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linux-next/include/linux/page_ext.h
Vlastimil Babka 7cd12b4abf 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>
2016-03-15 16:55:16 -07:00

90 lines
1.9 KiB
C

#ifndef __LINUX_PAGE_EXT_H
#define __LINUX_PAGE_EXT_H
#include <linux/types.h>
#include <linux/stacktrace.h>
struct pglist_data;
struct page_ext_operations {
bool (*need)(void);
void (*init)(void);
};
#ifdef CONFIG_PAGE_EXTENSION
/*
* page_ext->flags bits:
*
* PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to
* implement generic debug pagealloc feature. The pages are filled with
* poison patterns and set this flag after free_pages(). The poisoned
* pages are verified whether the patterns are not corrupted and clear
* the flag before alloc_pages().
*/
enum page_ext_flags {
PAGE_EXT_DEBUG_POISON, /* Page is poisoned */
PAGE_EXT_DEBUG_GUARD,
PAGE_EXT_OWNER,
#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
PAGE_EXT_YOUNG,
PAGE_EXT_IDLE,
#endif
};
/*
* Page Extension can be considered as an extended mem_map.
* A page_ext page is associated with every page descriptor. The
* page_ext helps us add more information about the page.
* All page_ext are allocated at boot or memory hotplug event,
* then the page_ext for pfn always exists.
*/
struct page_ext {
unsigned long flags;
#ifdef CONFIG_PAGE_OWNER
unsigned int order;
gfp_t gfp_mask;
unsigned int nr_entries;
int last_migrate_reason;
unsigned long trace_entries[8];
#endif
};
extern void pgdat_page_ext_init(struct pglist_data *pgdat);
#ifdef CONFIG_SPARSEMEM
static inline void page_ext_init_flatmem(void)
{
}
extern void page_ext_init(void);
#else
extern void page_ext_init_flatmem(void);
static inline void page_ext_init(void)
{
}
#endif
struct page_ext *lookup_page_ext(struct page *page);
#else /* !CONFIG_PAGE_EXTENSION */
struct page_ext;
static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
{
}
static inline struct page_ext *lookup_page_ext(struct page *page)
{
return NULL;
}
static inline void page_ext_init(void)
{
}
static inline void page_ext_init_flatmem(void)
{
}
#endif /* CONFIG_PAGE_EXTENSION */
#endif /* __LINUX_PAGE_EXT_H */