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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2016-03-17 14:19:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 15:09:34 -0700
commitfe896d1878949ea92ba547587bc3075cc688fb8f (patch)
tree582ae505611bafae117c0de8498916485699ac78 /mm/vmscan.c
parent444eb2a449ef36fe115431ed7b71467c4563c7f1 (diff)
downloadlinux-fe896d1878949ea92ba547587bc3075cc688fb8f.tar.bz2
mm: introduce page reference manipulation functions
The success of CMA allocation largely depends on the success of migration and key factor of it is page reference count. Until now, page reference is manipulated by direct calling atomic functions so we cannot follow up who and where manipulate it. Then, it is hard to find actual reason of CMA allocation failure. CMA allocation should be guaranteed to succeed so finding offending place is really important. In this patch, call sites where page reference is manipulated are converted to introduced wrapper function. This is preparation step to add tracepoint to each page reference manipulation function. With this facility, we can easily find reason of CMA allocation failure. There is no functional change in this patch. In addition, this patch also converts reference read sites. It will help a second step that renames page._count to something else and prevents later attempt to direct access to it (Suggested by Andrew). Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b41b82d4bab1..b934223eaa45 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -638,11 +638,11 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
* Note that if SetPageDirty is always performed via set_page_dirty,
* and thus under tree_lock, then this ordering is not required.
*/
- if (!page_freeze_refs(page, 2))
+ if (!page_ref_freeze(page, 2))
goto cannot_free;
/* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */
if (unlikely(PageDirty(page))) {
- page_unfreeze_refs(page, 2);
+ page_ref_unfreeze(page, 2);
goto cannot_free;
}
@@ -704,7 +704,7 @@ int remove_mapping(struct address_space *mapping, struct page *page)
* drops the pagecache ref for us without requiring another
* atomic operation.
*/
- page_unfreeze_refs(page, 1);
+ page_ref_unfreeze(page, 1);
return 1;
}
return 0;