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authorVlastimil Babka <vbabka@suse.cz>2013-09-12 01:22:35 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 02:58:01 +0400
commit7a8010cd36273ff5f6fea5201ef9232f30cebbd9 (patch)
tree3805f3d9a8a1f1c1c555ef31bc1bdb51fb51e33e /mm/page-writeback.c
parent5b40998ae35cf64561868370e6c9f3d3e94b6bf7 (diff)
downloadlinux-7a8010cd36273ff5f6fea5201ef9232f30cebbd9.tar.xz
mm: munlock: manual pte walk in fast path instead of follow_page_mask()
Currently munlock_vma_pages_range() calls follow_page_mask() to obtain each individual struct page. This entails repeated full page table translations and page table lock taken for each page separately. This patch avoids the costly follow_page_mask() where possible, by iterating over ptes within single pmd under single page table lock. The first pte is obtained by get_locked_pte() for non-THP page acquired by the initial follow_page_mask(). The rest of the on-stack pagevec for munlock is filled up using pte_walk as long as pte_present() and vm_normal_page() are sufficient to obtain the struct page. After this patch, a 14% speedup was measured for munlocking a 56GB large memory area with THP disabled. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jörn Engel <joern@logfs.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
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