Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762105AbXEJXA6 (ORCPT ); Thu, 10 May 2007 19:00:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754359AbXEJXAt (ORCPT ); Thu, 10 May 2007 19:00:49 -0400 Received: from calculon.skynet.ie ([193.1.99.88]:56292 "EHLO calculon.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754068AbXEJXAr (ORCPT ); Thu, 10 May 2007 19:00:47 -0400 Date: Fri, 11 May 2007 00:00:44 +0100 To: Christoph Lameter , Nicolas.Mailhot@LaPoste.net Cc: Mel Gorman , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "bugme-daemon@kernel-bugs.osdl.org" Subject: Re: [Bug 8464] New: autoreconf: page allocation failure. order:2, mode:0x84020 Message-ID: <20070510230044.GB15332@skynet.ie> References: <200705102128.l4ALSI2A017437@fire-2.osdl.org> <20070510144319.48d2841a.akpm@linux-foundation.org> <20070510220657.GA14694@skynet.ie> <20070510221607.GA15084@skynet.ie> <20070510224441.GA15332@skynet.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) From: mel@skynet.skynet.ie (Mel Gorman) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7394 Lines: 172 On (10/05/07 15:49), Christoph Lameter didst pronounce: > On Thu, 10 May 2007, Mel Gorman wrote: > > > > I cannot predict how allocations on a slab will be performed. In order > > > to avoid the higher order allocations in we would have to add a flag > > > that tells SLUB at slab creation creation time that this cache will be > > > used for atomic allocs and thus we can avoid configuring slabs in such a > > > way that they use higher order allocs. > > > > > > > It is an option. I had the gfp flags passed in to kmem_cache_create() in > > mind for determining this but SLUB creates slabs differently and different > > flags could be passed into kmem_cache_alloc() of course. > > So we have a collection of flags to add > > SLAB_USES_ATOMIC This is a possibility. > SLAB_TEMPORARY I have a patch for this sitting in a queue waiting for testing > SLAB_PERSISTENT > SLAB_RECLAIMABLE > SLAB_MOVABLE I don't think these are required because the necessary information is available from the GFP flags. > > ? > > > Another alternative is that anti-frag used to also group high-order > > allocations together and make it hard to fallback to those areas > > for non-atomic allocations. It is currently backed out by the > > patch dont-group-high-order-atomic-allocations.patch because > > it was intended for rare high-order short-lived allocations > > such as e1000 that are currently dealt with by MIGRATE_RESERVE > > (bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks.patch) > > The high-order atomic groupings may help here because the high-order > > allocations are long-lived and would claim contiguous areas. > > > > The last alternative I think I mentioned already is to have the minimum > > order kswapd reclaims as the same order SLUB uses instead of 0 so that > > min_free_kbytes is kept at higher orders than current. > > Would you get a patch to Nicholas to test either of these solutions? I do not have a kswapd related patch ready but the first alternative is readily available. Nicholas, could you backout the patch dont-group-high-order-atomic-allocations.patch and test again please? The following patch has the same effect. Thanks diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.21-mm2-clean/include/linux/mmzone.h linux-2.6.21-mm2-grouphigh/include/linux/mmzone.h --- linux-2.6.21-mm2-clean/include/linux/mmzone.h 2007-05-09 10:21:28.000000000 +0100 +++ linux-2.6.21-mm2-grouphigh/include/linux/mmzone.h 2007-05-10 23:54:45.000000000 +0100 @@ -38,8 +38,9 @@ extern int page_group_by_mobility_disabl #define MIGRATE_UNMOVABLE 0 #define MIGRATE_RECLAIMABLE 1 #define MIGRATE_MOVABLE 2 -#define MIGRATE_RESERVE 3 -#define MIGRATE_TYPES 4 +#define MIGRATE_HIGHATOMIC 3 +#define MIGRATE_RESERVE 4 +#define MIGRATE_TYPES 5 #define for_each_migratetype_order(order, type) \ for (order = 0; order < MAX_ORDER; order++) \ diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.21-mm2-clean/include/linux/pageblock-flags.h linux-2.6.21-mm2-grouphigh/include/linux/pageblock-flags.h --- linux-2.6.21-mm2-clean/include/linux/pageblock-flags.h 2007-05-09 10:21:28.000000000 +0100 +++ linux-2.6.21-mm2-grouphigh/include/linux/pageblock-flags.h 2007-05-10 23:54:45.000000000 +0100 @@ -31,7 +31,7 @@ /* Bit indices that affect a whole block of pages */ enum pageblock_bits { - PB_range(PB_migrate, 2), /* 2 bits required for migrate types */ + PB_range(PB_migrate, 3), /* 3 bits required for migrate types */ NR_PAGEBLOCK_BITS }; diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.21-mm2-clean/mm/page_alloc.c linux-2.6.21-mm2-grouphigh/mm/page_alloc.c --- linux-2.6.21-mm2-clean/mm/page_alloc.c 2007-05-09 10:21:28.000000000 +0100 +++ linux-2.6.21-mm2-grouphigh/mm/page_alloc.c 2007-05-10 23:54:45.000000000 +0100 @@ -167,6 +167,11 @@ static inline int allocflags_to_migratet if (unlikely(page_group_by_mobility_disabled)) return MIGRATE_UNMOVABLE; + /* Cluster high-order atomic allocations together */ + if (unlikely(order > 0) && + (!(gfp_flags & __GFP_WAIT) || in_interrupt())) + return MIGRATE_HIGHATOMIC; + /* Cluster based on mobility */ return (((gfp_flags & __GFP_MOVABLE) != 0) << 1) | ((gfp_flags & __GFP_RECLAIMABLE) != 0); @@ -713,10 +718,11 @@ static struct page *__rmqueue_smallest(s * the free lists for the desirable migrate type are depleted */ static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = { - [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE }, - [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE }, - [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE }, - [MIGRATE_RESERVE] = { MIGRATE_RESERVE, MIGRATE_RESERVE, MIGRATE_RESERVE }, /* Never used */ + [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_HIGHATOMIC, MIGRATE_RESERVE }, + [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_HIGHATOMIC, MIGRATE_RESERVE }, + [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_HIGHATOMIC, MIGRATE_RESERVE }, + [MIGRATE_HIGHATOMIC] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE }, + [MIGRATE_RESERVE] = { MIGRATE_RESERVE, MIGRATE_RESERVE, MIGRATE_RESERVE, MIGRATE_RESERVE }, /* Never used */ }; /* @@ -810,7 +816,9 @@ static struct page *__rmqueue_fallback(s int current_order; struct page *page; int migratetype, i; + int nonatomic_fallback_atomic = 0; +retry: /* Find the largest possible block of pages in the other list */ for (current_order = MAX_ORDER-1; current_order >= order; --current_order) { @@ -820,6 +828,14 @@ static struct page *__rmqueue_fallback(s /* MIGRATE_RESERVE handled later if necessary */ if (migratetype == MIGRATE_RESERVE) continue; + /* + * Make it hard to fallback to blocks used for + * high-order atomic allocations + */ + if (migratetype == MIGRATE_HIGHATOMIC && + start_migratetype != MIGRATE_UNMOVABLE && + !nonatomic_fallback_atomic) + continue; area = &(zone->free_area[current_order]); if (list_empty(&area->free_list[migratetype])) @@ -845,7 +861,8 @@ static struct page *__rmqueue_fallback(s start_migratetype); /* Claim the whole block if over half of it is free */ - if ((pages << current_order) >= (1 << (MAX_ORDER-2))) + if ((pages << current_order) >= (1 << (MAX_ORDER-2)) && + migratetype != MIGRATE_HIGHATOMIC) set_pageblock_migratetype(page, start_migratetype); @@ -867,6 +884,12 @@ static struct page *__rmqueue_fallback(s } } + /* Allow fallback to high-order atomic blocks if memory is that low */ + if (!nonatomic_fallback_atomic) { + nonatomic_fallback_atomic = 1; + goto retry; + } + /* Use MIGRATE_RESERVE rather than fail an allocation */ return __rmqueue_smallest(zone, order, MIGRATE_RESERVE); } -- 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/