• Naoya Horiguchi's avatar
    tools/vm/page-types.c: support KPF_SOFTDIRTY bit · 46c77e2b
    Naoya Horiguchi authored
    Soft dirty bit allows us to track which pages are written since the last
    clear_ref (by "echo 4 > /proc/pid/clear_refs".) This is useful for
    userspace applications to know their memory footprints.
    Note that the kernel exposes this flag via bit[55] of /proc/pid/pagemap,
    and the semantics is not a default one (scheduled to be the default in the
    near future.) However, it shifts to the new semantics at the first
    clear_ref, and the users of soft dirty bit always do it before utilizing
    the bit, so that's not a big deal.  Users must avoid relying on the bit in
    page-types before the first clear_ref.
    Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Cc: Wu Fengguang <fengguang.wu@intel.com>
    Cc: Pavel Emelyanov <xemul@parallels.com>
    Cc: Cyrill Gorcunov <gorcunov@openvz.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
kernel-page-flags.h 466 Bytes