From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mel Gorman Message-Id: <20060907190442.6166.90028.sendpatchset@skynet.skynet.ie> In-Reply-To: <20060907190342.6166.49732.sendpatchset@skynet.skynet.ie> References: <20060907190342.6166.49732.sendpatchset@skynet.skynet.ie> Subject: [PATCH 3/8] Split the per-cpu lists into kernel and user parts Date: Thu, 7 Sep 2006 20:04:42 +0100 (IST) Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Mel Gorman List-ID: The freelists for each allocation type can slowly become fragmented due to the per-cpu list. Consider what happens when the following happens 1. A 2^(MAX_ORDER-1) list is reserved for __GFP_EASYRCLM pages 2. An order-0 page is allocated from the newly reserved block 3. The page is freed and placed on the per-cpu list 4. alloc_page() is called with GFP_KERNEL as the gfp_mask 5. The per-cpu list is used to satisfy the allocation This results in a kernel page is in the middle of a RCLM_EASY region. This means that over long periods of the time, the anti-fragmentation scheme slowly degrades to the standard allocator. This patch divides the per-cpu lists into RCLM_TYPES number of lists. Signed-off-by: Mel Gorman Signed-off-by: Joel Schopp --- include/linux/mmzone.h | 16 +++++++++-- mm/page_alloc.c | 63 +++++++++++++++++++++++++++----------------- mm/vmstat.c | 4 +- 3 files changed, 56 insertions(+), 27 deletions(-) diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.18-rc5-mm1-002_fragcore/include/linux/mmzone.h linux-2.6.18-rc5-mm1-003_percpu/include/linux/mmzone.h --- linux-2.6.18-rc5-mm1-002_fragcore/include/linux/mmzone.h 2006-09-04 18:37:59.000000000 +0100 +++ linux-2.6.18-rc5-mm1-003_percpu/include/linux/mmzone.h 2006-09-04 18:39:39.000000000 +0100 @@ -28,6 +28,8 @@ #define RCLM_EASY 1 #define RCLM_TYPES 2 +#define for_each_rclmtype(type) \ + for (type = 0; type < RCLM_TYPES; type++) #define for_each_rclmtype_order(type, order) \ for (order = 0; order < MAX_ORDER; order++) \ for (type = 0; type < RCLM_TYPES; type++) @@ -77,10 +79,10 @@ enum zone_stat_item { NR_VM_ZONE_STAT_ITEMS }; struct per_cpu_pages { - int count; /* number of pages in the list */ + int counts[RCLM_TYPES]; /* number of pages in the list */ int high; /* high watermark, emptying needed */ int batch; /* chunk size for buddy add/remove */ - struct list_head list; /* the list of pages */ + struct list_head list[RCLM_TYPES]; /* the list of pages */ }; struct per_cpu_pageset { @@ -91,6 +93,16 @@ struct per_cpu_pageset { #endif } ____cacheline_aligned_in_smp; +static inline int pcp_count(struct per_cpu_pages *pcp) +{ + int rclmtype, count = 0; + + for_each_rclmtype(rclmtype) + count += pcp->counts[rclmtype]; + + return count; +} + #ifdef CONFIG_NUMA #define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)]) #else diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.18-rc5-mm1-002_fragcore/mm/page_alloc.c linux-2.6.18-rc5-mm1-003_percpu/mm/page_alloc.c --- linux-2.6.18-rc5-mm1-002_fragcore/mm/page_alloc.c 2006-09-04 18:37:59.000000000 +0100 +++ linux-2.6.18-rc5-mm1-003_percpu/mm/page_alloc.c 2006-09-04 18:39:39.000000000 +0100 @@ -745,7 +745,7 @@ static int rmqueue_bulk(struct zone *zon */ void drain_node_pages(int nodeid) { - int i; + int i, pindex; enum zone_type z; unsigned long flags; @@ -761,10 +761,14 @@ void drain_node_pages(int nodeid) struct per_cpu_pages *pcp; pcp = &pset->pcp[i]; - if (pcp->count) { + if (pcp_count(pcp)) { local_irq_save(flags); - free_pages_bulk(zone, pcp->count, &pcp->list, 0); - pcp->count = 0; + for_each_rclmtype(pindex) { + free_pages_bulk(zone, + pcp->counts[pindex], + &pcp->list[pindex], 0); + pcp->counts[pindex] = 0; + } local_irq_restore(flags); } } @@ -777,7 +781,7 @@ static void __drain_pages(unsigned int c { unsigned long flags; struct zone *zone; - int i; + int i, pindex; for_each_zone(zone) { struct per_cpu_pageset *pset; @@ -788,8 +792,13 @@ static void __drain_pages(unsigned int c pcp = &pset->pcp[i]; local_irq_save(flags); - free_pages_bulk(zone, pcp->count, &pcp->list, 0); - pcp->count = 0; + for_each_rclmtype(pindex) { + free_pages_bulk(zone, + pcp->counts[pindex], + &pcp->list[pindex], 0); + + pcp->counts[pindex] = 0; + } local_irq_restore(flags); } } @@ -851,6 +860,7 @@ void drain_local_pages(void) static void fastcall free_hot_cold_page(struct page *page, int cold) { struct zone *zone = page_zone(page); + int pindex = get_pageblock_type(page); struct per_cpu_pages *pcp; unsigned long flags; @@ -866,11 +876,11 @@ static void fastcall free_hot_cold_page( pcp = &zone_pcp(zone, get_cpu())->pcp[cold]; local_irq_save(flags); __count_vm_event(PGFREE); - list_add(&page->lru, &pcp->list); - pcp->count++; - if (pcp->count >= pcp->high) { - free_pages_bulk(zone, pcp->batch, &pcp->list, 0); - pcp->count -= pcp->batch; + list_add(&page->lru, &pcp->list[pindex]); + pcp->counts[pindex]++; + if (pcp->counts[pindex] >= pcp->high) { + free_pages_bulk(zone, pcp->batch, &pcp->list[pindex], 0); + pcp->counts[pindex] -= pcp->batch; } local_irq_restore(flags); put_cpu(); @@ -916,6 +926,7 @@ static struct page *buffered_rmqueue(str struct page *page; int cold = !!(gfp_flags & __GFP_COLD); int cpu; + int rclmtype = gfpflags_to_rclmtype(gfp_flags); again: cpu = get_cpu(); @@ -924,15 +935,15 @@ again: pcp = &zone_pcp(zone, cpu)->pcp[cold]; local_irq_save(flags); - if (!pcp->count) { - pcp->count += rmqueue_bulk(zone, 0, - pcp->batch, &pcp->list, gfp_flags); - if (unlikely(!pcp->count)) + if (!pcp->counts[rclmtype]) { + pcp->counts[rclmtype] += rmqueue_bulk(zone, 0, + pcp->batch, &pcp->list[rclmtype], gfp_flags); + if (unlikely(!pcp->counts[rclmtype])) goto failed; } - page = list_entry(pcp->list.next, struct page, lru); + page = list_entry(pcp->list[rclmtype].next, struct page, lru); list_del(&page->lru); - pcp->count--; + pcp->counts[rclmtype]--; } else { spin_lock_irqsave(&zone->lock, flags); page = __rmqueue(zone, order, gfp_flags); @@ -1480,7 +1491,7 @@ void show_free_areas(void) temperature ? "cold" : "hot", pageset->pcp[temperature].high, pageset->pcp[temperature].batch, - pageset->pcp[temperature].count); + pcp_count(&pageset->pcp[temperature])); } } @@ -1921,20 +1932,26 @@ static int __cpuinit zone_batchsize(stru inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch) { struct per_cpu_pages *pcp; + int rclmtype; memset(p, 0, sizeof(*p)); pcp = &p->pcp[0]; /* hot */ - pcp->count = 0; + for_each_rclmtype(rclmtype) { + pcp->counts[rclmtype] = 0; + INIT_LIST_HEAD(&pcp->list[rclmtype]); + } pcp->high = 6 * batch; pcp->batch = max(1UL, 1 * batch); - INIT_LIST_HEAD(&pcp->list); + INIT_LIST_HEAD(&pcp->list[RCLM_EASY]); pcp = &p->pcp[1]; /* cold*/ - pcp->count = 0; + for_each_rclmtype(rclmtype) { + pcp->counts[rclmtype] = 0; + INIT_LIST_HEAD(&pcp->list[rclmtype]); + } pcp->high = 2 * batch; pcp->batch = max(1UL, batch/2); - INIT_LIST_HEAD(&pcp->list); } /* diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.18-rc5-mm1-002_fragcore/mm/vmstat.c linux-2.6.18-rc5-mm1-003_percpu/mm/vmstat.c --- linux-2.6.18-rc5-mm1-002_fragcore/mm/vmstat.c 2006-09-04 18:34:33.000000000 +0100 +++ linux-2.6.18-rc5-mm1-003_percpu/mm/vmstat.c 2006-09-04 18:39:39.000000000 +0100 @@ -562,7 +562,7 @@ static int zoneinfo_show(struct seq_file pageset = zone_pcp(zone, i); for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) { - if (pageset->pcp[j].count) + if (pcp_count(&pageset->pcp[j])) break; } if (j == ARRAY_SIZE(pageset->pcp)) @@ -574,7 +574,7 @@ static int zoneinfo_show(struct seq_file "\n high: %i" "\n batch: %i", i, j, - pageset->pcp[j].count, + pcp_count(&pageset->pcp[j]), pageset->pcp[j].high, pageset->pcp[j].batch); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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