > > > > spin_lock_irqsave(&zone->lock, flags); > > > > page = __rmqueue(zone, order, migratetype); > > > > + __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order)); > > > > spin_unlock(&zone->lock); > > > > if (!page) > > > > goto failed; > > > > > > __mod_zone_page_state takes an signed integer argument. Not sure what is > > > won by the UL suffix here. > > > > > > > Matches other call sites such as in __offline_isolated_pages(), habit when > > using shifts like this and matches other locations, paranoia, doesn't hurt. > > Well, not a big deal, but I'd say that it does hurt: by wasting people's > time (mine!), wondering what that "UL" is for - I'd have had to ask, if > Christoph hadn't cleared this up first (thank you). And elsewhere, > you're using an int << order to update NR_FREE_PAGES, so I don't see > the consistency argument. > Ok, I'll concede things are not super-consistent. In this case, I felt it "didn't hurt" but I didn't take into account that it needs to be worked out each time and I posted a second revision that should be clearer. As an aside, in other places order changes from being signed in some places to being unsigned in others. There is probably a pass in there just for dealing with this sort of inconsistency. Thanks -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/