From: Peter Zijlstra <peterz@infradead.org>
To: Andrea Parri <andrea.parri@amarulasolutions.com>
Cc: Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org, Jan Stancek <jstancek@redhat.com>,
Waiman Long <longman@redhat.com>,
dbueso@suse.de, mingo@redhat.com, jade.alglave@arm.com,
paulmck@linux.vnet.ibm.com
Subject: Re: [PATCH 1/4] locking/rwsem: Add missing ACQUIRE to read_slowpath exit when queue is empty
Date: Mon, 29 Jul 2019 17:24:28 +0200 [thread overview]
Message-ID: <20190729152428.GH31398@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190719084956.GA6750@andrea>
On Fri, Jul 19, 2019 at 10:49:56AM +0200, Andrea Parri wrote:
> > @@ -1032,6 +1032,8 @@ rwsem_down_read_slowpath(struct rw_semap
> > */
> > if (adjustment && !(atomic_long_read(&sem->count) &
> > (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) {
> > + /* Provide lock ACQUIRE */
> > + smp_acquire__after_ctrl_dep();
>
> Does this also make the lock RCtso? Or maybe RCtso was already
> guaranteed (and I'm failing to see why)?
I didn't specifically look for that, but I suspect not, esp given the
next patch.
next prev parent reply other threads:[~2019-07-29 15:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-18 13:49 [PATCH 0/4] Various rwsem ACQUIRE fixes Peter Zijlstra
2019-07-18 13:49 ` [PATCH 1/4] locking/rwsem: Add missing ACQUIRE to read_slowpath exit when queue is empty Peter Zijlstra
2019-07-19 8:49 ` Andrea Parri
2019-07-29 15:24 ` Peter Zijlstra [this message]
2019-07-18 13:49 ` [PATCH 2/4] rwsem: Add missing ACQUIRE to read_slowpath sleep loop Peter Zijlstra
2019-07-18 17:13 ` Waiman Long
2019-07-18 13:49 ` [PATCH 3/4] tty/ldsem: Add missing ACQUIRE to read_failed " Peter Zijlstra
2019-07-18 13:49 ` [PATCH 4/4] rwsem: Add ACQUIRE comments Peter Zijlstra
2019-07-29 15:18 ` [PATCH 0/4] Various rwsem ACQUIRE fixes Davidlohr Bueso
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