Re: [PATCH 20/36] arch/idle: Change arch_cpu_idle() IRQ behaviour
ieu.desnoy...@efficios.com>, Frederic Weisbecker , Len
Brown , linux-xte...@linux-xtensa.org, Sascha Hauer
, Vasily Gorbik , linux-arm-msm
, linux-al...@vger.kernel.org, linux-m68k
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, Chris Zankel ,
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, Lorenzo Pieralisi
, Rasmus Villemoes , Joel
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, Arnd Bergmann , ulli.kr...@googlemail.com,
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, Steven Rostedt ,
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, Sudeep Holla , Shawn Guo
, David Miller , Rich Felker
, Tony Lindgren , amakha...@vmware.com,
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, sparcli...@vger.kernel.org, linux-hexa...@vger.kernel.org,
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, the arch/x86 maintainers , Russell King -
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, linux-tegra ,
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, "open list:BROADCOM NVRAM DRIVER"
, Palmer Dabbelt , Anup Patel
, i...@jurassic.park.msu.ru, Johannes Berg
, linuxppc-dev
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On Wed, Jun 8, 2022 at 4:46 PM Peter Zijlstra wrote:
>
> Current arch_cpu_idle() is called with IRQs disabled, but will return
> with IRQs enabled.
>
> However, the very first thing the generic code does after calling
> arch_cpu_idle() is raw_local_irq_disable(). This means that
> architectures that can idle with IRQs disabled end up doing a
> pointless 'enable-disable' dance.
>
> Therefore, push this IRQ disabling into the idle function, meaning
> that those architectures can avoid the pointless IRQ state flipping.
>
> Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Rafael J. Wysocki
> ---
> arch/alpha/kernel/process.c |1 -
> arch/arc/kernel/process.c|3 +++
> arch/arm/kernel/process.c|1 -
> arch/arm/mach-gemini/board-dt.c |3 ++-
> arch/arm64/kernel/idle.c |1 -
> arch/csky/kernel/process.c |1 -
> arch/csky/kernel/smp.c |2 +-
> arch/hexagon/kernel/process.c|1 -
> arch/ia64/kernel/process.c |1 +
> arch/microblaze/kernel/process.c |1 -
> arch/mips/kernel/idle.c |8 +++-
> arch/nios2/kernel/process.c |1 -
> arch/openrisc/kernel/process.c |1 +
> arch/parisc/kernel/process.c |2 --
> arch/powerpc/kernel/idle.c |5 ++---
> arch/riscv/kernel/process.c |1 -
> arch/s390/kernel/idle.c |1 -
> arch/sh/kernel/idle.c|1 +
> arch/sparc/kernel/leon_pmc.c |4
> arch/sparc/kernel/process_32.c |1 -
> arch/sparc/kernel/process_64.c |3 ++-
> arch/um/kernel/process.c |1 -
> arch/x86/coco/tdx/tdx.c |3 +++
> arch/x86/kernel/process.c| 15 ---
> arch/xtensa/kernel/process.c |1 +
> kernel/sched/idle.c |2 --
> 26 files changed, 28 insertions(+), 37 deletions(-)
>
> --- a/arch/alpha/kernel/process.c
> +++ b/arch/alpha/kernel/process.c
> @@ -57,7 +57,6 @@ EXPORT_SYMBOL(pm_power_off);
> void arch_cpu_idle(void)
> {
> wtint(0);
> - raw_local_irq_enable();
> }
>
> void arch_cpu_idle_dead(void)
> --- a/arch/arc/kernel/process.c
> +++ b/arch/arc/kernel/process.c
> @@ -114,6 +114,8 @@ void arch_cpu_idle(void)
> "sleep %0 \n"
> :
> :"I"(arg)); /* can't be "r" has to be embedded const */
> +
> + raw_local_irq_disable();
> }
>
> #else /* ARC700 */
> @@ -122,6 +124,7 @@ void arch_cpu_idle(void)
> {
> /* sleep, but enable both set E1/E2 (levels of interrupts) before
> committing */
> __asm__ __volatile__("sleep 0x3 \n");
> + raw_local_irq_disable();
> }
>
> #endif
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -78,7 +78,6 @@ void arch_cpu_idle(void)
> arm_pm_idle();
> else
> cpu_do_idle();
> - raw_local_irq_enable();
> }
>
> void arch_cpu_idle_prepare(void)
> --- a/arch/arm/mach-gemini/board-dt.c
> +++ b/arch/arm/mach-gemini/board-dt.c
> @@ -42,8 +42,9 @@ static void gemini_idle(void)
> */
>
> /* FIXME: Enabling interrupts here is racy! */
> - local_irq_enable();
> + raw_local_irq_enable();
> cpu_do_idle();
> + raw_local_irq_disable();
> }
>
> static void __init gemini_init_machine(void)
> --- a/arch/arm64/kernel/idle.c
> +++
Re: [PATCH 20/36] arch/idle: Change arch_cpu_idle() IRQ behaviour
arndb.de>, ulli.kr...@googlemail.com, vgu...@kernel.org,
linux-...@vger.kernel.org, j...@joshtriplett.org, rost...@goodmis.org,
r...@vger.kernel.org, b...@alien8.de, bc...@quicinc.com,
tsbog...@alpha.franken.de, linux-par...@vger.kernel.org, sudeep.ho...@arm.com,
shawn...@kernel.org, da...@davemloft.net, dal...@libc.org, t...@atomide.com,
amakha...@vmware.com, bjorn.anders...@linaro.org, h...@zytor.com,
sparcli...@vger.kernel.org, linux-hexa...@vger.kernel.org,
linux-ri...@lists.infradead.org, anton.iva...@cambridgegreys.com,
jo...@southpole.se, yury.no...@gmail.com, rich...@nod.at, x...@kernel.org,
li...@armlinux.org.uk, mi...@redhat.com, a...@eecs.berkeley.edu,
paul...@kernel.org, h...@linux.ibm.com, stefan.kristians...@saunalahti.fi,
openr...@lists.librecores.org, paul.walms...@sifive.com,
linux-te...@vger.kernel.org, namhy...@kernel.org,
andriy.shevche...@linux.intel.com, jpoim...@kernel.org, jgr...@suse.com,
mon...@monstr.eu, linux-m...@vger.kernel.org, pal...@dabbelt.com, anup@brainfa
ult.org, i...@jurassic.park.msu.ru, johan...@sipsolutions.net,
linuxppc-dev@lists.ozlabs.org
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On Wed, Jun 08, 2022 at 04:27:43PM +0200, Peter Zijlstra wrote:
> Current arch_cpu_idle() is called with IRQs disabled, but will return
> with IRQs enabled.
>
> However, the very first thing the generic code does after calling
> arch_cpu_idle() is raw_local_irq_disable(). This means that
> architectures that can idle with IRQs disabled end up doing a
> pointless 'enable-disable' dance.
>
> Therefore, push this IRQ disabling into the idle function, meaning
> that those architectures can avoid the pointless IRQ state flipping.
>
> Signed-off-by: Peter Zijlstra (Intel)
Nice!
Acked-by: Mark Rutland [arm64]
Mark.
> ---
> arch/alpha/kernel/process.c |1 -
> arch/arc/kernel/process.c|3 +++
> arch/arm/kernel/process.c|1 -
> arch/arm/mach-gemini/board-dt.c |3 ++-
> arch/arm64/kernel/idle.c |1 -
> arch/csky/kernel/process.c |1 -
> arch/csky/kernel/smp.c |2 +-
> arch/hexagon/kernel/process.c|1 -
> arch/ia64/kernel/process.c |1 +
> arch/microblaze/kernel/process.c |1 -
> arch/mips/kernel/idle.c |8 +++-
> arch/nios2/kernel/process.c |1 -
> arch/openrisc/kernel/process.c |1 +
> arch/parisc/kernel/process.c |2 --
> arch/powerpc/kernel/idle.c |5 ++---
> arch/riscv/kernel/process.c |1 -
> arch/s390/kernel/idle.c |1 -
> arch/sh/kernel/idle.c|1 +
> arch/sparc/kernel/leon_pmc.c |4
> arch/sparc/kernel/process_32.c |1 -
> arch/sparc/kernel/process_64.c |3 ++-
> arch/um/kernel/process.c |1 -
> arch/x86/coco/tdx/tdx.c |3 +++
> arch/x86/kernel/process.c| 15 ---
> arch/xtensa/kernel/process.c |1 +
> kernel/sched/idle.c |2 --
> 26 files changed, 28 insertions(+), 37 deletions(-)
>
> --- a/arch/alpha/kernel/process.c
> +++ b/arch/alpha/kernel/process.c
> @@ -57,7 +57,6 @@ EXPORT_SYMBOL(pm_power_off);
> void arch_cpu_idle(void)
> {
> wtint(0);
> - raw_local_irq_enable();
> }
>
> void arch_cpu_idle_dead(void)
> --- a/arch/arc/kernel/process.c
> +++ b/arch/arc/kernel/process.c
> @@ -114,6 +114,8 @@ void arch_cpu_idle(void)
> "sleep %0 \n"
> :
> :"I"(arg)); /* can't be "r" has to be embedded const */
> +
> + raw_local_irq_disable();
> }
>
> #else/* ARC700 */
> @@ -122,6 +124,7 @@ void arch_cpu_idle(void)
> {
> /* sleep, but enable both set E1/E2 (levels of interrupts) before
> committing */
> __asm__ __volatile__("sleep 0x3 \n");
> + raw_local_irq_disable();
> }
>
> #endif
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -78,7 +78,6 @@ void arch_cpu_idle(void)
> arm_pm_idle();
> else
> cpu_do_idle();
> - raw_local_irq_enable();
> }
>
> void arch_cpu_idle_prepare(void)
> --- a/arch/arm/mach-gemini/board-dt.c
> +++ b/arch/arm/mach-gemini/board-dt.c
> @@ -42,8 +42,9 @@ static void gemini_idle(void)
>*/
>
> /* FIXME: Enabling interrupts here is racy! */
> - local_irq_enable();
> + raw_local_irq_enable();
> cpu_do_idle();
> + raw_local_irq_disable();
> }
>
> static void __init gemini_init_machine(void)
> --- a/arch/arm64/kernel/idle.c
> +++ b/arch/arm64/kernel/idle.c
> @@ -42,5 +42,4 @@ void noinstr arch_cpu_idle(void)
>* tricks
>*/
> cpu_do_idle();
> - raw_local_irq_enable();
> }
> --- a/arch/csky/kernel/process.c
> +++ b/arch/csky/kernel/process.c
> @@ -101,6 +101,5 @@ void arch_cpu_idle(void)
> #ifdef CONFIG_CPU_PM_STOP
> asm volatile("stop\n");
> #endif
> - raw_local_irq_enable();
> }
>
Re: [PATCH 20/36] arch/idle: Change arch_cpu_idle() IRQ behaviour
o...@users.sourceforge.jp>, Linux-sh list , Fabio Estevam , Helge Deller , Daniel Lezcano , Jonathan Hunter , Mathieu Desnoyers , Frederic Weisbecker , Len Brown , "open list:TENSILICA XTENSA PORT \(xtensa\)" , Sascha Hauer , Vasily Gorbik , linux-arm-msm , alpha , linux-m68k , Stafford Horne , Linux ARM , Chris Zankel , Stephen Boyd , Dinh Nguyen , Daniel Bristot de Oliveira , Alexander Shishkin , lpieral...@kernel.org, Rasmus Villemoes , Joel Fernandes < j...@joelfernandes.org>, Will Deacon , Boris Ostrovsky , Kevin Hilman , linux-c...@vger.kernel.org, Pv-drivers , "open list:SYNOPSYS ARC ARCHITECTURE" , Mel Gorman , jacob.jun@linux.intel.com, Arnd Bergmann , Hans Ulli Kroll , Vineet Gupta , linux-clk , Josh Triplett , Steven Rostedt , r...@vger.kernel.org, Borislav Petkov , bc...@quicinc.com, Thomas Bogendoerfer , Parisc List , Sudeep Holla , Shawn Guo , David Miller , Rich Felker , Tony Lindgren , amakha...@vmware.com, Bjorn Andersson , "H. Peter Anvin" , sparclinux , "open l ist:QUALCOMM HEXAGON..." , linux-riscv , Anton Ivanov , Jonas Bonn , Yury Norov , Richard Weinberger , the arch/x86 maintainers , Russell King - ARM Linux , Ingo Molnar , Albert Ou , "Paul E. McKenney" , Heiko Carstens , Stefan Kristiansson , Openrisc , Paul Walmsley , "open list:TEGRA ARCHITECTURE SUPPORT" , Namhyung Kim , Andy Shevchenko , jpoim...@kernel.org, Juergen Gross , Michal Simek , "open list:BROADCOM NVRAM DRIVER" , Palmer Dabbelt , Anup Patel , Ivan Kokshaysky , Johannes Berg , linuxppc-dev Errors-To: linuxppc-dev-bounces+archive=mail-archive@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra wrote: > > Current arch_cpu_idle() is called with IRQs disabled, but will return > with IRQs enabled. > > However, the very first thing the generic code does after calling > arch_cpu_idle() is raw_local_irq_disable(). This means that > architectures that can idle with IRQs disabled end up doing a > pointless 'enable-disable' dance. > > Therefore, push this IRQ disabling into the idle function, meaning > that those architectures can avoid the pointless IRQ state flipping. > > Signed-off-by: Peter Zijlstra (Intel) I think you now need to add the a raw_local_irq_disable(); in loongarch as well. Arnd
[PATCH 20/36] arch/idle: Change arch_cpu_idle() IRQ behaviour
, Arnd Bergmann , ulli.kr...@googlemail.com, vgu...@kernel.org,
linux-...@vger.kernel.org, j...@joshtriplett.org, rost...@goodmis.org,
r...@vger.kernel.org, b...@alien8.de, bc...@quicinc.com,
tsbog...@alpha.franken.de, linux-par...@vger.kernel.org, sudeep.ho...@arm.com,
shawn...@kernel.org, da...@davemloft.net, dal...@libc.org, t...@atomide.com,
amakha...@vmware.com, bjorn.anders...@linaro.org, h...@zytor.com,
sparcli...@vger.kernel.org, linux-hexa...@vger.kernel.org,
linux-ri...@lists.infradead.org, anton.iva...@cambridgegreys.com,
jo...@southpole.se, yury.no...@gmail.com, rich...@nod.at, x...@kernel.org,
li...@armlinux.org.uk, mi...@redhat.com, a...@eecs.berkeley.edu,
paul...@kernel.org, h...@linux.ibm.com, stefan.kristians...@saunalahti.fi,
openr...@lists.librecores.org, paul.walms...@sifive.com,
linux-te...@vger.kernel.org, namhy...@kernel.org,
andriy.shevche...@linux.intel.com, jpoim...@kernel.org, jgr...@suse.com,
mon...@monstr.eu, linux-m...@vger.kernel.org, palmer@dab
belt.com, a...@brainfault.org, i...@jurassic.park.msu.ru,
johan...@sipsolutions.net, linuxppc-dev@lists.ozlabs.org
Errors-To: linuxppc-dev-bounces+archive=mail-archive@lists.ozlabs.org
Sender: "Linuxppc-dev"
Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.
However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.
Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.
Signed-off-by: Peter Zijlstra (Intel)
---
arch/alpha/kernel/process.c |1 -
arch/arc/kernel/process.c|3 +++
arch/arm/kernel/process.c|1 -
arch/arm/mach-gemini/board-dt.c |3 ++-
arch/arm64/kernel/idle.c |1 -
arch/csky/kernel/process.c |1 -
arch/csky/kernel/smp.c |2 +-
arch/hexagon/kernel/process.c|1 -
arch/ia64/kernel/process.c |1 +
arch/microblaze/kernel/process.c |1 -
arch/mips/kernel/idle.c |8 +++-
arch/nios2/kernel/process.c |1 -
arch/openrisc/kernel/process.c |1 +
arch/parisc/kernel/process.c |2 --
arch/powerpc/kernel/idle.c |5 ++---
arch/riscv/kernel/process.c |1 -
arch/s390/kernel/idle.c |1 -
arch/sh/kernel/idle.c|1 +
arch/sparc/kernel/leon_pmc.c |4
arch/sparc/kernel/process_32.c |1 -
arch/sparc/kernel/process_64.c |3 ++-
arch/um/kernel/process.c |1 -
arch/x86/coco/tdx/tdx.c |3 +++
arch/x86/kernel/process.c| 15 ---
arch/xtensa/kernel/process.c |1 +
kernel/sched/idle.c |2 --
26 files changed, 28 insertions(+), 37 deletions(-)
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -57,7 +57,6 @@ EXPORT_SYMBOL(pm_power_off);
void arch_cpu_idle(void)
{
wtint(0);
- raw_local_irq_enable();
}
void arch_cpu_idle_dead(void)
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -114,6 +114,8 @@ void arch_cpu_idle(void)
"sleep %0 \n"
:
:"I"(arg)); /* can't be "r" has to be embedded const */
+
+ raw_local_irq_disable();
}
#else /* ARC700 */
@@ -122,6 +124,7 @@ void arch_cpu_idle(void)
{
/* sleep, but enable both set E1/E2 (levels of interrupts) before
committing */
__asm__ __volatile__("sleep 0x3 \n");
+ raw_local_irq_disable();
}
#endif
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -78,7 +78,6 @@ void arch_cpu_idle(void)
arm_pm_idle();
else
cpu_do_idle();
- raw_local_irq_enable();
}
void arch_cpu_idle_prepare(void)
--- a/arch/arm/mach-gemini/board-dt.c
+++ b/arch/arm/mach-gemini/board-dt.c
@@ -42,8 +42,9 @@ static void gemini_idle(void)
*/
/* FIXME: Enabling interrupts here is racy! */
- local_irq_enable();
+ raw_local_irq_enable();
cpu_do_idle();
+ raw_local_irq_disable();
}
static void __init gemini_init_machine(void)
--- a/arch/arm64/kernel/idle.c
+++ b/arch/arm64/kernel/idle.c
@@ -42,5 +42,4 @@ void noinstr arch_cpu_idle(void)
* tricks
*/
cpu_do_idle();
- raw_local_irq_enable();
}
--- a/arch/csky/kernel/process.c
+++ b/arch/csky/kernel/process.c
@@ -101,6 +101,5 @@ void arch_cpu_idle(void)
#ifdef CONFIG_CPU_PM_STOP
asm volatile("stop\n");
#endif
- raw_local_irq_enable();
}
#endif
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -314,7 +314,7 @@ void arch_cpu_idle_dead(void)
while (!secondary_stack)
arch_cpu_idle();
- local_irq_disable();
+ raw_local_irq_disable();
asm volatile(
"mov
