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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2014-12-12 16:56:01 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:48 -0800
commit48c96a3685795e52903e60c7ee115e5e22e7d640 (patch)
tree49940b1971c9b487a52b2c91b2423eee9278ced5 /lib
parent9a92a6ce6f842713ccd0025c5228fe8bea61234c (diff)
downloadop-kernel-dev-48c96a3685795e52903e60c7ee115e5e22e7d640.zip
op-kernel-dev-48c96a3685795e52903e60c7ee115e5e22e7d640.tar.gz
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: Joonsoo 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug16
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d780351..5f2ce61 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -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
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