Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751623AbaLEKV1 (ORCPT ); Fri, 5 Dec 2014 05:21:27 -0500 Received: from cnbjrel01.sonyericsson.com ([219.141.167.165]:5602 "EHLO cnbjrel01.sonyericsson.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750725AbaLEKV0 convert rfc822-to-8bit (ORCPT ); Fri, 5 Dec 2014 05:21:26 -0500 From: "Wang, Yalin" To: "'linux-kernel@vger.kernel.org'" , "'linux-mm@kvack.org'" , "'linux-arm-kernel@lists.infradead.org'" , "'Konstantin Khlebnikov'" , "'akpm@linux-foundation.org'" , "'n-horiguchi@ah.jp.nec.com'" , "'Konstantin Khlebnikov'" Date: Fri, 5 Dec 2014 18:21:17 +0800 Subject: [RFC V2] mm:add KPF_ZERO_PAGE flag for /proc/kpageflags Thread-Topic: [RFC V2] mm:add KPF_ZERO_PAGE flag for /proc/kpageflags Thread-Index: AdAQaYTRBP+XSfzeRTCVl77g86jARgACuLQw Message-ID: <35FD53F367049845BC99AC72306C23D103E688B313F1@CNBJMBX05.corpusers.net> References: <35FD53F367049845BC99AC72306C23D103E688B313EE@CNBJMBX05.corpusers.net> In-Reply-To: <35FD53F367049845BC99AC72306C23D103E688B313EE@CNBJMBX05.corpusers.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 #include #include +#include #include #include #include @@ -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; + } 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) { -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/