• W
    mm: hugetlb: add arch hook for clearing page flags before entering pool · 5d3a551c
    Will Deacon 提交于
    The core page allocator ensures that page flags are zeroed when freeing
    pages via free_pages_check.  A number of architectures (ARM, PPC, MIPS)
    rely on this property to treat new pages as dirty with respect to the data
    cache and perform the appropriate flushing before mapping the pages into
    userspace.
    
    This can lead to cache synchronisation problems when using hugepages,
    since the allocator keeps its own pool of pages above the usual page
    allocator and does not reset the page flags when freeing a page into the
    pool.
    
    This patch adds a new architecture hook, arch_clear_hugepage_flags, so
    that architectures which rely on the page flags being in a particular
    state for fresh allocations can adjust the flags accordingly when a page
    is freed into the pool.
    Signed-off-by: NWill Deacon <will.deacon@arm.com>
    Cc: Michal Hocko <mhocko@suse.cz>
    Reviewed-by: NMichal Hocko <mhocko@suse.cz>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    5d3a551c
hugetlb.h 2.1 KB