On Tue, Dec 9, 2014 at 6:24 AM, Wang, Yalin <Yalin.Wang@xxxxxxxxxxxxxx> wrote: > This patch add KPF_ZERO_PAGE flag for zero_page, > so that userspace process can notice zero_page from > /proc/kpageflags, and then do memory analysis more accurately. > > Signed-off-by: Yalin Wang <yalin.wang@xxxxxxxxxxxxxx> Ack. Looks good. > --- > 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 --git a/Documentation/vm/pagemap.txt b/Documentation/vm/pagemap.txt > index 5948e45..6fbd55e 100644 > --- a/Documentation/vm/pagemap.txt > +++ b/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 --git a/fs/proc/page.c b/fs/proc/page.c > index 1e3187d..7eee2d8 100644 > --- a/fs/proc/page.c > +++ b/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 --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index ad9051b..f10b20f 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -157,6 +157,13 @@ static inline int hpage_nr_pages(struct page *page) > 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(struct mm_struct *mm, struct vm_area_str > return 0; > } > > +static inline bool is_huge_zero_page(struct page *page) > +{ > + return false; > +} > + > #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > > #endif /* _LINUX_HUGE_MM_H */ > diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h > index 2f96d23..a6c4962 100644 > --- a/include/uapi/linux/kernel-page-flags.h > +++ b/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 --git a/mm/huge_memory.c b/mm/huge_memory.c > index de98415..d7bc7a5 100644 > --- a/mm/huge_memory.c > +++ b/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 --git a/tools/vm/page-types.c b/tools/vm/page-types.c > index 264fbc2..8bdf16b 100644 > --- a/tools/vm/page-types.c > +++ b/tools/vm/page-types.c > @@ -133,6 +133,7 @@ static const char * const page_flag_names[] = { > [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", > -- > 2.1.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>