Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932510AbaLJRGM (ORCPT ); Wed, 10 Dec 2014 12:06:12 -0500 Received: from mail-wg0-f53.google.com ([74.125.82.53]:33658 "EHLO mail-wg0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754895AbaLJRGL (ORCPT ); Wed, 10 Dec 2014 12:06:11 -0500 MIME-Version: 1.0 In-Reply-To: <35FD53F367049845BC99AC72306C23D103E688B313FB@CNBJMBX05.corpusers.net> References: <35FD53F367049845BC99AC72306C23D103E688B313EE@CNBJMBX05.corpusers.net> <35FD53F367049845BC99AC72306C23D103E688B313F2@CNBJMBX05.corpusers.net> <20141205143134.37139da2208c654a0d3cd942@linux-foundation.org> <35FD53F367049845BC99AC72306C23D103E688B313F4@CNBJMBX05.corpusers.net> <20141208114601.GA28846@node.dhcp.inet.fi> <35FD53F367049845BC99AC72306C23D103E688B313FB@CNBJMBX05.corpusers.net> Date: Wed, 10 Dec 2014 21:06:05 +0400 Message-ID: Subject: Re: [RFC V5] mm:add KPF_ZERO_PAGE flag for /proc/kpageflags From: Konstantin Khlebnikov To: "Wang, Yalin" Cc: "Kirill A. Shutemov" , Andrew Morton , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-arm-kernel@lists.infradead.org" , "n-horiguchi@ah.jp.nec.com" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 9, 2014 at 6:24 AM, 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 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 > #include > #include > +#include > #include > #include > #include > @@ -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 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/