From 377e4f167664d8bc390c04c911d846366000159c Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Tue, 11 Dec 2012 16:00:24 -0800 Subject: [PATCH] mm: show migration types in show_mem This is useful to diagnose the reason for page allocation failure for cases where there appear to be several free pages. Example, with this alloc_pages(GFP_ATOMIC) failure: swapper/0: page allocation failure: order:0, mode:0x0 ... Mem-info: Normal per-cpu: CPU 0: hi: 90, btch: 15 usd: 48 CPU 1: hi: 90, btch: 15 usd: 21 active_anon:0 inactive_anon:0 isolated_anon:0 active_file:0 inactive_file:84 isolated_file:0 unevictable:0 dirty:0 writeback:0 unstable:0 free:4026 slab_reclaimable:75 slab_unreclaimable:484 mapped:0 shmem:0 pagetables:0 bounce:0 Normal free:16104kB min:2296kB low:2868kB high:3444kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:336kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:331776kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:300kB slab_unreclaimable:1936kB kernel_stack:328kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 Before the patch, it's hard (for me, at least) to say why all these free chunks weren't considered for allocation: Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 1*256kB 1*512kB 1*1024kB 1*2048kB 3*4096kB = 16128kB After the patch, it's obvious that the reason is that all of these are in the MIGRATE_CMA (C) freelist: Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 1*256kB (C) 1*512kB (C) 1*1024kB (C) 1*2048kB (C) 3*4096kB (C) = 16128kB Signed-off-by: Rabin Vincent Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 42 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7e208f0ad68c..dc018b486b74 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2877,6 +2877,31 @@ out: #define K(x) ((x) << (PAGE_SHIFT-10)) +static void show_migration_types(unsigned char type) +{ + static const char types[MIGRATE_TYPES] = { + [MIGRATE_UNMOVABLE] = 'U', + [MIGRATE_RECLAIMABLE] = 'E', + [MIGRATE_MOVABLE] = 'M', + [MIGRATE_RESERVE] = 'R', +#ifdef CONFIG_CMA + [MIGRATE_CMA] = 'C', +#endif + [MIGRATE_ISOLATE] = 'I', + }; + char tmp[MIGRATE_TYPES + 1]; + char *p = tmp; + int i; + + for (i = 0; i < MIGRATE_TYPES; i++) { + if (type & (1 << i)) + *p++ = types[i]; + } + + *p = '\0'; + printk("(%s) ", tmp); +} + /* * Show free area list (used inside shift_scroll-lock stuff) * We also calculate the percentage fragmentation. We do this by counting the @@ -3005,6 +3030,7 @@ void show_free_areas(unsigned int filter) for_each_populated_zone(zone) { unsigned long nr[MAX_ORDER], flags, order, total = 0; + unsigned char types[MAX_ORDER]; if (skip_free_areas_node(filter, zone_to_nid(zone))) continue; @@ -3013,12 +3039,24 @@ void show_free_areas(unsigned int filter) spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { - nr[order] = zone->free_area[order].nr_free; + struct free_area *area = &zone->free_area[order]; + int type; + + nr[order] = area->nr_free; total += nr[order] << order; + + types[order] = 0; + for (type = 0; type < MIGRATE_TYPES; type++) { + if (!list_empty(&area->free_list[type])) + types[order] |= 1 << type; + } } spin_unlock_irqrestore(&zone->lock, flags); - for (order = 0; order < MAX_ORDER; order++) + for (order = 0; order < MAX_ORDER; order++) { printk("%lu*%lukB ", nr[order], K(1UL) << order); + if (nr[order]) + show_migration_types(types[order]); + } printk("= %lukB\n", K(total)); } -- 2.30.2