kpageflags-zero-huge-page
From: Konstantin Khebnikov <khlebnikov@yandex-team.ru>
---
fs/proc/page.c | 12 +++++++++---
include/linux/huge_mm.h | 12 ++++++++++++
mm/huge_memory.c | 7 +------
3 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 1e3187d..cad5cd4 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 +122,14 @@ 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;
+ }
/*
* 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/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)
{