• Mel Gorman's avatar
    mm: numa: Scan pages with elevated page_mapcount · 1bc115d8
    Mel Gorman authored
    Currently automatic NUMA balancing is unable to distinguish between false
    shared versus private pages except by ignoring pages with an elevated
    page_mapcount entirely. This avoids shared pages bouncing between the
    nodes whose task is using them but that is ignored quite a lot of data.
    
    This patch kicks away the training wheels in preparation for adding support
    for identifying shared/private pages is now in place. The ordering is so
    that the impact of the shared/private detection can be easily measured. Note
    that the patch does not migrate shared, file-backed within vmas marked
    VM_EXEC as these are generally shared library pages. Migrating such pages
    is not beneficial as there is an expectation they are read-shared between
    caches and iTLB and iCache pressure is generally low.
    Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
    Reviewed-by: default avatarRik van Riel <riel@redhat.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
    Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/r/1381141781-10992-28-git-send-email-mgorman@suse.deSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    1bc115d8
migrate.c 44.7 KB