From e084b2d95e48b31aa45f9c49ffc6cdae8bdb21d4 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Wed, 29 Jul 2009 15:02:04 -0700 Subject: page-allocator: preserve PFN ordering when __GFP_COLD is set Fix a post-2.6.24 performace regression caused by 3dfa5721f12c3d5a441448086bee156887daa961 ("page-allocator: preserve PFN ordering when __GFP_COLD is set"). Narayanan reports "The regression is around 15%. There is no disk controller as our setup is based on Samsung OneNAND used as a memory mapped device on a OMAP2430 based board." The page allocator tries to preserve contiguous PFN ordering when returning pages such that repeated callers to the allocator have a strong chance of getting physically contiguous pages, particularly when external fragmentation is low. However, of the bulk of the allocations have __GFP_COLD set as they are due to aio_read() for example, then the PFNs are in reverse PFN order. This can cause performance degration when used with IO controllers that could have merged the requests. This patch attempts to preserve the contiguous ordering of PFNs for users of __GFP_COLD. Signed-off-by: Mel Gorman Reported-by: Narayananu Gopalakrishnan Tested-by: Narayanan Gopalakrishnan Cc: KAMEZAWA Hiroyuki Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index caa92689aac9..ae28c22a7fdb 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -882,7 +882,7 @@ retry_reserve: */ static int rmqueue_bulk(struct zone *zone, unsigned int order, unsigned long count, struct list_head *list, - int migratetype) + int migratetype, int cold) { int i; @@ -901,7 +901,10 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, * merge IO requests if the physical pages are ordered * properly. */ - list_add(&page->lru, list); + if (likely(cold == 0)) + list_add(&page->lru, list); + else + list_add_tail(&page->lru, list); set_page_private(page, migratetype); list = &page->lru; } @@ -1119,7 +1122,8 @@ again: local_irq_save(flags); if (!pcp->count) { pcp->count = rmqueue_bulk(zone, 0, - pcp->batch, &pcp->list, migratetype); + pcp->batch, &pcp->list, + migratetype, cold); if (unlikely(!pcp->count)) goto failed; } @@ -1138,7 +1142,8 @@ again: /* Allocate more to the pcp list if necessary */ if (unlikely(&page->lru == &pcp->list)) { pcp->count += rmqueue_bulk(zone, 0, - pcp->batch, &pcp->list, migratetype); + pcp->batch, &pcp->list, + migratetype, cold); page = list_entry(pcp->list.next, struct page, lru); } -- cgit v1.2.2 From 6583bb64fc370842b32a87c67750c26f6d559af0 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Wed, 29 Jul 2009 15:02:06 -0700 Subject: mm: avoid endless looping for oom killed tasks If a task is oom killed and still cannot find memory when trying with no watermarks, it's better to fail the allocation attempt than to loop endlessly. Direct reclaim has already failed and the oom killer will be a no-op since current has yet to die, so there is no other alternative for allocations that are not __GFP_NOFAIL. Acked-by: Mel Gorman Signed-off-by: David Rientjes Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ae28c22a7fdb..2dbb2fc68837 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1794,6 +1794,10 @@ rebalance: if (p->flags & PF_MEMALLOC) goto nopage; + /* Avoid allocations with no watermarks from looping endlessly */ + if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL)) + goto nopage; + /* Try direct reclaim and then allocating */ page = __alloc_pages_direct_reclaim(gfp_mask, order, zonelist, high_zoneidx, -- cgit v1.2.2 From 1fc28b70fe2dbf87e061b6ce5091a1f8e4e5d4e7 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Wed, 29 Jul 2009 15:04:08 -0700 Subject: page-allocator: allow too high-order warning messages to be suppressed with __GFP_NOWARN The page allocator warns once when an order >= MAX_ORDER is specified. This is to catch callers of the allocator that are always falling back to their worst-case when it was not expected. However, there are cases where the caller is behaving correctly but cannot suppress the warning. This patch allows the warning to be suppressed by the callers by specifying __GFP_NOWARN. Signed-off-by: Mel Gorman Acked-by: David Rientjes Cc: Arnaldo Carvalho de Melo Cc: "David S. Miller" Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2dbb2fc68837..d052abbe3063 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1745,8 +1745,10 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, * be using allocators in order of preference for an area that is * too large. */ - if (WARN_ON_ONCE(order >= MAX_ORDER)) + if (order >= MAX_ORDER) { + WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN)); return NULL; + } /* * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and -- cgit v1.2.2 From 7f9cfb31030737a7fc9a1cbca3fd01bec184c849 Mon Sep 17 00:00:00 2001 From: Bo Liu Date: Tue, 18 Aug 2009 14:11:19 -0700 Subject: mm: build_zonelists(): move clear node_load[] to __build_all_zonelists() If node_load[] is cleared everytime build_zonelists() is called,node_load[] will have no help to find the next node that should appear in the given node's fallback list. Because of the bug, zonelist's node_order is not calculated as expected. This bug affects on big machine, which has asynmetric node distance. [synmetric NUMA's node distance] 0 1 2 0 10 12 12 1 12 10 12 2 12 12 10 [asynmetric NUMA's node distance] 0 1 2 0 10 12 20 1 12 10 14 2 20 14 10 This (my bug) is very old but no one has reported this for a long time. Maybe because the number of asynmetric NUMA is very small and they use cpuset for customizing node memory allocation fallback. [akpm@linux-foundation.org: fix CONFIG_NUMA=n build] Signed-off-by: Bo Liu Reviewed-by: KAMEZAWA Hiroyuki Cc: Mel Gorman Cc: Christoph Lameter Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d052abbe3063..5cc986eb9f6f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2544,7 +2544,6 @@ static void build_zonelists(pg_data_t *pgdat) prev_node = local_node; nodes_clear(used_mask); - memset(node_load, 0, sizeof(node_load)); memset(node_order, 0, sizeof(node_order)); j = 0; @@ -2653,6 +2652,9 @@ static int __build_all_zonelists(void *dummy) { int nid; +#ifdef CONFIG_NUMA + memset(node_load, 0, sizeof(node_load)); +#endif for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); -- cgit v1.2.2