From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id AA4E36B0068 for ; Tue, 19 Jun 2012 12:26:53 -0400 (EDT) Date: Tue, 19 Jun 2012 17:26:43 +0100 From: Mel Gorman Subject: Re: [PATCH] cma: cached pageblock type fixup Message-ID: <20120619162643.GC8810@suse.de> References: <201205230922.00530.b.zolnierkie@samsung.com> <201206191328.50781.b.zolnierkie@samsung.com> <20120619120044.GA8810@suse.de> <201206191504.59994.b.zolnierkie@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <201206191504.59994.b.zolnierkie@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: Bartlomiej Zolnierkiewicz Cc: linux-mm@kvack.org, Michal Nazarewicz , Marek Szyprowski On Tue, Jun 19, 2012 at 03:04:59PM +0200, Bartlomiej Zolnierkiewicz wrote: > > If the page is on the wrong free list, just isolate it or move it to the > > MIGRATE_ISOLATE free list at that point. If it has been allocated then > > migrate it and move the resulting free page to the MIGRATE_ISOLATE list. > > Thanks, this makes sense but still leaves us with some page allocation vs > alloc_contig_range() races (i.e. pages "in-flight" state being added/removed > to/from pcp lists so not being on the freelists and not being allocated). > The races should not be forever or open-ended. Once the pageblock is marked ISOLATE it should only take one pass to either move it from MIGRATE_CMA to MIGRATE_ISOLATE free lists or to migrate the page and free it to the MIGRATE_ISOLATE. I would be very surprised if this cannot be properly handled in alloc_contig_range() in a manner that does not wreck the page allocator fast paths. -- Mel Gorman SUSE Labs -- 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