From: Mel Gorman <mel@csn.ul.ie>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux-foundation.org>,
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 04/10] hugetlb: hugepage migration core
Date: Wed, 22 Sep 2010 09:40:35 +0100 [thread overview]
Message-ID: <20100922084035.GC1382@csn.ul.ie> (raw)
In-Reply-To: <20100922045907.GC2538@spritzera.linux.bs1.fc.nec.co.jp>
On Wed, Sep 22, 2010 at 01:59:07PM +0900, Naoya Horiguchi wrote:
> On Mon, Sep 20, 2010 at 12:10:55PM +0100, Mel Gorman wrote:
> > On Wed, Sep 08, 2010 at 10:19:35AM +0900, Naoya Horiguchi wrote:
> ...
> > > @@ -95,26 +96,34 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
> > > pte_t *ptep, pte;
> > > spinlock_t *ptl;
> > >
> > > - pgd = pgd_offset(mm, addr);
> > > - if (!pgd_present(*pgd))
> > > - goto out;
> > > + if (unlikely(PageHuge(new))) {
> > > + ptep = huge_pte_offset(mm, addr);
> > > + if (!ptep)
> > > + goto out;
> > > + ptl = &mm->page_table_lock;
> > > + } else {
> > > + pgd = pgd_offset(mm, addr);
> > > + if (!pgd_present(*pgd))
> > > + goto out;
> > >
> > > - pud = pud_offset(pgd, addr);
> > > - if (!pud_present(*pud))
> > > - goto out;
> > > + pud = pud_offset(pgd, addr);
> > > + if (!pud_present(*pud))
> > > + goto out;
> > >
> >
> > Why are the changes to teh rest of the walkers necessary? Instead, why
> > did you not identify which PTL lock you needed and then goto the point
> > where spin_lock(ptl) is called? Similar to what page_check_address()
> > does for example.
>
> This is because Andi-san commented to avoid using goto sentense.
> But honestly I'm not sure which is a clear way.
>
Ok, personally I would prefer to have matched page_check_address() so we use
similar code patterns when the intention is the same but as functionally it
seems fine, I'm not going to fight over it either.
Thanks.
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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next prev parent reply other threads:[~2010-09-22 8:40 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-08 1:19 [PATCH 0/10] Hugepage migration (v5) Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 01/10] hugetlb: fix metadata corruption in hugetlb_fault() Naoya Horiguchi
2010-09-20 10:47 ` Mel Gorman
2010-09-22 20:41 ` Christoph Lameter
2010-09-08 1:19 ` [PATCH 02/10] hugetlb: add allocate function for hugepage migration Naoya Horiguchi
2010-09-20 10:59 ` Mel Gorman
2010-09-22 4:41 ` Naoya Horiguchi
2010-09-22 8:37 ` Mel Gorman
2010-09-22 21:05 ` Christoph Lameter
2010-09-23 8:49 ` Mel Gorman
2010-09-23 16:02 ` Christoph Lameter
2010-09-08 1:19 ` [PATCH 03/10] hugetlb: redefine hugepage copy functions Naoya Horiguchi
2010-09-20 11:03 ` Mel Gorman
2010-09-20 11:15 ` Andi Kleen
2010-09-20 11:18 ` Mel Gorman
2010-09-23 16:21 ` Christoph Lameter
2010-09-24 3:24 ` Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 04/10] hugetlb: hugepage migration core Naoya Horiguchi
2010-09-20 11:10 ` Mel Gorman
2010-09-22 4:59 ` Naoya Horiguchi
2010-09-22 8:40 ` Mel Gorman [this message]
2010-09-23 16:52 ` Christoph Lameter
2010-09-24 5:58 ` Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 05/10] HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page() Naoya Horiguchi
2010-09-23 16:54 ` Christoph Lameter
2010-09-08 1:19 ` [PATCH 06/10] hugetlb: move refcounting in hugepage allocation inside hugetlb_lock Naoya Horiguchi
2010-09-23 17:12 ` Christoph Lameter
2010-09-24 6:47 ` Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 07/10] HWPOSION, hugetlb: recover from free hugepage error when !MF_COUNT_INCREASED Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 08/10] HWPOISON, hugetlb: soft offlining for hugepage Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 09/10] HWPOISON, hugetlb: fix unpoison " Naoya Horiguchi
2010-09-08 1:19 ` [PATCH 10/10] page-types.c: fix name of unpoison interface Naoya Horiguchi
2010-09-09 10:33 ` [PATCH 0/10] Hugepage migration (v5) Andi Kleen
2010-09-09 22:56 ` Naoya Horiguchi
2010-09-20 11:14 ` Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2010-09-03 4:37 [PATCH 0/10] Hugepage migration (v4) Naoya Horiguchi
2010-09-03 4:37 ` [PATCH 04/10] hugetlb: hugepage migration core Naoya Horiguchi
2010-09-03 14:10 ` Christoph Lameter
2010-09-07 1:25 ` Naoya Horiguchi
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