The patch titled
Subject: mm:add KPF_ZERO_PAGE flag for /proc/kpageflags
has been added to the -mm tree. Its filename is
mm-add-kpf_zero_page-flag-for-proc-kpageflags.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-add-kpf_zero_page-flag-for-proc-kpageflags.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-add-kpf_zero_page-flag-for-proc-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: "Wang, Yalin" <Yalin.Wang@xxxxxxxxxxxxxx>
Subject: mm:add KPF_ZERO_PAGE flag for /proc/kpageflags
Add KPF_ZERO_PAGE flag for zero_page, so that userspace processes can
detect zero_page in /proc/kpageflags, and then do memory analysis more
accurately.
Signed-off-by: Yalin Wang <yalin.wang@xxxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/pagemap.txt | 8 ++++++++
fs/proc/page.c | 16 +++++++++++++---
include/linux/huge_mm.h | 12 ++++++++++++
include/uapi/linux/kernel-page-flags.h | 1 +
mm/huge_memory.c | 7 +------
tools/vm/page-types.c | 1 +
6 files changed, 36 insertions(+), 9 deletions(-)
diff -puN Documentation/vm/pagemap.txt~mm-add-kpf_zero_page-flag-for-proc-kpageflags Documentation/vm/pagemap.txt
--- a/Documentation/vm/pagemap.txt~mm-add-kpf_zero_page-flag-for-proc-kpageflags
+++ a/Documentation/vm/pagemap.txt
@@ -62,6 +62,8 @@ There are three components to pagemap:
20. NOPAGE
21. KSM
22. THP
+ 23. BALLOON
+ 24. ZERO_PAGE
Short descriptions to the page flags:
@@ -102,6 +104,12 @@ Short descriptions to the page flags:
22. THP
contiguous pages which construct transparent hugepages
+23. BALLOON
+ balloon compaction page
+
+24. ZERO_PAGE
+ zero page for pfn_zero or huge_zero page
+
[IO related page flags]
1. ERROR IO error occurred
3. UPTODATE page has up-to-date data
diff -puN fs/proc/page.c~mm-add-kpf_zero_page-flag-for-proc-kpageflags fs/proc/page.c
--- a/fs/proc/page.c~mm-add-kpf_zero_page-flag-for-proc-kpageflags
+++ a/fs/proc/page.c
@@ -5,6 +5,7 @@
#include <linux/ksm.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
+#include <linux/huge_mm.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/hugetlb.h>
@@ -121,9 +122,18 @@ u64 stable_page_flags(struct page *page)
* just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
* to make sure a given page is a thp, not a non-huge compound page.
*/
- else if (PageTransCompound(page) && (PageLRU(compound_head(page)) ||
- PageAnon(compound_head(page))))
- u |= 1 << KPF_THP;
+ else if (PageTransCompound(page)) {
+ struct page *head = compound_head(page);
+
+ if (PageLRU(head) || PageAnon(head))
+ u |= 1 << KPF_THP;
+ else if (is_huge_zero_page(head)) {
+ u |= 1 << KPF_ZERO_PAGE;
+ u |= 1 << KPF_THP;
+ }
+ } else if (is_zero_pfn(page_to_pfn(page)))
+ u |= 1 << KPF_ZERO_PAGE;
+
/*
* Caveats on high order pages: page->_count will only be set
diff -puN include/linux/huge_mm.h~mm-add-kpf_zero_page-flag-for-proc-kpageflags include/linux/huge_mm.h
--- a/include/linux/huge_mm.h~mm-add-kpf_zero_page-flag-for-proc-kpageflags
+++ a/include/linux/huge_mm.h
@@ -157,6 +157,13 @@ static inline int hpage_nr_pages(struct
extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, pmd_t *pmdp);
+extern struct page *huge_zero_page;
+
+static inline bool is_huge_zero_page(struct page *page)
+{
+ return ACCESS_ONCE(huge_zero_page) == page;
+}
+
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
@@ -206,6 +213,11 @@ static inline int do_huge_pmd_numa_page(
return 0;
}
+static inline bool is_huge_zero_page(struct page *page)
+{
+ return false;
+}
+
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif /* _LINUX_HUGE_MM_H */
diff -puN include/uapi/linux/kernel-page-flags.h~mm-add-kpf_zero_page-flag-for-proc-kpageflags include/uapi/linux/kernel-page-flags.h
--- a/include/uapi/linux/kernel-page-flags.h~mm-add-kpf_zero_page-flag-for-proc-kpageflags
+++ a/include/uapi/linux/kernel-page-flags.h
@@ -32,6 +32,7 @@
#define KPF_KSM 21
#define KPF_THP 22
#define KPF_BALLOON 23
+#define KPF_ZERO_PAGE 24
#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
diff -puN mm/huge_memory.c~mm-add-kpf_zero_page-flag-for-proc-kpageflags mm/huge_memory.c
--- a/mm/huge_memory.c~mm-add-kpf_zero_page-flag-for-proc-kpageflags
+++ a/mm/huge_memory.c
@@ -171,12 +171,7 @@ static int start_khugepaged(void)
}
static atomic_t huge_zero_refcount;
-static struct page *huge_zero_page __read_mostly;
-
-static inline bool is_huge_zero_page(struct page *page)
-{
- return ACCESS_ONCE(huge_zero_page) == page;
-}
+struct page *huge_zero_page __read_mostly;
static inline bool is_huge_zero_pmd(pmd_t pmd)
{
diff -puN tools/vm/page-types.c~mm-add-kpf_zero_page-flag-for-proc-kpageflags tools/vm/page-types.c
--- a/tools/vm/page-types.c~mm-add-kpf_zero_page-flag-for-proc-kpageflags
+++ a/tools/vm/page-types.c
@@ -133,6 +133,7 @@ static const char * const page_flag_name
[KPF_KSM] = "x:ksm",
[KPF_THP] = "t:thp",
[KPF_BALLOON] = "o:balloon",
+ [KPF_ZERO_PAGE] = "z:zero_page",
[KPF_RESERVED] = "r:reserved",
[KPF_MLOCKED] = "m:mlocked",
_
Patches currently in -mm which might be from Yalin.Wang@xxxxxxxxxxxxxx are
origin.patch
mm-add-vm_bug_on_page-for-page_mapcount.patch
mm-add-kpf_zero_page-flag-for-proc-kpageflags.patch
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