* [PATCH 2/2] arm64: take onlined cpus into account when setting irq affinity in migrate_one_irq
@ 2014-08-27 9:30 byungchul.park
2014-08-27 10:40 ` Sudeep Holla
0 siblings, 1 reply; 3+ messages in thread
From: byungchul.park @ 2014-08-27 9:30 UTC (permalink / raw)
To: will.deacon; +Cc: sudeep.holla, catalin.marinas, linux-kernel, Byungchul Park
From: Byungchul Park <byungchul.park@lge.com>
This patch ensures that the cpu being offlined is not present in the affinity mask.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
arch/arm64/kernel/irq.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 473e5db..0c7b79e 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -87,6 +87,7 @@ static bool migrate_one_irq(struct irq_desc *desc)
{
struct irq_data *d = irq_desc_get_irq_data(desc);
const struct cpumask *affinity = d->affinity;
+ struct cpumask tmp_affinity;
struct irq_chip *c;
bool ret = false;
@@ -100,6 +101,14 @@ static bool migrate_one_irq(struct irq_desc *desc)
if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
affinity = cpu_online_mask;
ret = true;
+ } else {
+ /*
+ * when using forced irq_set_affinity we must ensure that the cpu
+ * being offlined is not present in the affinity mask, it may be
+ * selected as the target CPU otherwise
+ */
+ cpumask_and(&tmp_affinity, affinity, cpu_online_mask);
+ affinity = &tmp_affinity;
}
c = irq_data_get_irq_chip(d);
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] arm64: take onlined cpus into account when setting irq affinity in migrate_one_irq
2014-08-27 9:30 [PATCH 2/2] arm64: take onlined cpus into account when setting irq affinity in migrate_one_irq byungchul.park
@ 2014-08-27 10:40 ` Sudeep Holla
2014-08-28 7:00 ` byungchul park
0 siblings, 1 reply; 3+ messages in thread
From: Sudeep Holla @ 2014-08-27 10:40 UTC (permalink / raw)
To: byungchul.park, Will Deacon; +Cc: Sudeep Holla, Catalin Marinas, linux-kernel
On 27/08/14 10:30, byungchul.park@lge.com wrote:
> From: Byungchul Park <byungchul.park@lge.com>
>
> This patch ensures that the cpu being offlined is not present in the affinity mask.
>
I agree that this patch fixes the issue reported in [1] without
disabling forced set affinity mask. However Thomas responded yesterday
asking to disable it [2] on the original thread for ARM. I have
responded on the thread and waiting for feedback from rmk and tglx. I
would prefer to wait and align with ARM code if possible.
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
> arch/arm64/kernel/irq.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
> index 473e5db..0c7b79e 100644
> --- a/arch/arm64/kernel/irq.c
> +++ b/arch/arm64/kernel/irq.c
> @@ -87,6 +87,7 @@ static bool migrate_one_irq(struct irq_desc *desc)
> {
> struct irq_data *d = irq_desc_get_irq_data(desc);
> const struct cpumask *affinity = d->affinity;
> + struct cpumask tmp_affinity;
> struct irq_chip *c;
> bool ret = false;
>
> @@ -100,6 +101,14 @@ static bool migrate_one_irq(struct irq_desc *desc)
> if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
> affinity = cpu_online_mask;
> ret = true;
> + } else {
> + /*
> + * when using forced irq_set_affinity we must ensure that the cpu
> + * being offlined is not present in the affinity mask, it may be
> + * selected as the target CPU otherwise
> + */
> + cpumask_and(&tmp_affinity, affinity, cpu_online_mask);
In case we decide to retain forced set affinity, you can probably squash
this cpumask_and with the above cpumask_any_and.
> + affinity = &tmp_affinity;
> }
>
> c = irq_data_get_irq_chip(d);
>
Regards,
Sudeep
[1]
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/266785.html
[2]
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/281548.html
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] arm64: take onlined cpus into account when setting irq affinity in migrate_one_irq
2014-08-27 10:40 ` Sudeep Holla
@ 2014-08-28 7:00 ` byungchul park
0 siblings, 0 replies; 3+ messages in thread
From: byungchul park @ 2014-08-28 7:00 UTC (permalink / raw)
To: Sudeep Holla
Cc: byungchul.park, Will Deacon, Catalin Marinas, linux-kernel, tglx
On Wed, Aug 27, 2014 at 7:40 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
>
> On 27/08/14 10:30, byungchul.park@lge.com wrote:
>>
>> From: Byungchul Park <byungchul.park@lge.com>
>>
>> This patch ensures that the cpu being offlined is not present in the
>> affinity mask.
>>
>
> I agree that this patch fixes the issue reported in [1] without
> disabling forced set affinity mask. However Thomas responded yesterday
> asking to disable it [2] on the original thread for ARM. I have
> responded on the thread and waiting for feedback from rmk and tglx. I
> would prefer to wait and align with ARM code if possible.
It is also good to call irq_set_affinity() with "force = false" to
solve the problem,
because it can give a chance to check if the passed affinity includes
only onlined cpus or not.
However, it totally relies on the implementation of irq_set_affinity(),
and it cannnot ensure that the function performs what we expect.
I think a code basically needs to be written to do exactly what it intends.
It is not bad to apply calling irq_set_affinity() with "force = false"
to the code if necessary.
But this patches also have to be applied, independently,
in order to make the code do exactly what it intends.
Thank you.
>
>> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
>> ---
>> arch/arm64/kernel/irq.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
>> index 473e5db..0c7b79e 100644
>> --- a/arch/arm64/kernel/irq.c
>> +++ b/arch/arm64/kernel/irq.c
>> @@ -87,6 +87,7 @@ static bool migrate_one_irq(struct irq_desc *desc)
>> {
>> struct irq_data *d = irq_desc_get_irq_data(desc);
>> const struct cpumask *affinity = d->affinity;
>> + struct cpumask tmp_affinity;
>> struct irq_chip *c;
>> bool ret = false;
>>
>> @@ -100,6 +101,14 @@ static bool migrate_one_irq(struct irq_desc *desc)
>> if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
>> affinity = cpu_online_mask;
>> ret = true;
>> + } else {
>> + /*
>> + * when using forced irq_set_affinity we must ensure that
>> the cpu
>> + * being offlined is not present in the affinity mask, it
>> may be
>> + * selected as the target CPU otherwise
>> + */
>> + cpumask_and(&tmp_affinity, affinity, cpu_online_mask);
>
>
> In case we decide to retain forced set affinity, you can probably squash
> this cpumask_and with the above cpumask_any_and.
>
>> + affinity = &tmp_affinity;
>> }
>>
>> c = irq_data_get_irq_chip(d);
>>
>
> Regards,
> Sudeep
>
> [1]
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/266785.html
> [2]
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/281548.html
>
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--
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max.byungchul.park
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-08-27 9:30 [PATCH 2/2] arm64: take onlined cpus into account when setting irq affinity in migrate_one_irq byungchul.park
2014-08-27 10:40 ` Sudeep Holla
2014-08-28 7:00 ` byungchul park
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