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Message-ID: <YgSQKvv7rL6MFPRr@T590>
Date: Thu, 10 Feb 2022 12:10:18 +0800
From: Ming Lei <ming.lei@...hat.com>
To: Rei Yamamoto <yamamoto.rei@...fujitsu.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] irq: consider cpus on nodes are unbalanced
On Thu, Feb 10, 2022 at 12:10:53PM +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 <yamamoto.rei@...fujitsu.com>
> Reviewed-by: Ming Lei <ming.lei@...hat.com>
> ---
> 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
>
--
Ming
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