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author | Naoya Horiguchi | 2013-11-13 00:07:50 +0100 |
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committer | Linus Torvalds | 2013-11-13 04:09:07 +0100 |
commit | 46c77e2bb07eba3b38edfec76873f12942c49dd3 (patch) | |
tree | 2e6dd491627079f3e377e948f23137dd0c4cab40 /fs/sync.c | |
parent | /proc/pid/smaps: show VM_SOFTDIRTY flag in VmFlags line (diff) | |
download | kernel-qcow2-linux-46c77e2bb07eba3b38edfec76873f12942c49dd3.tar.gz kernel-qcow2-linux-46c77e2bb07eba3b38edfec76873f12942c49dd3.tar.xz kernel-qcow2-linux-46c77e2bb07eba3b38edfec76873f12942c49dd3.zip |
tools/vm/page-types.c: support KPF_SOFTDIRTY bit
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: Naoya 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/sync.c')
0 files changed, 0 insertions, 0 deletions