From: Mel Gorman <mgorman@suse.de>
To: Michal Hocko <mhocko@suse.cz>
Cc: Linux-MM <linux-mm@kvack.org>, Hugh Dickins <hughd@google.com>,
David Gibson <david@gibson.dropbear.id.au>,
Ken Chen <kenchen@google.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -alternative] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables V2 (resend)
Date: Fri, 20 Jul 2012 15:51:21 +0100 [thread overview]
Message-ID: <20120720145121.GJ9222@suse.de> (raw)
In-Reply-To: <20120720143635.GE12434@tiehlicka.suse.cz>
On Fri, Jul 20, 2012 at 04:36:35PM +0200, Michal Hocko wrote:
> And here is my attempt for the fix (Hugh mentioned something similar
> earlier but he suggested using special flags in ptes or VMAs). I still
> owe doc. update and it hasn't been tested with too many configs and I
> could missed some definition updates.
> I also think that changelog could be much better, I will add (steal) the
> full bug description if people think that this way is worth going rather
> than the one suggested by Mel.
> To be honest I am not quite happy how I had to pollute generic mm code with
> something that is specific to a single architecture.
> Mel hammered it with the test case and it survived.
Tested-by: Mel Gorman <mgorman@suse.de>
This approach looks more or less like what I was expecting. I like that
the trick was applied to the page table page instead of using PTE tricks
or by bodging it with a VMA flag like I was thinking so kudos for that. I
also prefer this approach to trying to free the page tables on or near
huge_pmd_unshare()
In general I think this patch would execute better than mine because it is
far less heavy-handed but I share your concern that it changes the core MM
quite a bit for a corner case that only one architecture cares about. I am
completely biased of course, but I still prefer my patch because other than
an API change it keeps the bulk of the madness in arch/x86/mm/hugetlbpage.c
. I am also not concerned with the scalability of how quickly we can setup
page table sharing.
Hugh, I'm afraid you get to choose :)
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2012-07-20 14:51 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-20 13:49 [PATCH] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables v2 Mel Gorman
2012-07-20 14:11 ` [PATCH] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables V2 (resend) Mel Gorman
2012-07-20 14:29 ` Michal Hocko
2012-07-20 14:37 ` Mel Gorman
2012-07-20 14:40 ` Michal Hocko
2012-07-20 14:36 ` [PATCH -alternative] " Michal Hocko
2012-07-20 14:51 ` Mel Gorman [this message]
2012-07-23 4:04 ` Hugh Dickins
2012-07-23 11:40 ` Mel Gorman
2012-07-24 1:08 ` Hugh Dickins
2012-07-24 8:32 ` Michal Hocko
2012-07-24 9:34 ` Mel Gorman
2012-07-24 10:04 ` Michal Hocko
2012-07-24 19:23 ` Hugh Dickins
2012-07-25 8:36 ` Mel Gorman
2012-07-26 17:42 ` Rik van Riel
2012-07-26 18:04 ` Larry Woodman
2012-07-27 8:42 ` Mel Gorman
2012-07-26 18:37 ` Rik van Riel
2012-07-26 21:03 ` Larry Woodman
2012-07-27 3:48 ` Larry Woodman
2012-07-27 10:10 ` Larry Woodman
2012-07-27 10:23 ` Mel Gorman
2012-07-27 10:36 ` Larry Woodman
2012-07-30 19:11 ` Larry Woodman
2012-07-31 12:16 ` Hillf Danton
2012-07-31 12:46 ` Mel Gorman
2012-07-31 13:07 ` Larry Woodman
2012-07-31 13:29 ` Mel Gorman
2012-07-31 13:21 ` Michal Hocko
2012-07-31 17:49 ` Larry Woodman
2012-07-31 20:06 ` Michal Hocko
2012-07-31 20:57 ` Larry Woodman
2012-08-01 2:45 ` Larry Woodman
2012-08-01 8:20 ` Michal Hocko
2012-08-01 12:32 ` Michal Hocko
2012-08-01 15:06 ` Larry Woodman
2012-08-02 7:19 ` Michal Hocko
2012-08-02 7:37 ` Mel Gorman
2012-08-02 12:36 ` Michal Hocko
2012-08-02 13:33 ` Mel Gorman
2012-08-02 13:53 ` Michal Hocko
2012-07-31 18:03 ` Rik van Riel
2012-07-26 18:31 ` Rik van Riel
2012-07-27 9:02 ` Michal Hocko
2012-07-26 16:01 ` [PATCH] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables v2 Larry Woodman
2012-07-27 8:47 ` Mel Gorman
2012-07-26 21:00 ` Rik van Riel
2012-07-26 21:54 ` Hugh Dickins
2012-07-27 8:52 ` Mel Gorman
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