From: Peter Zijlstra <peterz@infradead.org>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: Waiman Long <longman@redhat.com>, Ingo Molnar <mingo@redhat.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] locking/rwsem: Make owner store task pointer of last owning reader
Date: Tue, 11 Sep 2018 21:38:24 +0200 [thread overview]
Message-ID: <20180911193824.GW24106@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180911192122.GD3902@linux-r8p5>
On Tue, Sep 11, 2018 at 12:21:22PM -0700, Davidlohr Bueso wrote:
> On Mon, 10 Sep 2018, Peter Zijlstra wrote:
>
> > [ RT has something along those lines, and I have half a patch that
> > starts doing that too, but I never found enough time to really work on
> > it :-( ]
>
> But don't rt rwsems act pretty much like a regular mutex in that it only
> allows readers to nest, not share the lock because of priority inversion
> scenarios.
>
> Also, wrt rtmutex, will that top-spinner thing ever make it in?
Nah, tglx rewrote that a while ago. It's something semi clever now.
Lemme see if I can find the patch.
https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/commit/kernel/locking/rwsem-rt.c?h=linux-4.18.y-rt&id=1a42d0b3c3f34895cb5d63e1cd2be02f6077919b
next prev parent reply other threads:[~2018-09-11 19:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 20:18 Waiman Long
2018-09-10 9:31 ` Peter Zijlstra
2018-09-10 15:01 ` Waiman Long
2018-09-10 17:15 ` Davidlohr Bueso
2018-09-10 17:35 ` Waiman Long
2018-09-11 8:17 ` Peter Zijlstra
2018-09-11 12:56 ` Waiman Long
2018-09-11 19:21 ` Davidlohr Bueso
2018-09-11 19:38 ` Peter Zijlstra [this message]
2018-09-10 10:54 ` [tip:locking/core] " tip-bot for Waiman Long
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