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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Yang Shi <shy828301@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Michal Hocko <mhocko@suse.com>, Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH] mm: avoid blocking lock_page() in kcompactd
Date: Thu, 9 Jan 2020 20:51:51 -0800	[thread overview]
Message-ID: <CAM_iQpWr2HLkW=ZSjZmiOpJyUG7T1QaWQOSW7vi34hqd2L4Bmg@mail.gmail.com> (raw)
In-Reply-To: <CAM_iQpWvrR9cVA31tD7Mvx0yTN=NDXQ-NMYStH9UB3Rb6WzmeA@mail.gmail.com>

On Thu, Jan 9, 2020 at 5:01 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
> I tried to dump the process stacks after we saw the hung task
> with /proc/X/stack (apparently sysrq is not an option for production),
> but I didn't find anything useful. I didn't see any other process
> hung in lock_page() either, all mm-related kernel threads were sleeping
> (non-D) at the time I debugged. So, it is possible there was some place
> missing a unlock_page() too, which is too late to debug after the hung
> task was reported.

Never mind. I found the process locking the page, /proc/X/stack apparently
fools me by hiding page fault stack. :-/


  reply	other threads:[~2020-01-10  4:52 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-09 22:56 [PATCH] mm: avoid blocking lock_page() in kcompactd Cong Wang
2020-01-10  0:28 ` Yang Shi
2020-01-10  1:01   ` Cong Wang
2020-01-10  4:51     ` Cong Wang [this message]
2020-01-10  7:38 ` Michal Hocko
2020-01-20 22:48   ` Cong Wang
2020-01-21  9:00     ` Michal Hocko
2020-01-26 19:53       ` Cong Wang
2020-01-26 23:39         ` Matthew Wilcox
2020-01-27 15:00           ` Michal Hocko
2020-01-27 19:06             ` Matthew Wilcox
2020-01-28  1:25               ` Yang Shi
2020-01-28  6:03                 ` Matthew Wilcox
2020-01-28  8:17               ` Michal Hocko
2020-01-28  8:30                 ` Matthew Wilcox
2020-01-28  9:13                   ` Michal Hocko
2020-01-28 10:48                     ` Matthew Wilcox
2020-01-28 11:39                       ` Michal Hocko
2020-01-28 19:44                         ` Cong Wang
2020-01-30 22:52                           ` Cong Wang
2020-02-13  7:48                         ` Michal Hocko
2020-02-13 16:46                           ` Matthew Wilcox
2020-02-13 17:08                             ` Michal Hocko
2020-02-14  4:27                               ` Matthew Wilcox
2020-02-14  6:55                                 ` Michal Hocko
2020-01-27 14:49         ` Michal Hocko
2020-01-28  0:46           ` Cong Wang
2020-01-28  8:22             ` Michal Hocko
2020-01-10  9:22 ` Mel Gorman
2020-01-20 22:41   ` Cong Wang
2020-01-21 19:21     ` Yang Shi
2020-01-21  8:26   ` Hillf Danton
2020-01-21  9:06     ` Michal Hocko

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