From: Linus Torvalds <torvalds@linux-foundation.org>
To: Matthieu Baerts <matthieu.baerts@tessares.net>
Cc: Michael Larabel <Michael@michaellarabel.com>,
Matthew Wilcox <willy@infradead.org>,
Amir Goldstein <amir73il@gmail.com>,
"Ted Ts'o" <tytso@google.com>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
Jan Kara <jack@suse.cz>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: Kernel Benchmarking
Date: Tue, 15 Sep 2020 11:47:45 -0700 [thread overview]
Message-ID: <CAHk-=wimjnAsoDUjkanC2BQTntwK4qtzmPdBbtmgM=MMhR6B2w@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=wimdSWe+GVBKwB0_=ZKX2ZN5JEqK5yA99toab4MAoYAsg@mail.gmail.com>
On Tue, Sep 15, 2020 at 11:27 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Every one of them is in the "io_schedule()" in the filemap_fault()
> path, although two of them seem to be in file_fdatawait_range() rather
> than in the lock_page() code itself (so they are also waiting on a
> page bit, but they are waiting for the writeback bit to clear).
No, that seems to be just stale entries on the stack from a previous
system call, rather than a real trace. There's no way to reach
file_fdatawait_range() from mlockall() that I can see.
So I'm not entirely sure why the stack trace for two of the processes
looks a bit different, but they all look like they should be in
__lock_page_killable().
It's possible those two were woken up (by another CPU) and their stack
is in flux. They also have "wake_up_page_bit()" as a stale entry on
their stack, so that's not entirely unlikely.
So that sysrq-W state shows that yes, people are stuck waiting for a
page, but that wasn't exactly unexpected.
Linus
next prev parent reply other threads:[~2020-09-15 18:48 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAHk-=wiZnE409WkTOG6fbF_eV1LgrHBvMtyKkpTqM9zT5hpf9A@mail.gmail.com>
[not found] ` <4ced9401-de3d-b7c9-9976-2739e837fafc@MichaelLarabel.com>
[not found] ` <CAHk-=wj+Qj=wXByMrAx3T8jmw=soUetioRrbz6dQaECx+zjMtg@mail.gmail.com>
[not found] ` <CAHk-=wgOPjbJsj-LeLc-JMx9Sz9DjGF66Q+jQFJROt9X9utdBg@mail.gmail.com>
[not found] ` <CAHk-=wjjK7PTnDZNi039yBxSHtAqusFoRrZzgMNTiYkJYdNopw@mail.gmail.com>
[not found] ` <aa90f272-1186-f9e1-8fdb-eefd332fdae8@MichaelLarabel.com>
[not found] ` <CAHk-=wh_31_XBNHbdF7EUJceLpEpwRxVF+_1TONzyBUym6Pw4w@mail.gmail.com>
[not found] ` <e24ef34d-7b1d-dd99-082d-28ca285a79ff@MichaelLarabel.com>
[not found] ` <CAHk-=wgEE4GuNjcRaaAvaS97tW+239-+tjcPjTq2FGhEuM8HYg@mail.gmail.com>
[not found] ` <6e1d8740-2594-c58b-ff02-a04df453d53c@MichaelLarabel.com>
[not found] ` <CAHk-=wgJ3-cEkU-5zXFPvRCHKkCCuKxVauYWGphjePEhJJgtgQ@mail.gmail.com>
[not found] ` <d2023f4c-ef14-b877-b5bb-e4f8af332abc@MichaelLarabel.com>
[not found] ` <CAHk-=wiz=J=8mJ=zRG93nuJ9GtQAm5bSRAbWJbWZuN4Br38+EQ@mail.gmail.com>
2020-09-11 0:05 ` Kernel Benchmarking Linus Torvalds
2020-09-11 0:49 ` Michael Larabel
2020-09-11 2:20 ` Linus Torvalds
[not found] ` <0cbc959e-1b8d-8d7e-1dc6-672cf5b3899a@MichaelLarabel.com>
2020-09-11 16:19 ` Linus Torvalds
2020-09-11 22:07 ` Linus Torvalds
2020-09-11 22:37 ` Michael Larabel
2020-09-12 7:28 ` Amir Goldstein
2020-09-12 10:32 ` Michael Larabel
2020-09-12 14:37 ` Matthew Wilcox
2020-09-12 14:44 ` Michael Larabel
2020-09-15 3:32 ` Matthew Wilcox
2020-09-15 10:39 ` Jan Kara
2020-09-15 13:52 ` Matthew Wilcox
[not found] ` <658ae026-32d9-0a25-5a59-9c510d6898d5@MichaelLarabel.com>
2020-09-14 17:47 ` Linus Torvalds
2020-09-14 20:21 ` Matthieu Baerts
2020-09-14 20:53 ` Linus Torvalds
2020-09-15 0:42 ` Linus Torvalds
2020-09-15 15:34 ` Matthieu Baerts
2020-09-15 18:27 ` Linus Torvalds
2020-09-15 18:47 ` Linus Torvalds [this message]
2020-09-15 19:26 ` Matthieu Baerts
2020-09-15 19:32 ` Linus Torvalds
2020-09-15 19:56 ` Matthieu Baerts
2020-09-15 23:35 ` Linus Torvalds
2020-09-16 10:34 ` Jan Kara
2020-09-16 18:47 ` Linus Torvalds
[not found] ` <9a92bf16-02c5-ba38-33c7-f350588ac874@tessares.net>
2020-09-15 19:24 ` Linus Torvalds
2020-09-15 19:38 ` Matthieu Baerts
2020-09-15 18:31 ` Linus Torvalds
2020-09-15 14:21 ` Michael Larabel
2020-09-15 17:52 ` Linus Torvalds
2020-09-17 17:51 ` Linus Torvalds
2020-09-17 18:23 ` Matthew Wilcox
2020-09-17 18:30 ` Linus Torvalds
2020-09-17 18:50 ` Matthew Wilcox
2020-09-17 19:00 ` Linus Torvalds
2020-09-17 19:27 ` Matthew Wilcox
2020-09-17 19:47 ` Linus Torvalds
2020-09-18 0:39 ` Sedat Dilek
2020-09-18 0:40 ` Sedat Dilek
2020-09-18 20:25 ` Sedat Dilek
2020-09-20 17:06 ` Linus Torvalds
2020-09-20 17:14 ` Sedat Dilek
2020-09-20 17:40 ` Linus Torvalds
2020-09-20 18:00 ` Sedat Dilek
2020-09-20 23:23 ` Dave Chinner
2020-09-20 23:31 ` Linus Torvalds
2020-09-20 23:40 ` Linus Torvalds
2020-09-21 1:20 ` Dave Chinner
2020-09-12 15:53 ` Matthew Wilcox
2020-09-12 17:59 ` Linus Torvalds
2020-09-12 20:32 ` Rogério Brito
2020-09-14 9:33 ` Jan Kara
2020-09-12 20:58 ` Josh Triplett
2020-09-12 20:59 ` James Bottomley
2020-09-12 21:15 ` Linus Torvalds
2020-09-12 22:32 ` Matthew Wilcox
2020-09-13 0:40 ` Dave Chinner
2020-09-13 2:39 ` Linus Torvalds
2020-09-13 3:40 ` Matthew Wilcox
2020-09-13 23:45 ` Dave Chinner
2020-09-14 3:31 ` Matthew Wilcox
2020-09-15 14:28 ` Chris Mason
2020-09-15 9:27 ` Jan Kara
2020-09-13 3:18 ` Matthew Wilcox
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