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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>,
	linux-kernel@vger.kernel.org,
	linux-s390 <linux-s390@vger.kernel.org>,
	linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Noam Camus <noamc@ezchip.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Subject: [PATCH 3/5] s390: make cpu_relax a barrier again
Date: Fri, 21 Oct 2016 13:58:56 +0200	[thread overview]
Message-ID: <1477051138-1610-4-git-send-email-borntraeger@de.ibm.com> (raw)
In-Reply-To: <1477051138-1610-1-git-send-email-borntraeger@de.ibm.com>

stop_machine seems to be the only important place for yielding during
cpu_relax. This was fixed by using cpu_relax_yield. Therefore, we can
now redefine cpu_relax to be a barrier instead. (With the option to do
some SMT tuning later on)

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/include/asm/processor.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index d05965b..5d262cf 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -236,7 +236,7 @@ static inline unsigned short stap(void)
  */
 void cpu_relax_yield(void);
 
-#define cpu_relax() cpu_relax_yield()
+#define cpu_relax() barrier()
 #define cpu_relax_lowlatency()  barrier()
 
 #define ECAG_CACHE_ATTRIBUTE	0
-- 
2.5.5

  parent reply	other threads:[~2016-10-21 11:59 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-21 11:58 [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency Christian Borntraeger
2016-10-21 11:58 ` [PATCH 1/5] processor.h: introduce cpu_relax_yield Christian Borntraeger
2016-10-21 11:58 ` [PATCH 2/5] stop_machine: yield CPU during stop machine Christian Borntraeger
2016-10-21 12:05   ` Peter Zijlstra
2016-10-21 12:41     ` Juergen Gross
2016-10-22  0:06     ` Nicholas Piggin
2016-10-24  7:52       ` Christian Borntraeger
2016-10-24  8:47         ` Peter Zijlstra
2016-10-21 11:58 ` Christian Borntraeger [this message]
2016-10-21 11:58 ` [PATCH 4/5] Remove cpu_relax_lowlatency users Christian Borntraeger
2016-10-21 11:58 ` [PATCH 5/5] remove cpu_relax_lowlatency Christian Borntraeger
2016-10-21 12:06 ` [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency Peter Zijlstra
2016-10-21 14:57 ` David Miller
2016-10-21 15:08   ` Christian Borntraeger
2016-10-21 15:12     ` David Miller

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