Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933499AbbELNfJ (ORCPT ); Tue, 12 May 2015 09:35:09 -0400 Received: from mx2.parallels.com ([199.115.105.18]:59638 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933156AbbELNe7 (ORCPT ); Tue, 12 May 2015 09:34:59 -0400 From: Vladimir Davydov To: Andrew Morton CC: Minchan Kim , Johannes Weiner , Michal Hocko , Greg Thelen , Michel Lespinasse , David Rientjes , Pavel Emelyanov , Cyrill Gorcunov , Jonathan Corbet , , , , , Subject: [PATCH v5 4/4] proc: export idle flag via kpageflags Date: Tue, 12 May 2015 16:34:19 +0300 Message-ID: <76ae306c6b6fc65ef5538e7b5771b6ca4104db00.1431437088.git.vdavydov@parallels.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2694 Lines: 75 As noted by Minchan, a benefit of reading idle flag from /proc/kpageflags is that one can easily filter dirty and/or unevictable pages while estimating the size of unused memory. Note that idle flag read from /proc/kpageflags may be stale in case the page was accessed via a PTE, because it would be too costly to iterate over all page mappings on each /proc/kpageflags read to provide an up-to-date value. To make sure the flag is up-to-date one has to read /proc/kpageidle first. Signed-off-by: Vladimir Davydov --- Documentation/vm/pagemap.txt | 6 ++++++ fs/proc/page.c | 3 +++ include/uapi/linux/kernel-page-flags.h | 1 + 3 files changed, 10 insertions(+) diff --git a/Documentation/vm/pagemap.txt b/Documentation/vm/pagemap.txt index c9266340852c..5896b7d7fd74 100644 --- a/Documentation/vm/pagemap.txt +++ b/Documentation/vm/pagemap.txt @@ -64,6 +64,7 @@ There are five components to pagemap: 22. THP 23. BALLOON 24. ZERO_PAGE + 25. IDLE * /proc/kpagecgroup. This file contains a 64-bit inode number of the memory cgroup each page is charged to, indexed by PFN. Only available when @@ -124,6 +125,11 @@ Short descriptions to the page flags: 24. ZERO_PAGE zero page for pfn_zero or huge_zero page +25. IDLE + page has not been accessed since it was marked idle (see /proc/kpageidle) + Note that this flag may be stale in case the page was accessed via a PTE. + To make sure the flag is up-to-date one has to read /proc/kpageidle first. + [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 f42ead08d346..24748be3dd65 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -148,6 +148,9 @@ u64 stable_page_flags(struct page *page) if (PageBalloon(page)) u |= 1 << KPF_BALLOON; + if (page_is_idle(page)) + u |= 1 << KPF_IDLE; + u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked); u |= kpf_copy_bit(k, KPF_SLAB, PG_slab); diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h index a6c4962e5d46..5da5f8751ce7 100644 --- a/include/uapi/linux/kernel-page-flags.h +++ b/include/uapi/linux/kernel-page-flags.h @@ -33,6 +33,7 @@ #define KPF_THP 22 #define KPF_BALLOON 23 #define KPF_ZERO_PAGE 24 +#define KPF_IDLE 25 #endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */ -- 1.7.10.4 -- 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/