From 4e462112e98f9ad6dd62e160f8b14c7df5fed2fc Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 15 Mar 2016 14:56:21 -0700 Subject: mm, page_owner: dump page owner info from dump_page() The page_owner mechanism is useful for dealing with memory leaks. By reading /sys/kernel/debug/page_owner one can determine the stack traces leading to allocations of all pages, and find e.g. a buggy driver. This information might be also potentially useful for debugging, such as the VM_BUG_ON_PAGE() calls to dump_page(). So let's print the stored info from dump_page(). Example output: page:ffffea000292f1c0 count:1 mapcount:0 mapping:ffff8800b2f6cc18 index:0x91d flags: 0x1fffff8001002c(referenced|uptodate|lru|mappedtodisk) page dumped because: VM_BUG_ON_PAGE(1) page->mem_cgroup:ffff8801392c5000 page allocated via order 0, migratetype Movable, gfp_mask 0x24213ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD|__GFP_NOWARN|__GFP_NORETRY) [] __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_async_readahead+0x6c/0x70 [] generic_file_read_iter+0x3f2/0x760 [] __vfs_read+0xa7/0xd0 page has been migrated, last migrate reason: compaction 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 --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 030fafccaa6b..d98672d33752 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -443,6 +443,7 @@ static void bad_page(struct page *page, const char *reason, printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n", current->comm, page_to_pfn(page)); dump_page_badflags(page, reason, bad_flags); + dump_page_owner(page); print_modules(); dump_stack(); -- cgit v1.2.3-70-g09d2