From: Michael Ellerman <mpe@ellerman.id.au>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH for-4.17 2/2] powerpc: Remove smp_mb() from arch_spin_is_locked()
Date: Wed, 04 Apr 2018 20:28:36 +1000 [thread overview]
Message-ID: <87tvsrmfjf.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20180328110809.GE4129@hirez.programming.kicks-ass.net>
Peter Zijlstra <peterz@infradead.org> writes:
> On Wed, Mar 28, 2018 at 01:04:36PM +0200, Peter Zijlstra wrote:
>> On Wed, Mar 28, 2018 at 04:25:37PM +1100, Michael Ellerman wrote:
>> > Documenting it would definitely be good, but even then I'd be inclined
>> > to leave the barrier in our implementation. Matching the documented
>> > behaviour is one thing, but the actual real-world behaviour on well
>> > tested platforms (ie. x86) is more important.
>>
>> By that argument you should switch your spinlock implementation to RCpc
>> and include that SYNC in either lock or unlock already ;-)
>
> *RCsc* obviously... clearly I need to wake up moar.
It's just a jumble of letters to me - I didn't even notice ;)
cheers
next prev parent reply other threads:[~2018-04-04 10:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-26 10:37 [PATCH for-4.17 2/2] powerpc: Remove smp_mb() from arch_spin_is_locked() Andrea Parri
2018-03-27 0:06 ` Benjamin Herrenschmidt
2018-03-27 10:25 ` Andrea Parri
2018-03-27 11:33 ` Benjamin Herrenschmidt
2018-03-27 13:13 ` Andrea Parri
2018-03-27 21:51 ` Benjamin Herrenschmidt
2018-03-28 9:17 ` Andrea Parri
2018-03-28 5:25 ` Michael Ellerman
2018-03-28 11:04 ` Peter Zijlstra
2018-03-28 11:08 ` Peter Zijlstra
2018-04-04 10:28 ` Michael Ellerman [this message]
2018-04-04 10:28 ` Michael Ellerman
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