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From: Valentin Schneider <valentin.schneider@arm.com>
To: linux-kernel@vger.kernel.org
Cc: Russell King <linux@armlinux.org.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will.deacon@arm.com>,
	Julien Thierry <julien.thierry@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 2/3] ARM: entry: Remove unneeded need_resched() loop
Date: Thu, 31 Jan 2019 18:23:38 +0000	[thread overview]
Message-ID: <20190131182339.9835-3-valentin.schneider@arm.com> (raw)
In-Reply-To: <20190131182339.9835-1-valentin.schneider@arm.com>

Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm/kernel/entry-armv.S | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index e85a3af9ddeb..a7ac22e09bb2 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -220,7 +220,7 @@ __irq_svc:
 	teq	r8, #0				@ if preempt count != 0
 	movne	r0, #0				@ force flags to 0
 	tst	r0, #_TIF_NEED_RESCHED
-	blne	svc_preempt
+	blne	preempt_schedule_irq            @ irq en/disable is done inside
 #endif
 
 	svc_exit r5, irq = 1			@ return from exception
@@ -229,16 +229,6 @@ ENDPROC(__irq_svc)
 
 	.ltorg
 
-#ifdef CONFIG_PREEMPT
-svc_preempt:
-	mov	r8, lr
-1:	bl	preempt_schedule_irq		@ irq en/disable is done inside
-	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS
-	tst	r0, #_TIF_NEED_RESCHED
-	reteq	r8				@ go again
-	b	1b
-#endif
-
 __und_fault:
 	@ Correct the PC such that it is pointing at the instruction
 	@ which caused the fault.  If the faulting instruction was ARM
-- 
2.20.1


WARNING: multiple messages have this Message-ID (diff)
From: Valentin Schneider <valentin.schneider@arm.com>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will.deacon@arm.com>,
	Russell King <linux@armlinux.org.uk>,
	linux-arm-kernel@lists.infradead.org,
	Julien Thierry <julien.thierry@arm.com>
Subject: [RFC PATCH 2/3] ARM: entry: Remove unneeded need_resched() loop
Date: Thu, 31 Jan 2019 18:23:38 +0000	[thread overview]
Message-ID: <20190131182339.9835-3-valentin.schneider@arm.com> (raw)
In-Reply-To: <20190131182339.9835-1-valentin.schneider@arm.com>

Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm/kernel/entry-armv.S | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index e85a3af9ddeb..a7ac22e09bb2 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -220,7 +220,7 @@ __irq_svc:
 	teq	r8, #0				@ if preempt count != 0
 	movne	r0, #0				@ force flags to 0
 	tst	r0, #_TIF_NEED_RESCHED
-	blne	svc_preempt
+	blne	preempt_schedule_irq            @ irq en/disable is done inside
 #endif
 
 	svc_exit r5, irq = 1			@ return from exception
@@ -229,16 +229,6 @@ ENDPROC(__irq_svc)
 
 	.ltorg
 
-#ifdef CONFIG_PREEMPT
-svc_preempt:
-	mov	r8, lr
-1:	bl	preempt_schedule_irq		@ irq en/disable is done inside
-	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS
-	tst	r0, #_TIF_NEED_RESCHED
-	reteq	r8				@ go again
-	b	1b
-#endif
-
 __und_fault:
 	@ Correct the PC such that it is pointing at the instruction
 	@ which caused the fault.  If the faulting instruction was ARM
-- 
2.20.1


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  parent reply	other threads:[~2019-01-31 18:24 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-31 18:23 [RFC PATCH 0/3] arm/arm64: entry: Remove need_resched() loop Valentin Schneider
2019-01-31 18:23 ` Valentin Schneider
2019-01-31 18:23 ` [RFC PATCH 1/3] arm64: entry: Remove unneeded " Valentin Schneider
2019-01-31 18:23   ` Valentin Schneider
2019-02-01  8:46   ` Julien Thierry
2019-02-01  8:46     ` Julien Thierry
2019-02-01 10:21   ` Will Deacon
2019-02-01 10:21     ` Will Deacon
2019-02-04 16:55   ` Catalin Marinas
2019-02-04 16:55     ` Catalin Marinas
2019-01-31 18:23 ` Valentin Schneider [this message]
2019-01-31 18:23   ` [RFC PATCH 2/3] ARM: " Valentin Schneider
2019-02-01  8:49   ` Julien Thierry
2019-02-01  8:49     ` Julien Thierry
2019-01-31 18:23 ` [RFC PATCH 3/3] sched/Documentation: Point out use of preempt_schedule_irq() Valentin Schneider
2019-02-01  8:45   ` Julien Thierry
2019-02-01 10:27     ` Valentin Schneider

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