From: Will Deacon <will.deacon@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <Waiman.Long@hp.com>,
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" <linux-arch@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.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>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.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 Chandramouleeswaran\"" <aswin@hp.com>,
Scott J Norton <scott.norton@hp.com>,
"will@willdeacon.co.uk" <will@willdeacon.co.uk>
Subject: Re: [PATCH v11 0/4] Introducing a queue read/write lock implementation
Date: Thu, 30 Jan 2014 18:11:36 +0000 [thread overview]
Message-ID: <20140130181136.GP7575@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <20140130180533.GH5002@laptop.programming.kicks-ass.net>
On Thu, Jan 30, 2014 at 06:05:33PM +0000, Peter Zijlstra wrote:
> On Thu, Jan 30, 2014 at 05:52:12PM +0000, Will Deacon wrote:
> > It would be nice if these were default implementations of the unlock, then
> > architectures just implement atomic_sub_release how they like.
>
> Yes, I suppose that makes sense. Last time I proposed the primitive
> nobody yelled at me, so I suppose that means people agree :-)
If it's useful for these qrwlocks, that's good enough for me!
> > One thing worth mentioning: I have a fairly invasive set of changes pending
> > for arch/arm64/include/asm/atomic.h, so if you do decide to go with this,
> > I'm more than happy to take the sub_release part via the arm64 tree. I guess
> > it depends on when this is likely to get merged.
>
> I suppose it depends on when I get enough courage to do: vim
> arch/*/include/asm/atomic*.h :-)
Hehe.
> There's a few other cleanups I want to do, like today I found
> atomic_{set,clear}_mask() instead of the more natural atomic_{or,and}()
> functions.
Have you looked at the OpenCL atomic intrinsics at all?
http://www.khronos.org/registry/cl/sdk/1.2/docs/man/xhtml/atomicFunctions.html
There's a good chance that they can be implemented efficiently on any
architectures that care about OpenCL. As you've noticed, composing them
together can be more efficient on LL/SC-based architectures too.
> I also think we can get rid of the {inc,dec} variants of
> smp_mb__{before,after}_atomic() since these barriers should be the same
> for _all_ atomic ops that do not already imply full mb semantics, and
> they're certainly the same for all current inc/dec.
Makes sense.
> If tomorrow is another slow day and I get through enough of the review
> backlog I might just give it a go.
>
> Anyway, I'll base them on your arm64 changes, I know where to find
> those.
Okey doke. If you need a stable (non-rebasing) branch, just holler.
Cheers,
Will
next prev parent reply other threads:[~2014-01-30 18:13 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-24 4:28 [PATCH v11 0/4] Introducing a queue read/write lock implementation Waiman Long
2014-01-24 4:28 ` [PATCH v11 1/4] qrwlock: A " Waiman Long
2014-01-24 8:25 ` Peter Zijlstra
2014-01-25 4:39 ` Waiman Long
2014-01-24 4:28 ` [PATCH v11 2/4] qrwlock, x86: Enable x86 to use queue read/write lock Waiman Long
2014-01-24 4:28 ` [PATCH v11 3/4] qrwlock, x86: Add char and short as atomic data type in x86 Waiman Long
2014-01-24 4:28 ` [PATCH v11 4/4] qrwlock: Use the mcs_spinlock helper functions for MCS queuing Waiman Long
2014-01-24 8:26 ` Peter Zijlstra
2014-01-25 4:30 ` Waiman Long
2014-01-30 13:04 ` [PATCH v11 0/4] Introducing a queue read/write lock implementation Peter Zijlstra
2014-01-30 15:17 ` Peter Zijlstra
2014-01-30 15:43 ` Waiman Long
2014-01-30 15:50 ` Waiman Long
2014-01-30 15:53 ` Peter Zijlstra
2014-01-30 15:44 ` Peter Zijlstra
2014-01-30 17:52 ` Will Deacon
2014-01-30 18:05 ` Peter Zijlstra
2014-01-30 18:11 ` Will Deacon [this message]
2014-01-30 18:16 ` Peter Zijlstra
2014-01-31 9:26 ` Peter Zijlstra
2014-01-31 10:03 ` George Spelvin
2014-01-31 10:17 ` Peter Zijlstra
2014-01-31 11:30 ` Peter Zijlstra
2014-02-01 23:22 ` Paul E. McKenney
2014-01-31 18:59 ` Waiman Long
2014-01-31 19:47 ` Peter Zijlstra
2014-02-01 10:38 ` George Spelvin
2014-01-31 20:14 ` Peter Zijlstra
2014-01-31 21:09 ` Waiman Long
2014-02-01 1:29 ` Davidlohr Bueso
2014-02-02 9:03 ` Ingo Molnar
2014-02-03 11:38 ` Peter Zijlstra
2014-02-06 3:08 ` Waiman Long
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