2021-12-17 11:00:49

by Rei Yamamoto

Subject: [PATCH v2] irq: consider cpus on nodes are unbalanced

If cpus on a node are offline at boot time, there are
difference in the number of nodes between when building affinity
masks for present cpus and when building affinity masks for possible
cpus. This patch fixes a problem caused by the difference of the
number of nodes:

- The routine of "numvecs <= nodes" condition can overwrite bits of
masks for present cpus in building masks for possible cpus. Fix this
problem by making CPU bits, which is not target, not changing.

Signed-off-by: Rei Yamamoto <[email protected]>
---
kernel/irq/affinity.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index f7ff8919dc9b..d2d01565d2ec 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -269,8 +269,9 @@ static int __irq_build_affinity_masks(unsigned int startvec,
*/
if (numvecs <= nodes) {
for_each_node_mask(n, nodemsk) {
+ cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
cpumask_or(&masks[curvec].mask, &masks[curvec].mask,
- node_to_cpumask[n]);
+ nmsk);
if (++curvec == last_affv)
curvec = firstvec;
}
--
2.27.0

2021-12-17 12:05:01

by Ming Lei

Subject: Re: [PATCH v2] irq: consider cpus on nodes are unbalanced

On Fri, Dec 17, 2021 at 07:44:07PM +0900, Rei Yamamoto wrote:
> If cpus on a node are offline at boot time, there are
> difference in the number of nodes between when building affinity
> masks for present cpus and when building affinity masks for possible
> cpus. This patch fixes a problem caused by the difference of the
> number of nodes:
>
> - The routine of "numvecs <= nodes" condition can overwrite bits of
> masks for present cpus in building masks for possible cpus. Fix this
> problem by making CPU bits, which is not target, not changing.
>
> Signed-off-by: Rei Yamamoto <[email protected]>
> ---
> kernel/irq/affinity.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index f7ff8919dc9b..d2d01565d2ec 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -269,8 +269,9 @@ static int __irq_build_affinity_masks(unsigned int startvec,
> */
> if (numvecs <= nodes) {
> for_each_node_mask(n, nodemsk) {
> + cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
> cpumask_or(&masks[curvec].mask, &masks[curvec].mask,
> - node_to_cpumask[n]);
> + nmsk);
> if (++curvec == last_affv)
> curvec = firstvec;

Looks fine,

Reviewed-by: Ming Lei <[email protected]>

--
Ming

2022-01-14 02:22:19

by Rei Yamamoto

Subject: Re: [PATCH v2] irq: consider cpus on nodes are unbalanced

On Fri, Dec 17, 2021 at 20:04, Ming Lei wrote:
> On Fri, Dec 17, 2021 at 07:44:07PM +0900, Rei Yamamoto wrote:
>> If cpus on a node are offline at boot time, there are
>> difference in the number of nodes between when building affinity
>> masks for present cpus and when building affinity masks for possible
>> cpus. This patch fixes a problem caused by the difference of the
>> number of nodes:
>>
>> - The routine of "numvecs <= nodes" condition can overwrite bits of
>> masks for present cpus in building masks for possible cpus. Fix this
>> problem by making CPU bits, which is not target, not changing.
>>
>> Signed-off-by: Rei Yamamoto <[email protected]>
>> ---
>> kernel/irq/affinity.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
>> index f7ff8919dc9b..d2d01565d2ec 100644
>> --- a/kernel/irq/affinity.c
>> +++ b/kernel/irq/affinity.c
>> @@ -269,8 +269,9 @@ static int __irq_build_affinity_masks(unsigned int startvec,
>> */
>> if (numvecs <= nodes) {
>> for_each_node_mask(n, nodemsk) {
>> + cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
>> cpumask_or(&masks[curvec].mask, &masks[curvec].mask,
>> - node_to_cpumask[n]);
>> + nmsk);
>> if (++curvec == last_affv)
>> curvec = firstvec;
>
> Looks fine,
>
> Reviewed-by: Ming Lei <[email protected]>

Thank you for your review.
Does anyone else have a comment?

Thanks,
Rei