• Leonid Yegoshin's avatar
    mm compaction: fix of improper cache flush in migration code · c2cc499c
    Leonid Yegoshin authored
    Page 'new' during MIGRATION can't be flushed with flush_cache_page().
    Using flush_cache_page(vma, addr, pfn) is justified only if the page is
    already placed in process page table, and that is done right after
    flush_cache_page().  But without it the arch function has no knowledge
    of process PTE and does nothing.
    Besides that, flush_cache_page() flushes an application cache page, but
    the kernel has a different page virtual address and dirtied it.
    Replace it with flush_dcache_page(new) which is the proper usage.
    The old page is flushed in try_to_unmap_one() before migration.
    This bug takes place in Sead3 board with M14Kc MIPS CPU without cache
    aliasing (but Harvard arch - separate I and D cache) in tight memory
    environment (128MB) each 1-3days on SOAK test.  It fails in cc1 during
    kernel build (SIGILL, SIGBUS, SIGSEG) if CONFIG_COMPACTION is switched
    Signed-off-by: default avatarLeonid Yegoshin <Leonid.Yegoshin@imgtec.com>
    Cc: Leonid Yegoshin <yegoshin@mips.com>
    Acked-by: default avatarRik van Riel <riel@redhat.com>
    Cc: Michal Hocko <mhocko@suse.cz>
    Acked-by: default avatarMel Gorman <mgorman@suse.de>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Cc: Russell King <rmk@arm.linux.org.uk>
    Cc: David Miller <davem@davemloft.net>
    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>
migrate.c 44 KB