From: Michal Hocko <mhocko@kernel.org>
To: zhongjiang <zhongjiang@huawei.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill@shutemov.name>
Subject: Re: [PATCH] mm: fix account pmd page to the process
Date: Thu, 16 Jun 2016 17:43:24 +0200 [thread overview]
Message-ID: <20160616154324.GN6836@dhcp22.suse.cz> (raw)
In-Reply-To: <20160616154214.GA12284@dhcp22.suse.cz>
[It seems that this patch has been sent several times and this
particular copy didn't add Kirill who has added this code CC him now]
On Thu 16-06-16 17:42:14, Michal Hocko wrote:
> On Thu 16-06-16 19:36:11, zhongjiang wrote:
> > From: zhong jiang <zhongjiang@huawei.com>
> >
> > when a process acquire a pmd table shared by other process, we
> > increase the account to current process. otherwise, a race result
> > in other tasks have set the pud entry. so it no need to increase it.
> >
> > Signed-off-by: zhong jiang <zhongjiang@huawei.com>
> > ---
> > mm/hugetlb.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index 19d0d08..3b025c5 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -4189,10 +4189,9 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
> > if (pud_none(*pud)) {
> > pud_populate(mm, pud,
> > (pmd_t *)((unsigned long)spte & PAGE_MASK));
> > - } else {
> > + } else
> > put_page(virt_to_page(spte));
> > - mm_inc_nr_pmds(mm);
> > - }
>
> The code is quite puzzling but is this correct? Shouldn't we rather do
> mm_dec_nr_pmds(mm) in that path to undo the previous inc?
>
> > +
> > spin_unlock(ptl);
> > out:
> > pte = (pte_t *)pmd_alloc(mm, pud, addr);
> > --
> > 1.8.3.1
>
> --
> Michal Hocko
> SUSE Labs
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-06-16 15:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 11:36 [PATCH] mm: fix account pmd page to the process zhongjiang
2016-06-16 15:42 ` Michal Hocko
2016-06-16 15:43 ` Michal Hocko [this message]
2016-06-16 16:05 ` Mike Kravetz
2016-06-16 16:31 ` Michal Hocko
2016-06-16 16:47 ` Mike Kravetz
2016-06-17 12:25 ` Kirill A. Shutemov
2016-06-17 13:00 ` Michal Hocko
2016-06-17 14:25 ` Kirill A. Shutemov
2016-06-17 15:39 ` Mike Kravetz
2016-06-18 5:07 ` zhong jiang
2016-06-17 11:18 ` zhong jiang
[not found] <1466163941-12952-1-git-send-email-zhongjiang@huawei.com>
2016-06-17 12:01 ` zhong jiang
-- strict thread matches above, loose matches on Subject: below --
2016-06-17 11:56 zhongjiang
2016-06-17 12:21 ` Michal Hocko
2016-06-17 13:04 ` zhong jiang
[not found] <1466076175-23444-1-git-send-email-zhongjiang@huawei.com>
2016-06-16 11:30 ` zhong jiang
2016-06-16 11:28 zhongjiang
2016-06-16 11:17 zhongjiang
2016-06-16 11:16 zhongjiang
2016-06-16 11:13 zhongjiang
2016-06-16 7:47 zhongjiang
2016-06-15 14:48 zhongjiang
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