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From: Michal Hocko <mhocko@suse.com>
To: Muchun Song <songmuchun@bytedance.com>
Cc: mike.kravetz@oracle.com, akpm@linux-foundation.org,
	n-horiguchi@ah.jp.nec.com, ak@linux.intel.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH v3 3/6] mm: hugetlb: fix a race between freeing and dissolving the page
Date: Tue, 12 Jan 2021 11:02:13 +0100	[thread overview]
Message-ID: <20210112100213.GK22493@dhcp22.suse.cz> (raw)
In-Reply-To: <20210110124017.86750-4-songmuchun@bytedance.com>

On Sun 10-01-21 20:40:14, Muchun Song wrote:
[...]
> @@ -1770,6 +1788,14 @@ int dissolve_free_huge_page(struct page *page)
>  		int nid = page_to_nid(head);
>  		if (h->free_huge_pages - h->resv_huge_pages == 0)
>  			goto out;
> +
> +		/*
> +		 * We should make sure that the page is already on the free list
> +		 * when it is dissolved.
> +		 */
> +		if (unlikely(!PageHugeFreed(head)))
> +			goto out;
> +

Do you really want to report EBUSY in this case? This doesn't make much
sense to me TBH. I believe you want to return 0 same as when you race
and the page is no longer PageHuge.

>  		/*
>  		 * Move PageHWPoison flag from head page to the raw error page,
>  		 * which makes any subpages rather than the error page reusable.
> -- 
> 2.11.0

-- 
Michal Hocko
SUSE Labs


  parent reply	other threads:[~2021-01-12 10:02 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-10 12:40 [PATCH v3 0/6] Fix some bugs about HugeTLB code Muchun Song
2021-01-10 12:40 ` [PATCH v3 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Muchun Song
2021-01-12  9:42   ` Michal Hocko
2021-01-12  9:43     ` [External] " Muchun Song
2021-01-12 11:00   ` David Hildenbrand
2021-01-12 11:11     ` David Hildenbrand
2021-01-12 11:27       ` Michal Hocko
2021-01-12 11:34         ` David Hildenbrand
2021-01-12 12:16           ` Michal Hocko
2021-01-12 14:23             ` Michal Hocko
2021-01-12 14:41               ` David Hildenbrand
2021-01-12 14:53                 ` Michal Hocko
2021-01-12 20:12                   ` Mike Kravetz
2021-01-12 13:40       ` [External] " Muchun Song
2021-01-12 13:51         ` David Hildenbrand
2021-01-12 14:17           ` Muchun Song
2021-01-12 14:28             ` David Hildenbrand
2021-01-12 14:59               ` Muchun Song
2021-01-10 12:40 ` [PATCH v3 2/6] mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page Muchun Song
2021-01-11 23:04   ` Mike Kravetz
2021-01-12  9:45   ` Michal Hocko
2021-01-10 12:40 ` [PATCH v3 3/6] mm: hugetlb: fix a race between freeing and dissolving the page Muchun Song
2021-01-12  1:06   ` Mike Kravetz
2021-01-12 10:02   ` Michal Hocko [this message]
2021-01-12 10:13     ` [External] " Muchun Song
2021-01-12 11:17       ` Michal Hocko
2021-01-12 11:43         ` Muchun Song
2021-01-12 12:37           ` Michal Hocko
2021-01-12 15:05             ` Muchun Song
2021-01-10 12:40 ` [PATCH v3 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page Muchun Song
2021-01-12  1:20   ` Mike Kravetz
2021-01-12  8:33     ` Michal Hocko
2021-01-12  9:51       ` [External] " Muchun Song
2021-01-12 10:06         ` Michal Hocko
2021-01-12 10:49           ` Muchun Song
2021-01-12 11:11             ` Michal Hocko
2021-01-12 11:34               ` Muchun Song
2021-01-10 12:40 ` [PATCH v3 5/6] mm: hugetlb: fix a race between isolating and freeing page Muchun Song
2021-01-10 12:40 ` [PATCH v3 6/6] mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active Muchun Song

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