From: Linus Torvalds <torvalds@linux-foundation.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan.kim@gmail.com>,
Christoph Lameter <cl@linux.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack
Date: Sun, 9 May 2010 18:49:32 -0700 (PDT) [thread overview]
Message-ID: <alpine.LFD.2.00.1005091847260.3711@i5.linux-foundation.org> (raw)
In-Reply-To: <20100510104039.98332e67.kamezawa.hiroyu@jp.fujitsu.com>
On Mon, 10 May 2010, KAMEZAWA Hiroyuki wrote:
>
> Hmm. vm_flags is still 32bit..(I think it should be long long)
>
> Using combination of existing flags...
>
> #define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEC_READ)
>
> Can be used instead of checking mapcount, I think.
Ahh, yes. We can also do things like not having VM_MAY_READ/WRITE set.
That's impossible on a real mapping - even if it's not readable, it is
always something you could mprotect to _be_ readable.
The point being, we can make the tests more explicit, and less "magic that
happens to work". As long as it's ok to just say "don't migrate pages in
this mapping yet, because we're still setting it up".
Linus
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next prev parent reply other threads:[~2010-05-10 1:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 23:20 [PATCH 0/2] Fix migration races in rmap_walk() V7 Mel Gorman
2010-05-06 23:20 ` [PATCH 1/2] mm,migration: Prevent rmap_walk_[anon|ksm] seeing the wrong VMA information Mel Gorman
2010-05-07 0:56 ` KAMEZAWA Hiroyuki
2010-05-07 16:26 ` Mel Gorman
2010-05-08 15:39 ` Andrea Arcangeli
2010-05-08 17:02 ` Linus Torvalds
2010-05-08 18:04 ` Andrea Arcangeli
2010-05-08 19:51 ` Linus Torvalds
2010-05-09 19:23 ` Mel Gorman
2010-05-06 23:20 ` [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack Mel Gorman
2010-05-07 1:40 ` Linus Torvalds
2010-05-07 1:57 ` KAMEZAWA Hiroyuki
2010-05-07 2:12 ` Linus Torvalds
2010-05-07 4:19 ` KAMEZAWA Hiroyuki
2010-05-07 14:18 ` Linus Torvalds
2010-05-09 19:21 ` Mel Gorman
2010-05-09 19:56 ` Linus Torvalds
2010-05-09 20:06 ` Linus Torvalds
2010-05-09 20:20 ` Linus Torvalds
2010-05-10 0:40 ` KAMEZAWA Hiroyuki
2010-05-10 1:30 ` Linus Torvalds
2010-05-10 1:32 ` Linus Torvalds
2010-05-10 1:40 ` KAMEZAWA Hiroyuki
2010-05-10 1:49 ` Linus Torvalds [this message]
2010-05-10 13:24 ` Mel Gorman
2010-05-10 23:55 ` KAMEZAWA Hiroyuki
2010-05-10 0:42 ` KAMEZAWA Hiroyuki
2010-05-10 14:02 ` Mel Gorman
2010-05-10 13:49 ` Mel Gorman
2010-05-10 0:32 ` KAMEZAWA Hiroyuki
2010-05-07 9:16 ` Mel Gorman
2010-05-07 8:13 ` [PATCH 0/2] Fix migration races in rmap_walk() V7 KAMEZAWA Hiroyuki
-- strict thread matches above, loose matches on Subject: below --
2010-05-06 15:33 [PATCH 0/2] Fix migration races in rmap_walk() V6 Mel Gorman
2010-05-06 15:33 ` [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack Mel Gorman
2010-05-05 13:14 [PATCH 0/2] Fix migration races in rmap_walk() V5 Mel Gorman
2010-05-05 13:14 ` [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack Mel Gorman
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