From: Hugh Dickins <hughd@google.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Hillf Danton <dhillf@gmail.com>, Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Linux-MM <linux-mm@kvack.org>,
Rik van Riel <riel@redhat.com>
Subject: Re: oops in copy_page_rep()
Date: Tue, 8 Jan 2013 20:23:46 -0800 (PST) [thread overview]
Message-ID: <alpine.LNX.2.00.1301082020280.2351@eggly.anvils> (raw)
In-Reply-To: <20130108173747.GF9163@redhat.com>
On Tue, 8 Jan 2013, Andrea Arcangeli wrote:
>
> Looking at this, one thing that isn't clear is where the page_count is
> checked in migrate_misplaced_transhuge_page. Ok that it's unable to
> migrate anon transhuge COW shared pages so it doesn't need to mess
> with rmap (the mapcount check makes it safe), but it shouldn't be
> allowed to migrate memory that has gup direct-IO in flight (and that
> can only be detected with a page_count vs mapcount check). Real
> migrate does page_freeze_refs to be safe. Mel comments?
Yes, I protested to Mel about that before the holidays, and he
quickly provided a patch, now in akpm's tree; but checking it again
today, I believe it's still not quite right yet - see other mail.
Hugh
next prev parent reply other threads:[~2013-01-09 4:24 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-05 15:22 Dave Jones
2013-01-06 3:57 ` Linus Torvalds
2013-01-07 0:37 ` Dave Jones
2013-01-07 3:38 ` Hugh Dickins
2013-01-06 11:55 ` Hillf Danton
2013-01-06 16:10 ` Dave Jones
2013-01-06 19:06 ` Hugh Dickins
2013-01-07 12:24 ` Hillf Danton
2013-01-07 17:34 ` Linus Torvalds
2013-01-08 13:04 ` Hillf Danton
2013-01-08 15:37 ` Linus Torvalds
2013-01-08 16:31 ` Kirill A. Shutemov
2013-01-08 16:52 ` Linus Torvalds
2013-01-08 17:30 ` Kirill A. Shutemov
2013-01-08 17:38 ` Linus Torvalds
2013-01-08 17:49 ` Andrea Arcangeli
2013-01-08 18:03 ` Kirill A. Shutemov
2013-01-11 7:50 ` Simon Jeons
2013-01-11 14:01 ` Andrea Arcangeli
2013-01-08 17:37 ` Andrea Arcangeli
2013-01-08 17:51 ` Linus Torvalds
2013-01-08 18:03 ` Andrea Arcangeli
2013-01-08 18:21 ` Linus Torvalds
2013-01-09 11:38 ` Hillf Danton
2013-01-09 4:23 ` Hugh Dickins [this message]
2013-01-09 11:44 ` Mel Gorman
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