From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Mel Gorman <mgorman@techsingularity.net>,
Minchan Kim <minchan@kernel.org>,
Pavel Emelyanov <xemul@parallels.com>,
linux-mm@kvack.org
Subject: Re: [PATCH 10/12] mm: page migration use migration entry for swapcache too
Date: Fri, 23 Oct 2015 01:35:59 +0300 [thread overview]
Message-ID: <20151022223558.GT2080@uranus> (raw)
In-Reply-To: <alpine.LSU.2.11.1510182203200.2481@eggly.anvils>
On Sun, Oct 18, 2015 at 10:05:28PM -0700, Hugh Dickins wrote:
> Hitherto page migration has avoided using a migration entry for a
> swapcache page mapped into userspace, apparently for historical reasons.
> So any page blessed with swapcache would entail a minor fault when it's
> next touched, which page migration otherwise tries to avoid. Swapcache
> in an mlocked area is rare, so won't often matter, but still better fixed.
>
> Just rearrange the block in try_to_unmap_one(), to handle TTU_MIGRATION
> before checking PageAnon, that's all (apart from some reindenting).
>
> Well, no, that's not quite all: doesn't this by the way fix a soft_dirty
> bug, that page migration of a file page was forgetting to transfer the
> soft_dirty bit? Probably not a serious bug: if I understand correctly,
> soft_dirty afficionados usually have to handle file pages separately
> anyway; but we publish the bit in /proc/<pid>/pagemap on file mappings
> as well as anonymous, so page migration ought not to perturb it.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
Sorry for delay in response. Indeed this should fix the nit, thanks!
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
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next prev parent reply other threads:[~2015-10-22 22:36 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-19 4:44 [PATCH 0/12] mm: page migration cleanups, and a little mlock Hugh Dickins
2015-10-19 4:45 ` [PATCH 1/12] mm Documentation: undoc non-linear vmas Hugh Dickins
2015-10-19 9:16 ` Kirill A. Shutemov
2015-11-05 17:29 ` Vlastimil Babka
2015-10-19 4:50 ` [PATCH 2/12] mm: rmap use pte lock not mmap_sem to set PageMlocked Hugh Dickins
2015-10-19 6:23 ` Vlastimil Babka
2015-10-19 11:20 ` Hugh Dickins
2015-10-19 12:33 ` Vlastimil Babka
2015-10-19 19:17 ` Hugh Dickins
2015-10-19 20:52 ` Vlastimil Babka
2015-10-19 13:13 ` Kirill A. Shutemov
2015-10-19 19:53 ` Hugh Dickins
2015-10-19 20:10 ` Kirill A. Shutemov
2015-10-19 21:25 ` Vlastimil Babka
2015-10-19 21:53 ` Kirill A. Shutemov
2015-10-21 23:26 ` Hugh Dickins
2015-10-29 18:49 ` [PATCH v2 " Hugh Dickins
2015-11-05 17:50 ` Vlastimil Babka
2015-10-19 23:30 ` [PATCH " Davidlohr Bueso
2015-10-19 4:52 ` [PATCH 3/12] mm: page migration fix PageMlocked on migrated pages Hugh Dickins
2015-11-05 18:18 ` Vlastimil Babka
2015-10-19 4:54 ` [PATCH 4/12] mm: rename mem_cgroup_migrate to mem_cgroup_replace_page Hugh Dickins
2015-10-19 12:35 ` Johannes Weiner
2015-12-02 9:33 ` [PATCH] mm: fix kerneldoc on mem_cgroup_replace_page Hugh Dickins
2015-12-02 10:17 ` Michal Hocko
2015-12-02 16:57 ` Johannes Weiner
2015-10-19 4:55 ` [PATCH 5/12] mm: correct a couple of page migration comments Hugh Dickins
2015-10-21 17:53 ` Rafael Aquini
2015-10-19 4:57 ` [PATCH 6/12] mm: page migration use the put_new_page whenever necessary Hugh Dickins
2015-11-05 18:31 ` Vlastimil Babka
2015-11-08 21:17 ` Hugh Dickins
2015-10-19 4:59 ` [PATCH 7/12] mm: page migration trylock newpage at same level as oldpage Hugh Dickins
2015-10-21 17:54 ` Rafael Aquini
2015-10-19 5:01 ` [PATCH 8/12] mm: page migration remove_migration_ptes at lock+unlock level Hugh Dickins
2015-10-19 5:03 ` [PATCH 9/12] mm: simplify page migration's anon_vma comment and flow Hugh Dickins
2015-10-19 5:05 ` [PATCH 10/12] mm: page migration use migration entry for swapcache too Hugh Dickins
2015-10-22 22:35 ` Cyrill Gorcunov [this message]
2015-10-19 5:07 ` [PATCH 11/12] mm: page migration avoid touching newpage until no going back Hugh Dickins
2015-10-19 5:11 ` [PATCH 12/12] mm: migrate dirty page without clear_page_dirty_for_io etc Hugh Dickins
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