46c77e2bb0
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>
21 lines
466 B
C
21 lines
466 B
C
#ifndef LINUX_KERNEL_PAGE_FLAGS_H
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#define LINUX_KERNEL_PAGE_FLAGS_H
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#include <uapi/linux/kernel-page-flags.h>
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/* kernel hacking assistances
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* WARNING: subject to change, never rely on them!
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*/
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#define KPF_RESERVED 32
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#define KPF_MLOCKED 33
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#define KPF_MAPPEDTODISK 34
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#define KPF_PRIVATE 35
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#define KPF_PRIVATE_2 36
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#define KPF_OWNER_PRIVATE 37
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#define KPF_ARCH 38
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#define KPF_UNCACHED 39
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#define KPF_SOFTDIRTY 40
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#endif /* LINUX_KERNEL_PAGE_FLAGS_H */
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