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 09:48:18 -0800 [thread overview]
Message-ID: <20230119174818.up7haooxje4nzusu@offworld> (raw)
In-Reply-To: <20230119174101.rddtxk5xlamlnquh@techsingularity.net>
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
next prev parent reply other threads:[~2023-01-19 18:21 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 [this message]
2023-01-19 17:58 ` Davidlohr Bueso
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
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