• Minchan Kim's avatar
    mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called · b8d3c4c3
    Minchan Kim authored
    We don't need to split THP page when MADV_FREE syscall is called if
    [start, len] is aligned with THP size.  The split could be done when VM
    decide to free it in reclaim path if memory pressure is heavy.  With
    that, we could avoid unnecessary THP split.
    
    For the feature, this patch changes pte dirtness marking logic of THP.
    Now, it marks every ptes of pages dirty unconditionally in splitting,
    which makes MADV_FREE void.  So, instead, this patch propagates pmd
    dirtiness to all pages via PG_dirty and restores pte dirtiness from
    PG_dirty.  With this, if pmd is clean(ie, MADV_FREEed) when split
    happens(e,g, shrink_page_list), all of pages are clean too so we could
    discard them.
    Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
    Cc: Kirill A. Shutemov <kirill@shutemov.name>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
    Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
    Cc: Shaohua Li <shli@kernel.org>
    Cc: <yalin.wang2010@gmail.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Chen Gang <gang.chen.5i5j@gmail.com>
    Cc: Chris Zankel <chris@zankel.net>
    Cc: Daniel Micay <danielmicay@gmail.com>
    Cc: Darrick J. Wong <darrick.wong@oracle.com>
    Cc: David S. Miller <davem@davemloft.net>
    Cc: Helge Deller <deller@gmx.de>
    Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
    Cc: Jason Evans <je@fb.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Cc: Matt Turner <mattst88@gmail.com>
    Cc: Max Filippov <jcmvbkbc@gmail.com>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Michael Kerrisk <mtk.manpages@gmail.com>
    Cc: Michal Hocko <mhocko@suse.com>
    Cc: Mika Penttil <mika.penttila@nextfour.com>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Cc: Richard Henderson <rth@twiddle.net>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Roland Dreier <roland@kernel.org>
    Cc: Russell King <rmk@arm.linux.org.uk>
    Cc: Shaohua Li <shli@kernel.org>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: Wu Fengguang <fengguang.wu@intel.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    b8d3c4c3
madvise.c 18.5 KB