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| Started by | Anna-Maria Gleixner <anna-maria@linutronix.de> |
|---|---|
| First post | 2016-04-04 12:30 +0200 |
| Last post | 2016-04-05 13:00 +0200 |
| Articles | 2 — 2 participants |
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[PATCH] s390/cpum_cf: Remove superfluous SMP function call Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-04-04 12:30 +0200
Re: [PATCH] s390/cpum_cf: Remove superfluous SMP function call Heiko Carstens <heiko.carstens@de.ibm.com> - 2016-04-05 13:00 +0200
| From | Anna-Maria Gleixner <anna-maria@linutronix.de> |
|---|---|
| Date | 2016-04-04 12:30 +0200 |
| Subject | [PATCH] s390/cpum_cf: Remove superfluous SMP function call |
| Message-ID | <rk9VH-1Ap-83@gated-at.bofh.it> |
Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and
CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
function calls are no longer required.
Replace smp_call_function_single() with a direct call of
setup_pmc_cpu(). To keep the calling convention, interrupts are
explicitely disabled around the call.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
arch/s390/kernel/perf_cpum_cf.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -665,18 +665,21 @@ static struct pmu cpumf_pmu = {
static int cpumf_pmu_notifier(struct notifier_block *self, unsigned long action,
void *hcpu)
{
- unsigned int cpu = (long) hcpu;
int flags;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
case CPU_DOWN_FAILED:
flags = PMC_INIT;
- smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
+ local_irq_disable();
+ setup_pmc_cpu(&flags);
+ local_irq_enable();
break;
case CPU_DOWN_PREPARE:
flags = PMC_RELEASE;
- smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
+ local_irq_disable();
+ setup_pmc_cpu(&flags);
+ local_irq_enable();
break;
default:
break;
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| From | Heiko Carstens <heiko.carstens@de.ibm.com> |
|---|---|
| Date | 2016-04-05 13:00 +0200 |
| Message-ID | <rkwSe-1Ul-23@gated-at.bofh.it> |
| In reply to | #1370528 |
On Mon, Apr 04, 2016 at 12:27:45PM +0200, Anna-Maria Gleixner wrote:
> Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
> hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and
> CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
> function calls are no longer required.
>
> Replace smp_call_function_single() with a direct call of
> setup_pmc_cpu(). To keep the calling convention, interrupts are
> explicitely disabled around the call.
>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: linux-s390@vger.kernel.org
> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
> ---
> arch/s390/kernel/perf_cpum_cf.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> --- a/arch/s390/kernel/perf_cpum_cf.c
> +++ b/arch/s390/kernel/perf_cpum_cf.c
> @@ -665,18 +665,21 @@ static struct pmu cpumf_pmu = {
> static int cpumf_pmu_notifier(struct notifier_block *self, unsigned long action,
> void *hcpu)
> {
> - unsigned int cpu = (long) hcpu;
> int flags;
>
> switch (action & ~CPU_TASKS_FROZEN) {
> case CPU_ONLINE:
> case CPU_DOWN_FAILED:
> flags = PMC_INIT;
> - smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
> + local_irq_disable();
> + setup_pmc_cpu(&flags);
> + local_irq_enable();
> break;
Same issue about CPU_DOWN_FAILED here.
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