On Fri, Dec 05, 2014 at 06:21:17PM +0800, Wang, Yalin 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>
> ---
> fs/proc/page.c | 14 +++++++++++---
> include/linux/huge_mm.h | 12 ++++++++++++
> include/uapi/linux/kernel-page-flags.h | 1 +
> mm/huge_memory.c | 7 +------
> 4 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/fs/proc/page.c b/fs/proc/page.c
> index 1e3187d..dbe5630 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 +122,16 @@ 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;
IIUC, KPF_THP bit should be set for huge zero page too.
--
Kirill A. Shutemov
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