From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 8 Sep 2006 10:24:59 +0100 (IST) From: Mel Gorman Subject: Re: [PATCH 0/8] Avoiding fragmentation with subzone groupings v25 In-Reply-To: <1157704232.17799.48.camel@lappy> Message-ID: References: <20060907190342.6166.49732.sendpatchset@skynet.skynet.ie> <20060907175848.63379fe1.akpm@osdl.org> <1157704232.17799.48.camel@lappy> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, 8 Sep 2006, Peter Zijlstra wrote: > On Thu, 2006-09-07 at 17:58 -0700, Andrew Morton wrote: >> On Thu, 7 Sep 2006 20:03:42 +0100 (IST) >> Mel Gorman wrote: >> >>> When a page is allocated, the page-flags >>> are updated with a value indicating it's type of reclaimability so that it >>> is placed on the correct list on free. >> >> We're getting awful tight on page-flags. >> >> Would it be possible to avoid adding the flag? Say, have a per-zone bitmap >> of size (zone->present_pages/(1<> there to work out whether a particular page is within a MAX_ORDER clump of >> easy-reclaimable pages? > > That would not actually work, the fallback allocation path can move > blocks smaller than MAX_ORDER to another recaim type. > Believe it or not, it may be desirably to have a whole block represented by one or two bits. If a fallback allocation occurs and I move blocks between lists, I want pages that free later to be freed to the new list as well. Currently that doesn't happen because the flags are set per-page but it used to happen in an early version of anti-frag. > But yeah, page flags are getting right, perhaps Rafael can use his > recently introduced bitmaps to rid us of the swsusp flags? > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org