From: Andi Kleen <andi@firstfloor.org>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>, Wu Fengguang <fengguang.wu@intel.com>,
Jun'ichi Nomura <j-nomura@ce.jp.nec.com>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/7] hugetlb: hugepage migration core
Date: Tue, 6 Jul 2010 09:13:37 +0200 [thread overview]
Message-ID: <20100706071337.GA20403@basil.fritz.box> (raw)
In-Reply-To: <20100706033342.GA10626@spritzera.linux.bs1.fc.nec.co.jp>
On Tue, Jul 06, 2010 at 12:33:42PM +0900, Naoya Horiguchi wrote:
> > There's more code that handles LRU in this file. Do they all handle huge pages
> > correctly?
> >
> > I also noticed we do not always lock all sub pages in the huge page. Now if
> > IO happens it will lock on subpages, not the head page. But this code
> > handles all subpages as a unit. Could this cause locking problems?
> > Perhaps it would be safer to lock all sub pages always? Or would
> > need to audit other page users to make sure they always lock on the head
> > and do the same here.
> >
> > Hmm page reference counts may have the same issue?
>
> If we try to implement paging out of hugepage in the future, we need to
> solve all these problems straightforwardly. But at least for now we can
> skirt them by not touching LRU code for hugepage extension.
We need the page lock to avoid migrating pages that are currently
under IO. This can happen even without swapping when the process
manually starts IO.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
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next prev parent reply other threads:[~2010-07-06 7:13 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-02 5:47 [PATCH 0/7] hugepage migration Naoya Horiguchi
2010-07-02 5:47 ` [PATCH 1/7] hugetlb: add missing unlock in avoidcopy path in hugetlb_cow() Naoya Horiguchi
2010-07-02 8:31 ` Andi Kleen
2010-07-05 8:44 ` Naoya Horiguchi
2010-07-07 22:17 ` Andi Kleen
2010-07-02 5:47 ` [PATCH 2/7] hugetlb, HWPOISON: move PG_HWPoison bit check Naoya Horiguchi
2010-07-02 5:47 ` [PATCH 3/7] hugetlb: add allocate function for hugepage migration Naoya Horiguchi
2010-07-02 9:08 ` Andi Kleen
2010-07-05 8:46 ` Naoya Horiguchi
2010-07-05 9:28 ` Andi Kleen
2010-07-02 5:47 ` [PATCH 4/7] hugetlb: add hugepage check in mem_cgroup_{register,end}_migration() Naoya Horiguchi
2010-07-02 9:11 ` Andi Kleen
2010-07-02 5:47 ` [PATCH 5/7] hugetlb: pin oldpage in page migration Naoya Horiguchi
2010-07-05 9:45 ` Andi Kleen
2010-07-06 15:54 ` Christoph Lameter
2010-07-07 6:40 ` Naoya Horiguchi
2010-07-02 5:47 ` [PATCH 6/7] hugetlb: hugepage migration core Naoya Horiguchi
2010-07-05 9:59 ` Andi Kleen
2010-07-06 3:33 ` Naoya Horiguchi
2010-07-06 7:13 ` Andi Kleen [this message]
2010-07-07 6:05 ` Naoya Horiguchi
2010-07-07 9:27 ` Andi Kleen
2010-07-08 5:44 ` Naoya Horiguchi
2010-07-08 6:49 ` Andi Kleen
2010-07-06 16:02 ` Christoph Lameter
2010-07-07 6:44 ` Naoya Horiguchi
2010-07-06 16:00 ` Christoph Lameter
2010-07-07 6:45 ` Naoya Horiguchi
2010-07-02 5:47 ` [PATCH 7/7] hugetlb, HWPOISON: soft offlining for hugepage Naoya Horiguchi
2010-07-05 10:28 ` Andi Kleen
2010-07-02 8:30 ` [PATCH 0/7] hugepage migration Andi Kleen
2010-07-05 8:44 ` Naoya Horiguchi
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