mm, page_owner: track and print last migrate reason
During migration, page_owner info is now copied with the rest of the
page, so the stacktrace leading to free page allocation during migration
is overwritten. For debugging purposes, it might be however useful to
know that the page has been migrated since its initial allocation. This
might happen many times during the lifetime for different reasons and
fully tracking this, especially with stacktraces would incur extra
memory costs. As a compromise, store and print the migrate_reason of
the last migration that occurred to the page. This is enough to
distinguish compaction, numa balancing etc.
Example page_owner entry after the patch:
Page allocated via order 0, mask 0x24200ca(GFP_HIGHUSER_MOVABLE)
PFN 628753 type Movable Block 1228 type Movable Flags 0x1fffff80040030(dirty|lru|swapbacked)
[<ffffffff811682c4>] __alloc_pages_nodemask+0x134/0x230
[<ffffffff811b6325>] alloc_pages_vma+0xb5/0x250
[<ffffffff81177491>] shmem_alloc_page+0x61/0x90
[<ffffffff8117a438>] shmem_getpage_gfp+0x678/0x960
[<ffffffff8117c2b9>] shmem_fallocate+0x329/0x440
[<ffffffff811de600>] vfs_fallocate+0x140/0x230
[<ffffffff811df434>] SyS_fallocate+0x44/0x70
[<ffffffff8158cc2e>] entry_SYSCALL_64_fastpath+0x12/0x71
Page has been migrated, last migrate reason: compaction
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 6440daa..555893b 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -12,6 +12,7 @@
unsigned int order, gfp_t gfp_mask);
extern gfp_t __get_page_owner_gfp(struct page *page);
extern void __copy_page_owner(struct page *oldpage, struct page *newpage);
+extern void __set_page_owner_migrate_reason(struct page *page, int reason);
static inline void reset_page_owner(struct page *page, unsigned int order)
{
@@ -38,6 +39,11 @@
if (static_branch_unlikely(&page_owner_inited))
__copy_page_owner(oldpage, newpage);
}
+static inline void set_page_owner_migrate_reason(struct page *page, int reason)
+{
+ if (static_branch_unlikely(&page_owner_inited))
+ __set_page_owner_migrate_reason(page, reason);
+}
#else
static inline void reset_page_owner(struct page *page, unsigned int order)
{
@@ -53,5 +59,8 @@
static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
{
}
+static inline void set_page_owner_migrate_reason(struct page *page, int reason)
+{
+}
#endif /* CONFIG_PAGE_OWNER */
#endif /* __LINUX_PAGE_OWNER_H */