From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mel Gorman <mgorman@suse.de>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] THP: Use explicit memory barrier
Date: Mon, 01 Apr 2013 10:01:49 +0900 [thread overview]
Message-ID: <5158DC7D.2040607@jp.fujitsu.com> (raw)
In-Reply-To: <1364773535-26264-1-git-send-email-minchan@kernel.org>
(2013/04/01 8:45), Minchan Kim wrote:
> __do_huge_pmd_anonymous_page depends on page_add_new_anon_rmap's
> spinlock for making sure that clear_huge_page write become visible
> after set set_pmd_at() write.
>
> But lru_cache_add_lru uses pagevec so it could miss spinlock
> easily so above rule was broken so user may see inconsistent data.
> This patch fixes it with using explict barrier rather than depending
> on lru spinlock.
>
Hmm...how about do_anonymous_page() ? there are no comments/locks/barriers.
Users can see non-zero value after page fault in theory ?
Thanks,
-Kame
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WARNING: multiple messages have this Message-ID (diff)
From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mel Gorman <mgorman@suse.de>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] THP: Use explicit memory barrier
Date: Mon, 01 Apr 2013 10:01:49 +0900 [thread overview]
Message-ID: <5158DC7D.2040607@jp.fujitsu.com> (raw)
In-Reply-To: <1364773535-26264-1-git-send-email-minchan@kernel.org>
(2013/04/01 8:45), Minchan Kim wrote:
> __do_huge_pmd_anonymous_page depends on page_add_new_anon_rmap's
> spinlock for making sure that clear_huge_page write become visible
> after set set_pmd_at() write.
>
> But lru_cache_add_lru uses pagevec so it could miss spinlock
> easily so above rule was broken so user may see inconsistent data.
> This patch fixes it with using explict barrier rather than depending
> on lru spinlock.
>
Hmm...how about do_anonymous_page() ? there are no comments/locks/barriers.
Users can see non-zero value after page fault in theory ?
Thanks,
-Kame
next prev parent reply other threads:[~2013-04-01 1:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-31 23:45 [PATCH] THP: Use explicit memory barrier Minchan Kim
2013-03-31 23:45 ` Minchan Kim
2013-04-01 1:01 ` Kamezawa Hiroyuki [this message]
2013-04-01 1:01 ` Kamezawa Hiroyuki
2013-04-01 4:45 ` Minchan Kim
2013-04-01 4:45 ` Minchan Kim
2013-04-01 23:35 ` David Rientjes
2013-04-01 23:35 ` David Rientjes
2013-04-02 0:37 ` Minchan Kim
2013-04-02 0:37 ` Minchan Kim
2013-04-02 19:20 ` David Rientjes
2013-04-02 19:20 ` David Rientjes
2013-04-02 19:30 ` Hugh Dickins
2013-04-02 19:30 ` Hugh Dickins
2013-04-03 0:14 ` Minchan Kim
2013-04-03 0:14 ` Minchan Kim
2013-04-04 13:45 ` Andrea Arcangeli
2013-04-04 13:45 ` Andrea Arcangeli
2013-04-04 2:45 ` Simon Jeons
2013-04-04 2:45 ` Simon Jeons
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