• Joonsoo Kim's avatar
    mm/page_alloc: restrict max order of merging on isolated pageblock · 3c605096
    Joonsoo Kim authored
    Current pageblock isolation logic could isolate each pageblock
    individually.  This causes freepage accounting problem if freepage with
    pageblock order on isolate pageblock is merged with other freepage on
    normal pageblock.  We can prevent merging by restricting max order of
    merging to pageblock order if freepage is on isolate pageblock.
    
    A side-effect of this change is that there could be non-merged buddy
    freepage even if finishing pageblock isolation, because undoing
    pageblock isolation is just to move freepage from isolate buddy list to
    normal buddy list rather than to consider merging.  So, the patch also
    makes undoing pageblock isolation consider freepage merge.  When
    un-isolation, freepage with more than pageblock order and it's buddy are
    checked.  If they are on normal pageblock, instead of just moving, we
    isolate the freepage and free it in order to get merged.
    Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
    Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
    Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: Minchan Kim <minchan@kernel.org>
    Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
    Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
    Cc: Tang Chen <tangchen@cn.fujitsu.com>
    Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
    Cc: Wen Congyang <wency@cn.fujitsu.com>
    Cc: Marek Szyprowski <m.szyprowski@samsung.com>
    Cc: Michal Nazarewicz <mina86@mina86.com>
    Cc: Laura Abbott <lauraa@codeaurora.org>
    Cc: Heesub Shin <heesub.shin@samsung.com>
    Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
    Cc: Ritesh Harjani <ritesh.list@gmail.com>
    Cc: Gioh Kim <gioh.kim@lge.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    3c605096
page_isolation.c 8.65 KB