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SubjectRe: [PATCH] Revert "genirq/affinity: assign vectors to all possible CPUs"
On Mon, Oct 01, 2018 at 02:33:07PM +0200, Paul Menzel wrote:
> Date: Wed, 29 Aug 2018 17:28:45 +0200
>
> This reverts commit ef86f3a72adb8a7931f67335560740a7ad696d1d.
>
> See the discussion in the thread *aacraid: Regression in 4.14.56
> with *genirq/affinity: assign vectors to all possible CPUs** on
> the linux-scsi list.
>
> Reverting the commit, the aacraid driver loads correctly, and the
> drives are visible. So revert the commit to adhere to Linux’ no
> regression policy.
>
> Strangely, the issue is not reproducible with Linux 4.18.x, but
> Ming Lei wrote, that this might only be by chance.
>
> Link: https://www.spinics.net/lists/linux-scsi/msg122732.html
> Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
>
> ---
> kernel/irq/affinity.c | 30 +++++++++++++++---------------
> 1 file changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index a37a3b4b6342..e12d35108225 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -39,7 +39,7 @@ static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
> }
> }
>
> -static cpumask_var_t *alloc_node_to_possible_cpumask(void)
> +static cpumask_var_t *alloc_node_to_present_cpumask(void)
> {
> cpumask_var_t *masks;
> int node;
> @@ -62,7 +62,7 @@ static cpumask_var_t *alloc_node_to_possible_cpumask(void)
> return NULL;
> }
>
> -static void free_node_to_possible_cpumask(cpumask_var_t *masks)
> +static void free_node_to_present_cpumask(cpumask_var_t *masks)
> {
> int node;
>
> @@ -71,22 +71,22 @@ static void free_node_to_possible_cpumask(cpumask_var_t *masks)
> kfree(masks);
> }
>
> -static void build_node_to_possible_cpumask(cpumask_var_t *masks)
> +static void build_node_to_present_cpumask(cpumask_var_t *masks)
> {
> int cpu;
>
> - for_each_possible_cpu(cpu)
> + for_each_present_cpu(cpu)
> cpumask_set_cpu(cpu, masks[cpu_to_node(cpu)]);
> }
>
> -static int get_nodes_in_cpumask(cpumask_var_t *node_to_possible_cpumask,
> +static int get_nodes_in_cpumask(cpumask_var_t *node_to_present_cpumask,
> const struct cpumask *mask, nodemask_t *nodemsk)
> {
> int n, nodes = 0;
>
> /* Calculate the number of nodes in the supplied affinity mask */
> for_each_node(n) {
> - if (cpumask_intersects(mask, node_to_possible_cpumask[n])) {
> + if (cpumask_intersects(mask, node_to_present_cpumask[n])) {
> node_set(n, *nodemsk);
> nodes++;
> }
> @@ -109,7 +109,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> int last_affv = affv + affd->pre_vectors;
> nodemask_t nodemsk = NODE_MASK_NONE;
> struct cpumask *masks;
> - cpumask_var_t nmsk, *node_to_possible_cpumask;
> + cpumask_var_t nmsk, *node_to_present_cpumask;
>
> /*
> * If there aren't any vectors left after applying the pre/post
> @@ -125,8 +125,8 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> if (!masks)
> goto out;
>
> - node_to_possible_cpumask = alloc_node_to_possible_cpumask();
> - if (!node_to_possible_cpumask)
> + node_to_present_cpumask = alloc_node_to_present_cpumask();
> + if (!node_to_present_cpumask)
> goto out;
>
> /* Fill out vectors at the beginning that don't need affinity */
> @@ -135,8 +135,8 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
>
> /* Stabilize the cpumasks */
> get_online_cpus();
> - build_node_to_possible_cpumask(node_to_possible_cpumask);
> - nodes = get_nodes_in_cpumask(node_to_possible_cpumask, cpu_possible_mask,
> + build_node_to_present_cpumask(node_to_present_cpumask);
> + nodes = get_nodes_in_cpumask(node_to_present_cpumask, cpu_present_mask,
> &nodemsk);
>
> /*
> @@ -146,7 +146,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> if (affv <= nodes) {
> for_each_node_mask(n, nodemsk) {
> cpumask_copy(masks + curvec,
> - node_to_possible_cpumask[n]);
> + node_to_present_cpumask[n]);
> if (++curvec == last_affv)
> break;
> }
> @@ -160,7 +160,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes;
>
> /* Get the cpus on this node which are in the mask */
> - cpumask_and(nmsk, cpu_possible_mask, node_to_possible_cpumask[n]);
> + cpumask_and(nmsk, cpu_present_mask, node_to_present_cpumask[n]);
>
> /* Calculate the number of cpus per vector */
> ncpus = cpumask_weight(nmsk);
> @@ -192,7 +192,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> /* Fill out vectors at the end that don't need affinity */
> for (; curvec < nvecs; curvec++)
> cpumask_copy(masks + curvec, irq_default_affinity);
> - free_node_to_possible_cpumask(node_to_possible_cpumask);
> + free_node_to_present_cpumask(node_to_present_cpumask);
> out:
> free_cpumask_var(nmsk);
> return masks;
> @@ -214,7 +214,7 @@ int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity
> return 0;
>
> get_online_cpus();
> - ret = min_t(int, cpumask_weight(cpu_possible_mask), vecs) + resv;
> + ret = min_t(int, cpumask_weight(cpu_present_mask), vecs) + resv;
> put_online_cpus();
> return ret;
> }
> --
> 2.17.1
>

Hello Paul,

I have explained that this is one aacraid issue in the following link:

https://marc.info/?l=linux-kernel&m=153413115909580&w=2

So this issue should have been fixed in the driver instead of genirq
core code, otherwise regression on other drivers can be caused too.

So I suggest you to ask aacraid guys to take a look at this issue.

Thanks,
Ming

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