diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2013-11-05 16:55:43 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2013-11-05 16:55:43 +1100 |
| commit | e66f9af1178361120dab318bf6f2a7c44aabe5c7 (patch) | |
| tree | cee9542a27c5051f459be6222082773bcf1b4a85 /include | |
| parent | 60853928ace01cbd592275b77eb06a4b509df00a (diff) | |
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kernel-page-flags.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/kernel-page-flags.h b/include/linux/kernel-page-flags.h index 546eb6a76934..f65ce09784f1 100644 --- a/include/linux/kernel-page-flags.h +++ b/include/linux/kernel-page-flags.h @@ -15,5 +15,6 @@ #define KPF_OWNER_PRIVATE 37 #define KPF_ARCH 38 #define KPF_UNCACHED 39 +#define KPF_SOFTDIRTY 40 #endif /* LINUX_KERNEL_PAGE_FLAGS_H */ |