From 46c77e2bb07eba3b38edfec76873f12942c49dd3 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Tue, 12 Nov 2013 15:07:50 -0800 Subject: 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 Cc: Wu Fengguang Cc: Pavel Emelyanov Cc: Cyrill Gorcunov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel-page-flags.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') 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 */ -- cgit v1.2.3