From 3dfa5721f12c3d5a441448086bee156887daa961 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Mon, 4 Feb 2008 22:29:19 -0800 Subject: [PATCH] Page allocator: get rid of the list of cold pages We have repeatedly discussed if the cold pages still have a point. There is one way to join the two lists: Use a single list and put the cold pages at the end and the hot pages at the beginning. That way a single list can serve for both types of allocations. The discussion of the RFC for this and Mel's measurements indicate that there may not be too much of a point left to having separate lists for hot and cold pages (see http://marc.info/?t=119492914200001&r=1&w=2). Signed-off-by: Christoph Lameter Cc: Mel Gorman Cc: Martin Bligh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 2 +- mm/page_alloc.c | 55 ++++++++++++++++++++---------------------- mm/vmstat.c | 30 +++++++++-------------- 3 files changed, 39 insertions(+), 48 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 4c4522a51a3b..8d8d1977736e 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -113,7 +113,7 @@ struct per_cpu_pages { }; struct per_cpu_pageset { - struct per_cpu_pages pcp[2]; /* 0: hot. 1: cold */ + struct per_cpu_pages pcp; #ifdef CONFIG_NUMA s8 expire; #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5c7de8e959fc..144c0967e702 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -901,24 +901,21 @@ static void drain_pages(unsigned int cpu) { unsigned long flags; struct zone *zone; - int i; for_each_zone(zone) { struct per_cpu_pageset *pset; + struct per_cpu_pages *pcp; if (!populated_zone(zone)) continue; pset = zone_pcp(zone, cpu); - for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) { - struct per_cpu_pages *pcp; - pcp = &pset->pcp[i]; - local_irq_save(flags); - free_pages_bulk(zone, pcp->count, &pcp->list, 0); - pcp->count = 0; - local_irq_restore(flags); - } + pcp = &pset->pcp; + local_irq_save(flags); + free_pages_bulk(zone, pcp->count, &pcp->list, 0); + pcp->count = 0; + local_irq_restore(flags); } } @@ -993,10 +990,13 @@ static void fastcall free_hot_cold_page(struct page *page, int cold) arch_free_page(page, 0); kernel_map_pages(page, 1, 0); - pcp = &zone_pcp(zone, get_cpu())->pcp[cold]; + pcp = &zone_pcp(zone, get_cpu())->pcp; local_irq_save(flags); __count_vm_event(PGFREE); - list_add(&page->lru, &pcp->list); + if (cold) + list_add_tail(&page->lru, &pcp->list); + else + list_add(&page->lru, &pcp->list); set_page_private(page, get_pageblock_migratetype(page)); pcp->count++; if (pcp->count >= pcp->high) { @@ -1054,7 +1054,7 @@ static struct page *buffered_rmqueue(struct zonelist *zonelist, if (likely(order == 0)) { struct per_cpu_pages *pcp; - pcp = &zone_pcp(zone, cpu)->pcp[cold]; + pcp = &zone_pcp(zone, cpu)->pcp; local_irq_save(flags); if (!pcp->count) { pcp->count = rmqueue_bulk(zone, 0, @@ -1064,9 +1064,15 @@ static struct page *buffered_rmqueue(struct zonelist *zonelist, } /* Find a page of the appropriate migrate type */ - list_for_each_entry(page, &pcp->list, lru) - if (page_private(page) == migratetype) - break; + if (cold) { + list_for_each_entry_reverse(page, &pcp->list, lru) + if (page_private(page) == migratetype) + break; + } else { + list_for_each_entry(page, &pcp->list, lru) + if (page_private(page) == migratetype) + break; + } /* Allocate more to the pcp list if necessary */ if (unlikely(&page->lru == &pcp->list)) { @@ -1793,12 +1799,9 @@ void show_free_areas(void) pageset = zone_pcp(zone, cpu); - printk("CPU %4d: Hot: hi:%5d, btch:%4d usd:%4d " - "Cold: hi:%5d, btch:%4d usd:%4d\n", - cpu, pageset->pcp[0].high, - pageset->pcp[0].batch, pageset->pcp[0].count, - pageset->pcp[1].high, pageset->pcp[1].batch, - pageset->pcp[1].count); + printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n", + cpu, pageset->pcp.high, + pageset->pcp.batch, pageset->pcp.count); } } @@ -2596,17 +2599,11 @@ inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch) memset(p, 0, sizeof(*p)); - pcp = &p->pcp[0]; /* hot */ + pcp = &p->pcp; pcp->count = 0; pcp->high = 6 * batch; pcp->batch = max(1UL, 1 * batch); INIT_LIST_HEAD(&pcp->list); - - pcp = &p->pcp[1]; /* cold*/ - pcp->count = 0; - pcp->high = 2 * batch; - pcp->batch = max(1UL, batch/2); - INIT_LIST_HEAD(&pcp->list); } /* @@ -2619,7 +2616,7 @@ static void setup_pagelist_highmark(struct per_cpu_pageset *p, { struct per_cpu_pages *pcp; - pcp = &p->pcp[0]; /* hot list */ + pcp = &p->pcp; pcp->high = high; pcp->batch = max(1UL, high/4); if ((high/4) > (PAGE_SHIFT * 8)) diff --git a/mm/vmstat.c b/mm/vmstat.c index 9ffc573ceb6e..888668e0b7db 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -337,7 +337,7 @@ void refresh_cpu_vm_stats(int cpu) * Check if there are pages remaining in this pageset * if not then there is nothing to expire. */ - if (!p->expire || (!p->pcp[0].count && !p->pcp[1].count)) + if (!p->expire || !p->pcp.count) continue; /* @@ -352,11 +352,8 @@ void refresh_cpu_vm_stats(int cpu) if (p->expire) continue; - if (p->pcp[0].count) - drain_zone_pages(zone, p->pcp + 0); - - if (p->pcp[1].count) - drain_zone_pages(zone, p->pcp + 1); + if (p->pcp.count) + drain_zone_pages(zone, &p->pcp); #endif } @@ -693,20 +690,17 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, "\n pagesets"); for_each_online_cpu(i) { struct per_cpu_pageset *pageset; - int j; pageset = zone_pcp(zone, i); - for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) { - seq_printf(m, - "\n cpu: %i pcp: %i" - "\n count: %i" - "\n high: %i" - "\n batch: %i", - i, j, - pageset->pcp[j].count, - pageset->pcp[j].high, - pageset->pcp[j].batch); - } + seq_printf(m, + "\n cpu: %i" + "\n count: %i" + "\n high: %i" + "\n batch: %i", + i, + pageset->pcp.count, + pageset->pcp.high, + pageset->pcp.batch); #ifdef CONFIG_SMP seq_printf(m, "\n vm stats threshold: %d", pageset->stat_threshold);