From: Michal Hocko <mhocko@suse.cz>
To: zhong jiang <zhongjiang@huawei.com>
Cc: vbabka@suse.cz, qiuxishi@huawei.com, akpm@linux-foundation.org,
linux-mm@kvack.org, Mike Kravetz <mike.kravetz@oracle.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Mel Gorman <mgorman@suse.de>
Subject: Re: [PATCH v2] mm/hugetlb: fix race when migrate pages
Date: Wed, 20 Jul 2016 15:00:56 +0200 [thread overview]
Message-ID: <20160720130055.GL11249@dhcp22.suse.cz> (raw)
In-Reply-To: <20160720124501.GK11249@dhcp22.suse.cz>
On Wed 20-07-16 14:45:01, Michal Hocko wrote:
[...]
> I was talking to Mel (CCed) and he has raised a good question. So if you
> encounter a page under migration and fail to share the pmd with it how
> can you have a proper content of the target page in the end?
Hmm, I was staring into the code some more and it seems this would be OK
because we should hit hugetlb_no_page with the newel instantiated pmd
and associate it with a page from the radix tree. So unless I am missing
something the corruption shouldn't be possible.
I believe the post pmd_populate race is still there, though, so I
believe the approach should be rethought.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-07-20 13:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 13:45 zhongjiang
2016-07-20 7:38 ` Michal Hocko
2016-07-20 10:03 ` zhong jiang
2016-07-20 12:16 ` Michal Hocko
2016-07-20 12:45 ` Michal Hocko
2016-07-20 13:00 ` Michal Hocko [this message]
2016-07-20 13:24 ` Michal Hocko
2016-07-21 9:25 ` zhong jiang
-- strict thread matches above, loose matches on Subject: below --
2016-07-19 13:04 zhongjiang
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