From: Peter Zijlstra <peterz@infradead.org>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: mingo@kernel.org, oleg@redhat.com, linux-kernel@vger.kernel.org,
paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com, corbet@lwn.net,
mhocko@kernel.org, dhowells@redhat.com,
torvalds@linux-foundation.org, will.deacon@arm.com,
waiman.long@hpe.com, pjt@google.com
Subject: Re: [PATCH 3/4] locking: Introduce smp_cond_acquire()
Date: Thu, 3 Dec 2015 21:31:59 +0100 [thread overview]
Message-ID: <20151203203159.GW17308@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20151203194139.GA5650@linux-uzut.site>
On Thu, Dec 03, 2015 at 11:41:39AM -0800, Davidlohr Bueso wrote:
> >+#define smp_cond_acquire(cond) do { \
> >+ while (!(cond)) \
> >+ cpu_relax(); \
> >+ smp_rmb(); /* ctrl + rmb := acquire */ \
> >+} while (0)
>
> So this hides the fact that we actually are waiting on the cond, as opposed
> to conditional acquiring. Could it be renamed to something like smp_waitcond_acquire()?
Right, I'm conflicted about that. On the one hand you're right, on the
other hand we spin-wait so the next person will want it called
smp_spin_wait_cond_acquire(), also it gets terribly long either way :/
bike-shed away I imagine.
next prev parent reply other threads:[~2015-12-03 20:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-03 12:40 [PATCH 0/4] scheduler ordering bits -v2 Peter Zijlstra
2015-12-03 12:40 ` [PATCH 1/4] sched: Better document the try_to_wake_up() barriers Peter Zijlstra
2015-12-03 12:40 ` [PATCH 2/4] sched: Fix a race in try_to_wake_up() vs schedule() Peter Zijlstra
2015-12-03 12:40 ` [PATCH 3/4] locking: Introduce smp_cond_acquire() Peter Zijlstra
2015-12-03 16:37 ` Will Deacon
2015-12-03 20:26 ` Peter Zijlstra
2015-12-03 21:16 ` Peter Zijlstra
2015-12-04 14:57 ` Will Deacon
2015-12-04 20:51 ` Waiman Long
2015-12-04 22:05 ` Linus Torvalds
2015-12-04 22:48 ` Waiman Long
2015-12-04 23:43 ` Peter Zijlstra
2015-12-07 15:18 ` Will Deacon
2015-12-03 19:41 ` Davidlohr Bueso
2015-12-03 20:31 ` Peter Zijlstra [this message]
2015-12-03 12:40 ` [PATCH 4/4] sched: Document Program-Order guarantees Peter Zijlstra
2015-12-03 13:16 ` Boqun Feng
2015-12-03 13:29 ` Peter Zijlstra
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