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From: Oscar Salvador <osalvador@suse.de>
To: Rik van Riel <riel@surriel.com>
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
	linux-mm@kvack.org, Miaohe Lin <linmiaohe@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v2] mm: clean up hwpoison page cache page in fault path
Date: Tue, 15 Feb 2022 13:51:48 +0100	[thread overview]
Message-ID: <Yguh5JUGHln/iRJ8@localhost.localdomain> (raw)
In-Reply-To: <20220212213740.423efcea@imladris.surriel.com>

On Sat, Feb 12, 2022 at 09:37:40PM -0500, Rik van Riel wrote:
> Sometimes the page offlining code can leave behind a hwpoisoned clean
> page cache page. This can lead to programs being killed over and over
> and over again as they fault in the hwpoisoned page, get killed, and
> then get re-spawned by whatever wanted to run them.

Hi Rik,

Do you know how that exactly happens? We should not be really leaving
anything behind, and soft-offline (not hard) code works with the premise
of only poisoning a page in case it was contained, so I am wondering
what is going on here.

In-use pagecache pages are migrated away, and the actual page is
contained, and for clean ones, we already do the invalidate_inode_page()
and then contain it in case we succeed.

One scenario I can imagine this can happen is if by the time we call
page_handle_poison(), someone has taken another refcount on the page,
and the put_page() does not really free it, but I am not sure that
can happen.

-- 
Oscar Salvador
SUSE Labs


  parent reply	other threads:[~2022-02-15 12:51 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-13  2:37 [PATCH v2] mm: clean up hwpoison page cache page in fault path Rik van Riel
2022-02-14 23:24 ` Andrew Morton
2022-02-15  1:37   ` Rik van Riel
2022-02-15  5:15     ` HORIGUCHI NAOYA(堀口　直也)
2022-02-15 11:22 ` David Hildenbrand
2022-02-15 15:01   ` Rik van Riel
2022-02-15 15:06     ` David Hildenbrand
2022-02-15 12:51 ` Oscar Salvador [this message]
2022-02-15 15:04   ` Rik van Riel
2022-02-16  2:13   ` Miaohe Lin
2022-02-21 12:54     ` Oscar Salvador
2022-02-21 13:19       ` Miaohe Lin
2022-02-21 12:55 ` Oscar Salvador

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