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Commit 48c96a36 authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Linus Torvalds
Browse files

mm/page_owner: keep track of page owners 



This is the page owner tracking code which is introduced so far ago.  It
is resident on Andrew's tree, though, nobody tried to upstream so it
remain as is.  Our company uses this feature actively to debug memory leak
or to find a memory hogger so I decide to upstream this feature.

This functionality help us to know who allocates the page.  When
allocating a page, we store some information about allocation in extra
memory.  Later, if we need to know status of all pages, we can get and
analyze it from this stored information.

In previous version of this feature, extra memory is statically defined in
struct page, but, in this version, extra memory is allocated outside of
struct page.  It enables us to turn on/off this feature at boottime
without considerable memory waste.

Although we already have tracepoint for tracing page allocation/free,
using it to analyze page owner is rather complex.  We need to enlarge the
trace buffer for preventing overlapping until userspace program launched.
And, launched program continually dump out the trace buffer for later
analysis and it would change system behaviour with more possibility rather
than just keeping it in memory, so bad for debug.

Moreover, we can use page_owner feature further for various purposes.  For
example, we can use it for fragmentation statistics implemented in this
patch.  And, I also plan to implement some CMA failure debugging feature
using this interface.

I'd like to give the credit for all developers contributed this feature,
but, it's not easy because I don't know exact history.  Sorry about that.
Below is people who has "Signed-off-by" in the patches in Andrew's tree.

Contributor:
Alexander Nyberg <alexn@dsv.su.se>
Mel Gorman <mgorman@suse.de>
Dave Hansen <dave@linux.vnet.ibm.com>
Minchan Kim <minchan@kernel.org>
Michal Nazarewicz <mina86@mina86.com>
Andrew Morton <akpm@linux-foundation.org>
Jungsoo Son <jungsoo.son@lge.com>

Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9a92a6ce

Documentation/kernel-parameters.txt

+6 −0
Original line number Diff line number Diff line
@@ -2513,6 +2513,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
	OSS		[HW,OSS]

			See Documentation/sound/oss/oss-parameters.txt



	page_owner=	[KNL] Boot-time page_owner enabling option.

			Storage of the information about who allocated

			each page is disabled in default. With this switch,

			we can turn it on.

			on: enable the feature



	panic=		[KNL] Kernel behaviour on panic: delay <timeout>

			timeout > 0: seconds before rebooting

			timeout = 0: wait forever

include/linux/page_ext.h

+10 −0
Original line number Diff line number Diff line 
#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);
@@ -22,6 +25,7 @@ struct page_ext_operations { 
enum page_ext_flags {

	PAGE_EXT_DEBUG_POISON,		/* Page is poisoned */

	PAGE_EXT_DEBUG_GUARD,

	PAGE_EXT_OWNER,

};



/*
@@ -33,6 +37,12 @@ enum page_ext_flags { 
 */

struct page_ext {

	unsigned long flags;

#ifdef CONFIG_PAGE_OWNER

	unsigned int order;

	gfp_t gfp_mask;

	struct stack_trace trace;

	unsigned long trace_entries[8];

#endif

};



extern void pgdat_page_ext_init(struct pglist_data *pgdat);

include/linux/page_owner.h

0 → 100644
+38 −0
Original line number Diff line number Diff line 
#ifndef __LINUX_PAGE_OWNER_H

#define __LINUX_PAGE_OWNER_H



#ifdef CONFIG_PAGE_OWNER

extern bool page_owner_inited;

extern struct page_ext_operations page_owner_ops;



extern void __reset_page_owner(struct page *page, unsigned int order);

extern void __set_page_owner(struct page *page,

			unsigned int order, gfp_t gfp_mask);



static inline void reset_page_owner(struct page *page, unsigned int order)

{

	if (likely(!page_owner_inited))

		return;



	__reset_page_owner(page, order);

}



static inline void set_page_owner(struct page *page,

			unsigned int order, gfp_t gfp_mask)

{

	if (likely(!page_owner_inited))

		return;



	__set_page_owner(page, order, gfp_mask);

}

#else

static inline void reset_page_owner(struct page *page, unsigned int order)

{

}

static inline void set_page_owner(struct page *page,

			unsigned int order, gfp_t gfp_mask)

{

}



#endif /* CONFIG_PAGE_OWNER */

#endif /* __LINUX_PAGE_OWNER_H */

lib/Kconfig.debug

+16 −0
Original line number Diff line number Diff line
@@ -227,6 +227,22 @@ config UNUSED_SYMBOLS 
	  you really need it, and what the merge plan to the mainline kernel for

	  your module is.



config PAGE_OWNER

	bool "Track page owner"

	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT

	select DEBUG_FS

	select STACKTRACE

	select PAGE_EXTENSION

	help

	  This keeps track of what call chain is the owner of a page, may

	  help to find bare alloc_page(s) leaks. Even if you include this

	  feature on your build, it is disabled in default. You should pass

	  "page_owner=on" to boot parameter in order to enable it. Eats

	  a fair amount of memory if enabled. See tools/vm/page_owner_sort.c

	  for user-space helper.



	  If unsure, say N.



config DEBUG_FS

	bool "Debug Filesystem"

	help

mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o 
obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o

obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o

obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o

obj-$(CONFIG_PAGE_OWNER) += page_owner.o

obj-$(CONFIG_CLEANCACHE) += cleancache.o

obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o

obj-$(CONFIG_ZPOOL)	+= zpool.o