From: Matthew Wilcox <willy@infradead.org>
To: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Zhaoyang Huang <huangzhaoyang@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
ke.wang@unisoc.com, steve.kang@unisoc.com,
baocong.liu@unisoc.com, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC PATCH] mm: move xa forward when run across zombie page
Date: Fri, 14 Oct 2022 13:11:54 +0100 [thread overview]
Message-ID: <Y0lSChlclGPkwTeA@casper.infradead.org> (raw)
In-Reply-To: <1665725448-31439-1-git-send-email-zhaoyang.huang@unisoc.com>
On Fri, Oct 14, 2022 at 01:30:48PM +0800, zhaoyang.huang wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> Bellowing RCU stall is reported where kswapd traps in a live lock when shrink
> superblock's inode list. The direct reason is zombie page keeps staying on the
> xarray's slot and make the check and retry loop permanently. The root cause is unknown yet
> and supposed could be an xa update without synchronize_rcu etc. I would like to
> suggest skip this page to break the live lock as a workaround.
No, the underlying bug should be fixed.
> if (!folio || xa_is_value(folio))
> return folio;
>
> - if (!folio_try_get_rcu(folio))
> + if (!folio_try_get_rcu(folio)) {
> + xas_advance(xas, folio->index + folio_nr_pages(folio) - 1);
> goto reset;
> + }
You can't do this anyway. To call folio_nr_pages() and to look at
folio->index, you must have a refcount on the page, and this is the
path where we failed to get the refcount.
next prev parent reply other threads:[~2022-10-14 12:12 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-14 5:30 [RFC PATCH] mm: move xa forward when run across zombie page zhaoyang.huang
2022-10-14 12:11 ` Matthew Wilcox [this message]
2022-10-17 5:34 ` Zhaoyang Huang
2022-10-17 6:58 ` Zhaoyang Huang
2022-10-17 15:55 ` Matthew Wilcox
2022-10-18 2:52 ` Zhaoyang Huang
2022-10-18 3:09 ` Matthew Wilcox
2022-10-18 22:30 ` Dave Chinner
2022-10-19 1:16 ` Dave Chinner
2022-10-19 4:47 ` Dave Chinner
2022-10-19 5:48 ` Zhaoyang Huang
2022-10-19 13:06 ` Matthew Wilcox
2022-10-20 1:27 ` Zhaoyang Huang
2022-10-26 19:49 ` Matthew Wilcox
2022-10-27 1:57 ` Zhaoyang Huang
2022-10-19 11:49 ` Brian Foster
2022-10-20 2:04 ` Dave Chinner
2022-10-20 3:12 ` Zhaoyang Huang
2022-10-19 15:23 ` Matthew Wilcox
2022-10-19 22:04 ` Dave Chinner
2022-10-19 22:46 ` Dave Chinner
2022-10-19 23:42 ` Dave Chinner
2022-10-20 21:52 ` Matthew Wilcox
2022-10-26 8:38 ` Zhaoyang Huang
2022-10-26 14:38 ` Matthew Wilcox
2022-10-26 16:01 ` Matthew Wilcox
2022-10-28 4:05 ` Dave Chinner
2022-11-01 7:17 ` Dave Chinner
2024-04-11 7:04 ` Zhaoyang Huang
-- strict thread matches above, loose matches on Subject: below --
2022-10-21 21:37 Pulavarty, Badari
2022-10-21 22:31 ` Matthew Wilcox
2022-10-21 22:40 ` Pulavarty, Badari
2022-10-31 19:25 ` Pulavarty, Badari
2022-10-31 19:39 ` Hugh Dickins
2022-10-31 21:33 ` Pulavarty, Badari
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