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| author | Joonsoo Kim | 2016-03-17 22:19:26 +0100 |
|---|---|---|
| committer | Linus Torvalds | 2016-03-17 23:09:34 +0100 |
| commit | fe896d1878949ea92ba547587bc3075cc688fb8f (patch) | |
| tree | 582ae505611bafae117c0de8498916485699ac78 /mm/huge_memory.c | |
| parent | mm: thp: set THP defrag by default to madvise and add a stall-free defrag option (diff) | |
| download | kernel-qcow2-linux-fe896d1878949ea92ba547587bc3075cc688fb8f.tar.gz kernel-qcow2-linux-fe896d1878949ea92ba547587bc3075cc688fb8f.tar.xz kernel-qcow2-linux-fe896d1878949ea92ba547587bc3075cc688fb8f.zip | |
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/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e08b1659ff19..bb944c771c82 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2888,7 +2888,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, page = pmd_page(*pmd); VM_BUG_ON_PAGE(!page_count(page), page); - atomic_add(HPAGE_PMD_NR - 1, &page->_count); + page_ref_add(page, HPAGE_PMD_NR - 1); write = pmd_write(*pmd); young = pmd_young(*pmd); dirty = pmd_dirty(*pmd); @@ -3257,7 +3257,7 @@ static void __split_huge_page_tail(struct page *head, int tail, struct page *page_tail = head + tail; VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail); - VM_BUG_ON_PAGE(atomic_read(&page_tail->_count) != 0, page_tail); + VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail); /* * tail_page->_count is zero and not changing from under us. But @@ -3270,7 +3270,7 @@ static void __split_huge_page_tail(struct page *head, int tail, * atomic_set() here would be safe on all archs (and not only on x86), * it's safer to use atomic_inc(). */ - atomic_inc(&page_tail->_count); + page_ref_inc(page_tail); page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; page_tail->flags |= (head->flags & |