From: Matthew Wilcox <willy@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>,
Amir Goldstein <amir73il@gmail.com>,
Hugh Dickins <hughd@google.com>,
Michael Larabel <Michael@michaellarabel.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: Sun, 13 Sep 2020 04:40:04 +0100 [thread overview]
Message-ID: <20200913034004.GF6583@casper.infradead.org> (raw)
In-Reply-To: <CAHk-=wh5Lyr9Tr8wpNDXKeNt=Ngc3jwWaOsN_WbQr+1dAuhJSQ@mail.gmail.com>
On Sat, Sep 12, 2020 at 07:39:31PM -0700, Linus Torvalds wrote:
> The real worry with (d) is that we are using the page lock for other
> things too, not *just* the truncate check. Things where the inode lock
> wouldn't be helping, like locking against throwing pages out of the
> page cache entirely, or the hugepage splitting/merging etc. It's not
> being truncated, it's just the VM shrinking the cache or modifying
> things in other ways.
Actually, hugepage splitting is done under the protection of page freezing
where we temporarily set the refcount to zero, so pagecache lookups spin
rather than sleep on the lock. Quite nasty, but also quite rare.
> But the page locking code does have some extreme downsides, exactly
> because there are so _many_ pages and we end up having to play some
The good news is that the THP patchset is making good progress. I have
seven consecutive successful three-hour runs of xfstests, so maybe we'll
see fewer pages in the future.
next prev parent reply other threads:[~2020-09-13 3:40 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAHk-=wiZnE409WkTOG6fbF_eV1LgrHBvMtyKkpTqM9zT5hpf9A@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>
[not found] ` <CAHk-=wimM2kckaYj7spUJwehZkSYxK9RQqu3G392BE=73dyKtg@mail.gmail.com>
[not found] ` <8bb582d2-2841-94eb-8862-91d1225d5ebc@MichaelLarabel.com>
[not found] ` <CAHk-=wjqE_a6bpZyDQ4DCrvj_Dv2RwQoY7wN91kj8y-tZFRvEA@mail.gmail.com>
[not found] ` <0cbc959e-1b8d-8d7e-1dc6-672cf5b3899a@MichaelLarabel.com>
[not found] ` <CAHk-=whP-7Uw9WgWgjRgF1mCg+NnkOPpWjVw+a9M3F9C52DrVg@mail.gmail.com>
[not found] ` <CAHk-=wjfw3U5eTGWLaisPHg1+jXsCX=xLZgqPx4KJeHhEqRnEQ@mail.gmail.com>
[not found] ` <a2369108-7103-278c-9f10-6309a0a9dc3b@MichaelLarabel.com>
2020-09-12 7:28 ` Kernel Benchmarking 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
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 [this message]
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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