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From: Aaro Koskinen <aaro.koskinen@iki.fi>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	James Morse <james.morse@arm.com>,
	Jayachandran Chandrasekharan Nair <jnair@marvell.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>,
	linux-arm-kernel@lists.infradead.org,
	Aaro Koskinen <aaro.koskinen@iki.fi>
Subject: [PATCH v2 1/2] arm64: Improve parking of stopped CPUs
Date: Mon, 17 Jun 2019 23:35:18 +0300
Message-ID: <20190617203519.328-1-aaro.koskinen@iki.fi> (raw)

From: Jayachandran C <jnair@caviumnetworks.com>

The current code puts the stopped cpus in an 'yield' instruction loop.
Using a busy loop here is unnecessary, we can use the cpu_park_loop()
function here to do a wfi/wfe.

Signed-off-by: Jayachandran C <jnair@caviumnetworks.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Will Deacon <will.deacon@arm.com>
---

	v2: Add Acked-by

	v1: https://patchwork.kernel.org/patch/10988099/

 arch/arm64/kernel/smp.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index bb4b3f07761a..1a1b96a50245 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -854,9 +854,7 @@ static void ipi_cpu_stop(unsigned int cpu)
 
 	local_daif_mask();
 	sdei_mask_local_cpu();
-
-	while (1)
-		cpu_relax();
+	cpu_park_loop();
 }
 
 #ifdef CONFIG_KEXEC_CORE
-- 
2.17.0


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Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 20:35 Aaro Koskinen [this message]
2019-06-17 20:35 ` [PATCH v2 2/2] arm64: Implement panic_smp_self_stop() Aaro Koskinen
2019-06-18 12:51   ` Will Deacon
2019-06-25 15:43 ` [PATCH v2 1/2] arm64: Improve parking of stopped CPUs Catalin Marinas

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