From 188f10f240d08a24a6ad1d96bd5b3038ce1dd05b Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 15 Mar 2016 14:56:08 -0700 Subject: 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 Change-Id: I08f3412dbda9075d5534eee81444843a7679e54e 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 Git-commit: 60f30350fd69a3e4d5f0f45937d3274c22565134 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git [guptap@codeaurora.org: resolve trivial merge conflicts] Signed-off-by: Prakash Gupta --- include/linux/mmzone.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 9d1161a8d6b7..2b1be7efde55 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -71,6 +71,9 @@ enum { */ extern int *get_migratetype_fallbacks(int mtype); +/* In mm/page_alloc.c; keep in sync also with show_migration_types() there */ +extern char * const migratetype_names[MIGRATE_TYPES]; + #ifdef CONFIG_CMA bool is_cma_pageblock(struct page *page); # define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA) -- cgit v1.2.3