The patch titled
Subject: proc: export idle flag via kpageflags
has been added to the -mm tree. Its filename is
proc-export-idle-flag-via-kpageflags.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-export-idle-flag-via-kpageflags.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-export-idle-flag-via-kpageflags.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Subject: proc: export idle flag via kpageflags
As noted by Minchan, a benefit of reading idle flag from /proc/kpageflags
is that one can easily filter dirty and/or unevictable pages while
estimating the size of unused memory.
Note that idle flag read from /proc/kpageflags may be stale in case the
page was accessed via a PTE, because it would be too costly to iterate
over all page mappings on each /proc/kpageflags read to provide an
up-to-date value. To make sure the flag is up-to-date one has to read
/proc/kpageidle first.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Reviewed-by: Andres Lagar-Cavilla <andreslc@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/pagemap.txt | 6 ++++++
fs/proc/page.c | 3 +++
include/uapi/linux/kernel-page-flags.h | 1 +
3 files changed, 10 insertions(+)
diff -puN Documentation/vm/pagemap.txt~proc-export-idle-flag-via-kpageflags Documentation/vm/pagemap.txt
--- a/Documentation/vm/pagemap.txt~proc-export-idle-flag-via-kpageflags
+++ a/Documentation/vm/pagemap.txt
@@ -70,6 +70,7 @@ There are five components to pagemap:
22. THP
23. BALLOON
24. ZERO_PAGE
+ 25. IDLE
* /proc/kpagecgroup. This file contains a 64-bit inode number of the
memory cgroup each page is charged to, indexed by PFN. Only available when
@@ -130,6 +131,11 @@ Short descriptions to the page flags:
24. ZERO_PAGE
zero page for pfn_zero or huge_zero page
+25. IDLE
+ page has not been accessed since it was marked idle (see /proc/kpageidle)
+ Note that this flag may be stale in case the page was accessed via a PTE.
+ To make sure the flag is up-to-date one has to read /proc/kpageidle first.
+
[IO related page flags]
1. ERROR IO error occurred
3. UPTODATE page has up-to-date data
diff -puN fs/proc/page.c~proc-export-idle-flag-via-kpageflags fs/proc/page.c
--- a/fs/proc/page.c~proc-export-idle-flag-via-kpageflags
+++ a/fs/proc/page.c
@@ -150,6 +150,9 @@ u64 stable_page_flags(struct page *page)
if (PageBalloon(page))
u |= 1 << KPF_BALLOON;
+ if (page_is_idle(page))
+ u |= 1 << KPF_IDLE;
+
u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
diff -puN include/uapi/linux/kernel-page-flags.h~proc-export-idle-flag-via-kpageflags include/uapi/linux/kernel-page-flags.h
--- a/include/uapi/linux/kernel-page-flags.h~proc-export-idle-flag-via-kpageflags
+++ a/include/uapi/linux/kernel-page-flags.h
@@ -33,6 +33,7 @@
#define KPF_THP 22
#define KPF_BALLOON 23
#define KPF_ZERO_PAGE 24
+#define KPF_IDLE 25
#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
_
Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are
memcg-export-struct-mem_cgroup.patch
memcg-export-struct-mem_cgroup-fix.patch
memcg-export-struct-mem_cgroup-fix-2.patch
memcg-get-rid-of-mem_cgroup_root_css-for-config_memcg.patch
memcg-get-rid-of-extern-for-functions-in-memcontrolh.patch
memcg-restructure-mem_cgroup_can_attach.patch
memcg-tcp_kmem-check-for-cg_proto-in-sock_update_memcg.patch
memcg-add-page_cgroup_ino-helper.patch
hwpoison-use-page_cgroup_ino-for-filtering-by-memcg.patch
memcg-zap-try_get_mem_cgroup_from_page.patch
proc-add-kpagecgroup-file.patch
mmu-notifier-add-clear_young-callback.patch
proc-add-kpageidle-file.patch
proc-export-idle-flag-via-kpageflags.patch
proc-add-cond_resched-to-proc-kpage-read-write-loop.patch
mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated.patch
mm-swap-zswap-maybe_preload-refactoring.patch
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