From: Davidlohr Bueso <dave@stgolabs.net>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Linux-RT <linux-rt-users@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] locking/rwbase: Prevent indefinite writer starvation
Date: Thu, 19 Jan 2023 09:58:18 -0800 [thread overview]
Message-ID: <20230119175818.2rc4uvxkr3o6u37o@offworld> (raw)
In-Reply-To: <20230119174818.up7haooxje4nzusu@offworld>
On Thu, 19 Jan 2023, Davidlohr Bueso wrote:
>On Thu, 19 Jan 2023, Mel Gorman wrote:
>
>>The race could be closed by moving wait_lock acquisition before the
>>atomic_sub in rwbase_write_lock() but it expands the scope of the wait_lock
>>and I'm not sure that's necessary for either correctness or preventing
>>writer starvation. It's a more straight-forward fix but expanding the
>>scope of a lock unnecessarily has been unpopular in the past.
>
>Curiously, this is the documented behavior:
>
> * down_write/write_lock()
> * 1) Lock rtmutex
> * 2) Remove the reader BIAS to force readers into the slow path
Nevermind, this was the rtmutex, not the wait_lock, sorry for the noise.
next prev parent reply other threads:[~2023-01-19 18:24 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-17 8:38 [PATCH v2] locking/rwbase: Prevent indefinite writer starvation Mel Gorman
[not found] ` <20230117105031.2512-1-hdanton@sina.com>
2023-01-17 12:18 ` Mel Gorman
2023-01-17 14:22 ` Sebastian Andrzej Siewior
2023-01-17 16:50 ` Mel Gorman
2023-01-18 10:45 ` Ingo Molnar
2023-01-18 16:00 ` Mel Gorman
2023-01-18 15:25 ` Sebastian Andrzej Siewior
2023-01-18 17:31 ` Mel Gorman
2023-01-19 8:25 ` Sebastian Andrzej Siewior
2023-01-19 11:02 ` Mel Gorman
2023-01-19 16:28 ` Sebastian Andrzej Siewior
2023-01-19 17:41 ` Mel Gorman
2023-01-19 17:48 ` Davidlohr Bueso
2023-01-19 17:58 ` Davidlohr Bueso [this message]
2023-01-20 8:25 ` Sebastian Andrzej Siewior
2023-01-20 13:24 ` Mel Gorman
2023-01-20 13:38 ` Sebastian Andrzej Siewior
2023-01-20 14:07 ` Mel Gorman
2023-01-20 15:36 ` Davidlohr Bueso
[not found] ` <20230119011538.3247-1-hdanton@sina.com>
2023-01-19 8:32 ` Sebastian Andrzej Siewior
[not found] ` <20230119135903.3524-1-hdanton@sina.com>
2023-01-19 16:36 ` Sebastian Andrzej Siewior
[not found] ` <20230120093711.3862-1-hdanton@sina.com>
2023-01-20 18:34 ` Sebastian Andrzej Siewior
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230119175818.2rc4uvxkr3o6u37o@offworld \
--to=dave@stgolabs.net \
--cc=bigeasy@linutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).