From 60f30350fd69a3e4d5f0f45937d3274c22565134 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 15 Mar 2016 14:56:08 -0700 Subject: [PATCH] mm, page_owner: print migratetype of page and pageblock, symbolic flags The information in /sys/kernel/debug/page_owner includes the migratetype of the pageblock the page belongs to. This is also checked against the page's migratetype (as declared by gfp_flags during its allocation), and the page is reported as Fallback if its migratetype differs from the pageblock's one. t This is somewhat misleading because in fact fallback allocation is not the only reason why these two can differ. It also doesn't direcly provide the page's migratetype, although it's possible to derive that from the gfp_flags. It's arguably better to print both page and pageblock's migratetype and leave the interpretation to the consumer than to suggest fallback allocation as the only possible reason. While at it, we can print the migratetypes as string the same way as /proc/pagetypeinfo does, as some of the numeric values depend on kernel configuration. For that, this patch moves the migratetype_names array from #ifdef CONFIG_PROC_FS part of mm/vmstat.c to mm/page_alloc.c and exports it. With the new format strings for flags, we can now also provide symbolic page and gfp flags in the /sys/kernel/debug/page_owner file. This replaces the positional printing of page flags as single letters, which might have looked nicer, but was limited to a subset of flags, and required the user to remember the letters. Example page_owner entry after the patch: Page allocated via order 0, mask 0x24213ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD|__GFP_NOWARN|__GFP_NORETRY) PFN 520 type Movable Block 1 type Movable Flags 0xfffff8001006c(referenced|uptodate|lru|active|mappedtodisk) [] __alloc_pages_nodemask+0x134/0x230 [] alloc_pages_current+0x88/0x120 [] __page_cache_alloc+0xe6/0x120 [] __do_page_cache_readahead+0xdc/0x240 [] ondemand_readahead+0x135/0x260 [] page_cache_sync_readahead+0x31/0x50 [] generic_file_read_iter+0x453/0x760 [] __vfs_read+0xa7/0xd0 Signed-off-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Joonsoo Kim Cc: Minchan Kim Cc: Sasha Levin Cc: "Kirill A. Shutemov" Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 3 +++ mm/page_alloc.c | 13 +++++++++++++ mm/page_owner.c | 24 +++++++----------------- mm/vmstat.c | 13 ------------- 4 files changed, 23 insertions(+), 30 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 7b6c2cfee390..9fc23ab550a7 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -63,6 +63,9 @@ enum { MIGRATE_TYPES }; +/* In mm/page_alloc.c; keep in sync also with show_migration_types() there */ +extern char * const migratetype_names[MIGRATE_TYPES]; + #ifdef CONFIG_CMA # define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA) #else diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4e8029a7a4bf..030fafccaa6b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -223,6 +223,19 @@ static char * const zone_names[MAX_NR_ZONES] = { #endif }; +char * const migratetype_names[MIGRATE_TYPES] = { + "Unmovable", + "Movable", + "Reclaimable", + "HighAtomic", +#ifdef CONFIG_CMA + "CMA", +#endif +#ifdef CONFIG_MEMORY_ISOLATION + "Isolate", +#endif +}; + compound_page_dtor * const compound_page_dtors[] = { NULL, free_compound_page, diff --git a/mm/page_owner.c b/mm/page_owner.c index 983c3a10fa07..7a37a30d941b 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -100,8 +100,9 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, return -ENOMEM; ret = snprintf(kbuf, count, - "Page allocated via order %u, mask 0x%x\n", - page_ext->order, page_ext->gfp_mask); + "Page allocated via order %u, mask %#x(%pGg)\n", + page_ext->order, page_ext->gfp_mask, + &page_ext->gfp_mask); if (ret >= count) goto err; @@ -110,23 +111,12 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, pageblock_mt = get_pfnblock_migratetype(page, pfn); page_mt = gfpflags_to_migratetype(page_ext->gfp_mask); ret += snprintf(kbuf + ret, count - ret, - "PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n", + "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n", pfn, + migratetype_names[page_mt], pfn >> pageblock_order, - pageblock_mt, - pageblock_mt != page_mt ? "Fallback" : " ", - PageLocked(page) ? "K" : " ", - PageError(page) ? "E" : " ", - PageReferenced(page) ? "R" : " ", - PageUptodate(page) ? "U" : " ", - PageDirty(page) ? "D" : " ", - PageLRU(page) ? "L" : " ", - PageActive(page) ? "A" : " ", - PageSlab(page) ? "S" : " ", - PageWriteback(page) ? "W" : " ", - PageCompound(page) ? "C" : " ", - PageSwapCache(page) ? "B" : " ", - PageMappedToDisk(page) ? "M" : " "); + migratetype_names[pageblock_mt], + page->flags, &page->flags); if (ret >= count) goto err; diff --git a/mm/vmstat.c b/mm/vmstat.c index 084c6725b373..72c17981cb70 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -924,19 +924,6 @@ static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat, #endif #ifdef CONFIG_PROC_FS -static char * const migratetype_names[MIGRATE_TYPES] = { - "Unmovable", - "Movable", - "Reclaimable", - "HighAtomic", -#ifdef CONFIG_CMA - "CMA", -#endif -#ifdef CONFIG_MEMORY_ISOLATION - "Isolate", -#endif -}; - static void frag_show_print(struct seq_file *m, pg_data_t *pgdat, struct zone *zone) { -- 2.20.1