From: Torsten Duwe <duwe@lst.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] Convert powerpc simple spinlocks into ticket locks
Date: Fri, 7 Feb 2014 09:24:37 +0100 [thread overview]
Message-ID: <20140207082437.GA26811@lst.de> (raw)
In-Reply-To: <20140206180826.GI5002@laptop.programming.kicks-ass.net>
On Thu, Feb 06, 2014 at 07:08:26PM +0100, Peter Zijlstra wrote:
> On Thu, Feb 06, 2014 at 06:37:27PM +0100, Torsten Duwe wrote:
> > I must admit that I haven't tested the patch on non-pseries ppc64 nor on
> > ppc32. Only ppc64 has the ldarx and I tried to atomically replace the
> > holder along with the locks. That might prove unneccessary.
>
> But what is the holder for? Can't we do away with that field?
Scott, Peter: good questions.
The conditional is wrong because I confused pSeries with ppc64 CPUs with
64-bit kernels. I got deluded by the LOCK_TOKEN definition above. Is that
correctly ifdef'd, with PPC64? The holder field should be ifdef'd
CONFIG_PPC_SPLPAR, independent of ppc64.
It is an advisory performance hint, and doesn't need to be updated atomically
with the lock; this and the above are 2 reasons to drop the asm string
operand size voodoo as well.
Thanks,
Torsten
next prev parent reply other threads:[~2014-02-07 8:24 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-06 10:37 [PATCH] Convert powerpc simple spinlocks into ticket locks Torsten Duwe
2014-02-06 15:53 ` Benjamin Herrenschmidt
2014-02-06 16:38 ` Peter Zijlstra
2014-02-06 17:37 ` Torsten Duwe
2014-02-06 18:08 ` Peter Zijlstra
2014-02-06 19:28 ` Tom Musta
2014-02-10 2:54 ` Benjamin Herrenschmidt
2014-02-07 8:24 ` Torsten Duwe [this message]
2014-02-06 20:19 ` Scott Wood
2014-02-07 9:02 ` Torsten Duwe
2014-02-07 10:31 ` Peter Zijlstra
2014-02-07 10:36 ` Peter Zijlstra
2014-02-07 10:45 ` Peter Zijlstra
2014-02-07 11:49 ` Torsten Duwe
2014-02-07 12:28 ` Peter Zijlstra
2014-02-07 15:18 ` Peter Zijlstra
2014-02-07 15:43 ` Peter Zijlstra
2014-02-07 17:08 ` Torsten Duwe
2014-02-07 17:19 ` Peter Zijlstra
2014-02-07 15:51 ` Kumar Gala
2014-02-07 16:10 ` Peter Zijlstra
2014-02-10 3:05 ` Benjamin Herrenschmidt
2014-02-10 3:02 ` Benjamin Herrenschmidt
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