From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Waiman Long <waiman.long@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michel Lespinasse <walken@google.com>,
Andi Kleen <andi@firstfloor.org>, Rik van Riel <riel@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
George Spelvin <linux@horizon.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
aswin@hp.com, Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v7 1/4] qrwlock: A queue read/write lock implementation
Date: Wed, 18 Dec 2013 10:59:10 -0800 [thread overview]
Message-ID: <20131218185910.GS19211@linux.vnet.ibm.com> (raw)
In-Reply-To: <52B1ED2D.3020000@hp.com>
On Wed, Dec 18, 2013 at 01:45:01PM -0500, Waiman Long wrote:
> On 12/17/2013 02:21 PM, Paul E. McKenney wrote:
[ . . . ]
> >>+ signal_next(lock,&node);
> >Good, this allows multiple readers to acquire the lock concurrently,
> >give or take memory latency compared to critical-section duration.
> >When the first writer shows up, it presumably spins on the lock word.
> >
>
> Yes, that was the intention. The first writer that shows up will
> block succeeding readers from getting the lock.
>
> BTW, what was the status of the TSO memory barrier patch? This patch
> has some partial dependency it.
I am hoping that it makes it into -tip soon, as I also have a patch that
depends on it.
Thanx, Paul
next prev parent reply other threads:[~2013-12-18 18:59 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-22 19:04 [PATCH v7 0/4] qrwlock: Introducing a queue read/write lock implementation Waiman Long
2013-11-22 19:04 ` [PATCH v7 1/4] qrwlock: A " Waiman Long
2013-11-22 19:14 ` Linus Torvalds
2013-11-22 20:35 ` Waiman Long
2013-11-22 21:14 ` Linus Torvalds
2013-12-17 19:21 ` Paul E. McKenney
2013-12-17 19:27 ` Linus Torvalds
2013-12-17 19:49 ` Paul E. McKenney
2013-12-18 18:51 ` Waiman Long
2013-12-18 19:38 ` Andi Kleen
2013-12-18 19:42 ` Andi Kleen
2013-12-18 19:46 ` Peter Zijlstra
2013-12-18 20:16 ` Andi Kleen
2013-12-18 18:45 ` Waiman Long
2013-12-18 18:45 ` Waiman Long
2013-12-18 18:59 ` Paul E. McKenney [this message]
2013-12-18 18:59 ` Paul E. McKenney
2013-12-18 19:16 ` Peter Zijlstra
2013-12-18 19:16 ` Peter Zijlstra
2013-11-22 19:04 ` [PATCH v7 2/4] qrwlock x86: Enable x86 to use queue read/write lock Waiman Long
2013-11-22 19:04 ` Waiman Long
2013-12-17 19:22 ` Paul E. McKenney
2013-11-22 19:04 ` [PATCH v7 3/4] qrwlock: Use the mcs_spinlock helper functions for MCS queuing Waiman Long
2013-12-17 19:23 ` Paul E. McKenney
2013-11-22 19:04 ` [PATCH v7 4/4] qrwlock: Use smp_store_release() in write_unlock() Waiman Long
2013-12-17 19:24 ` Paul E. McKenney
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