From: Davidlohr Bueso <dave@stgolabs.net>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>, Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Rik van Riel <riel@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
Sasha Levin <sasha.levin@oracle.com>,
Andrey Konovalov <andreyknvl@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/12] mm: rmap use pte lock not mmap_sem to set PageMlocked
Date: Mon, 19 Oct 2015 16:30:22 -0700 [thread overview]
Message-ID: <20151019233022.GA27292@linux-uzut.site> (raw)
In-Reply-To: <20151019131308.GB15819@node.shutemov.name>
On Mon, 19 Oct 2015, Kirill A. Shutemov wrote:
>I think we need to have at lease WRITE_ONCE() everywhere we update
>vm_flags and READ_ONCE() where we read it without mmap_sem taken.
Given the CPU-CPU interaction, lockless/racy vm_flag checks should
actually be using barrier pairing, afaict. This is expensive obviously,
but I cannot recall what other places we do lockless games with vm_flags.
Perhaps its time to introduce formal helpers around vma->vm_flags such
that we can encapsulate such things: __vma_[set/read]_vmflags() or whatever
that would be used for those racy scenarios.
Thanks,
Davidlohr
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next prev parent reply other threads:[~2015-10-19 23:30 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 ` Davidlohr Bueso [this message]
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
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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