From: Minchan Kim <minchan@kernel.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael Kerrisk <mtk.manpages@gmail.com>, linux-api@vger.kernel.org, Hugh Dickins <hughd@google.com>, Johannes Weiner <hannes@cmpxchg.org>, zhangyanfei@cn.fujitsu.com, Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Jason Evans <je@fb.com>, Daniel Micay <danielmicay@gmail.com>, "Kirill A. Shutemov" <kirill@shutemov.name>, Michal Hocko <mhocko@suse.cz>, yalin.wang2010@gmail.com, Shaohua Li <shli@kernel.org>, Minchan Kim <minchan@kernel.org> Subject: [PATCH 8/8] mm: mark stable page dirty in KSM Date: Fri, 30 Oct 2015 16:01:44 +0900 [thread overview] Message-ID: <1446188504-28023-9-git-send-email-minchan@kernel.org> (raw) In-Reply-To: <1446188504-28023-1-git-send-email-minchan@kernel.org> The MADV_FREE patchset changes page reclaim to simply free a clean anonymous page with no dirty ptes, instead of swapping it out; but KSM uses clean write-protected ptes to reference the stable ksm page. So be sure to mark that page dirty, so it's never mistakenly discarded. [hughd: adjusted comments] Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Minchan Kim <minchan@kernel.org> --- mm/ksm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/ksm.c b/mm/ksm.c index 7ee101eaacdf..18d2b7afecff 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1053,6 +1053,12 @@ static int try_to_merge_one_page(struct vm_area_struct *vma, */ set_page_stable_node(page, NULL); mark_page_accessed(page); + /* + * Page reclaim just frees a clean page with no dirty + * ptes: make sure that the ksm page would be swapped. + */ + if (!PageDirty(page)) + SetPageDirty(page); err = 0; } else if (pages_identical(page, kpage)) err = replace_page(vma, page, kpage, orig_pte); -- 1.9.1
WARNING: multiple messages have this Message-ID (diff)
From: Minchan Kim <minchan@kernel.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael Kerrisk <mtk.manpages@gmail.com>, linux-api@vger.kernel.org, Hugh Dickins <hughd@google.com>, Johannes Weiner <hannes@cmpxchg.org>, zhangyanfei@cn.fujitsu.com, Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Jason Evans <je@fb.com>, Daniel Micay <danielmicay@gmail.com>, "Kirill A. Shutemov" <kirill@shutemov.name>, Michal Hocko <mhocko@suse.cz>, yalin.wang2010@gmail.com, Shaohua Li <shli@kernel.org>, Minchan Kim <minchan@kernel.org> Subject: [PATCH 8/8] mm: mark stable page dirty in KSM Date: Fri, 30 Oct 2015 16:01:44 +0900 [thread overview] Message-ID: <1446188504-28023-9-git-send-email-minchan@kernel.org> (raw) In-Reply-To: <1446188504-28023-1-git-send-email-minchan@kernel.org> The MADV_FREE patchset changes page reclaim to simply free a clean anonymous page with no dirty ptes, instead of swapping it out; but KSM uses clean write-protected ptes to reference the stable ksm page. So be sure to mark that page dirty, so it's never mistakenly discarded. [hughd: adjusted comments] Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Minchan Kim <minchan@kernel.org> --- mm/ksm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/ksm.c b/mm/ksm.c index 7ee101eaacdf..18d2b7afecff 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1053,6 +1053,12 @@ static int try_to_merge_one_page(struct vm_area_struct *vma, */ set_page_stable_node(page, NULL); mark_page_accessed(page); + /* + * Page reclaim just frees a clean page with no dirty + * ptes: make sure that the ksm page would be swapped. + */ + if (!PageDirty(page)) + SetPageDirty(page); err = 0; } else if (pages_identical(page, kpage)) err = replace_page(vma, page, kpage, orig_pte); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-10-30 7:01 UTC|newest] Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-10-30 7:01 [PATCH 0/8] MADV_FREE support Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 7:01 ` [PATCH 1/8] mm: support madvise(MADV_FREE) Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 16:49 ` Shaohua Li 2015-10-30 16:49 ` Shaohua Li 2015-11-03 0:10 ` Minchan Kim 2015-11-03 0:10 ` Minchan Kim 2015-11-03 0:10 ` Minchan Kim 2015-10-30 7:01 ` [PATCH 2/8] mm: define MADV_FREE for some arches Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 7:01 ` [PATCH 3/8] arch: uapi: asm: mman.h: Let MADV_FREE have same value for all architectures Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-11-02 0:08 ` Hugh Dickins 2015-11-02 0:08 ` Hugh Dickins 2015-11-02 0:08 ` Hugh Dickins 2015-11-02 0:08 ` Hugh Dickins 2015-11-03 2:32 ` Minchan Kim 2015-11-03 2:32 ` Minchan Kim 2015-11-03 2:32 ` Minchan Kim 2015-11-03 2:32 ` Minchan Kim 2015-11-03 2:36 ` Minchan Kim 2015-11-03 2:36 ` Minchan Kim 2015-11-03 2:36 ` Minchan Kim 2015-11-03 2:36 ` Minchan Kim 2015-11-03 3:36 ` David Miller 2015-11-03 3:36 ` David Miller 2015-11-03 3:36 ` David Miller 2015-11-03 4:31 ` Minchan Kim 2015-11-03 4:31 ` Minchan Kim 2015-11-03 4:31 ` Minchan Kim 2015-10-30 7:01 ` [PATCH 4/8] mm: free swp_entry in madvise_free Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 12:28 ` Michal Hocko 2015-10-30 12:28 ` Michal Hocko 2015-11-03 0:53 ` Minchan Kim 2015-11-03 0:53 ` Minchan Kim 2015-11-03 0:53 ` Minchan Kim 2015-10-30 7:01 ` [PATCH 5/8] mm: move lazily freed pages to inactive list Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 17:22 ` Shaohua Li 2015-10-30 17:22 ` Shaohua Li 2015-10-30 17:22 ` Shaohua Li 2015-11-03 0:52 ` Minchan Kim 2015-11-03 0:52 ` Minchan Kim 2015-11-03 0:52 ` Minchan Kim 2015-11-04 8:15 ` Michal Hocko 2015-11-04 8:15 ` Michal Hocko 2015-11-04 17:53 ` Shaohua Li 2015-11-04 17:53 ` Shaohua Li 2015-11-04 17:53 ` Shaohua Li 2015-11-04 18:20 ` Shaohua Li 2015-11-04 18:20 ` Shaohua Li 2015-11-05 1:11 ` Minchan Kim 2015-11-05 1:11 ` Minchan Kim 2015-11-05 1:03 ` Minchan Kim 2015-11-05 1:03 ` Minchan Kim 2015-11-05 1:03 ` Minchan Kim 2015-11-04 20:55 ` Johannes Weiner 2015-11-04 20:55 ` Johannes Weiner 2015-11-04 20:55 ` Johannes Weiner 2015-11-04 21:48 ` Daniel Micay 2015-11-04 21:48 ` Daniel Micay 2015-11-04 22:55 ` Johannes Weiner 2015-11-04 22:55 ` Johannes Weiner 2015-11-04 22:55 ` Johannes Weiner 2015-11-04 23:36 ` Daniel Micay 2015-11-04 23:49 ` Daniel Micay 2015-11-04 23:49 ` Daniel Micay 2015-10-30 7:01 ` [PATCH 6/8] mm: lru_deactivate_fn should clear PG_referenced Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 12:47 ` Michal Hocko 2015-10-30 12:47 ` Michal Hocko 2015-10-30 12:47 ` Michal Hocko 2015-11-03 1:10 ` Minchan Kim 2015-11-03 1:10 ` Minchan Kim 2015-11-04 8:22 ` Michal Hocko 2015-11-04 8:22 ` Michal Hocko 2015-11-04 8:22 ` Michal Hocko 2015-10-30 7:01 ` [PATCH 7/8] mm: clear PG_dirty to mark page freeable Minchan Kim 2015-10-30 7:01 ` Minchan Kim 2015-10-30 12:55 ` Michal Hocko 2015-10-30 12:55 ` Michal Hocko 2015-10-30 12:55 ` Michal Hocko 2015-10-30 7:01 ` Minchan Kim [this message] 2015-10-30 7:01 ` [PATCH 8/8] mm: mark stable page dirty in KSM Minchan Kim 2015-11-01 4:51 ` [PATCH 0/8] MADV_FREE support David Rientjes 2015-11-01 4:51 ` David Rientjes 2015-11-01 4:51 ` David Rientjes 2015-11-01 6:29 ` Daniel Micay 2015-11-03 2:23 ` Minchan Kim 2015-11-03 2:23 ` Minchan Kim 2015-11-03 2:23 ` Minchan Kim 2015-11-04 20:19 ` David Rientjes 2015-11-04 20:19 ` David Rientjes
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