On Sat, 22 Oct 2016, Fenghua Yu wrote:
> +void rdt_cbm_update(void *arg)
> +{
> + struct msr_param *m = (struct msr_param *)arg;
> + struct rdt_resource *r = m->res;
> + int i, cpu = smp_processor_id();
> + struct rdt_domain *d;
> +
> + list_for_each_entry(d, &r->domains, list) {
> +static struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
> + struct list_head **pos)
> +{
> + struct rdt_domain *d;
> + struct list_head *l;
> +
> + if (id < 0)
> + return ERR_PTR(id);
> +
> + list_for_each(l, &r->domains) {
> + d = list_entry(l, struct rdt_domain, list);
So above you converted to list_for_each_entry(). Is there a sensible
reason, aside of being sloppy, why is this still using list_for_each()?
> + /* When id is found, return its domain. */
> + if (id == d->id)
> + return d;
> + /* Stop searching when finding id's position in sorted list. */
What is the reason that this needs to be in a sorted list?
I haven't found one so far. And if there is none, then this can use a hlist.
> + if (id < d->id)
> + break;
> + }
> + /*
> + * No id is found in resource domains. Record the position
> + * that the new domain will be added. The posistion is not used
> + * when removing a domain.
This comment makes no sense. If you want to document that a caller does not
require the @pos argument, then you really should make it optional and do
if (pos)
*pos = l;
But before doing that blindly, you want to explain why sorting is required
at all.
> + */
> + *pos = l;
> +
> + return NULL;
> +}
> +
> +static void domain_add_cpu(int cpu, struct rdt_resource *r)
> +{
> + int i, id = get_cache_id(cpu, r->cache_level);
> + struct list_head *add_pos = NULL;
> + struct rdt_domain *d;
> +
> + d = rdt_find_domain(r, id, &add_pos);
> + if (IS_ERR(d)) {
> + pr_warn("Could't find cache id for cpu %d\n", cpu);
> + return;
> + }
> +
> + if (d) {
> + cpumask_set_cpu(cpu, &d->cpu_mask);
> + return;
> + }
> +
> + if (!add_pos) {
> + pr_warn("Couldn't add cpu %d in %s domain\n", cpu, r->name);
Errm, how can add_pos ever be NULL if you get here? Not at all AFAICT.
> + return;
> + }
> +
> + d = kzalloc_node(sizeof(*d), GFP_KERNEL, cpu_to_node(cpu));
> + if (!d)
> + return;
> +
> + d->id = id;
Please move this after the allocation. This random code ordering just makes
reading hard as one expects that d->id is a prerequisite for the
allocation.
> + d->cbm = kmalloc_array(r->num_closid, sizeof(*d->cbm), GFP_KERNEL);
> + if (!d->cbm) {
> + pr_warn("Failed to alloc CBM array for cpu %d\n", cpu);
> + kfree(d);
> + return;
> + }
New line please. Visually seperating logical code blocks enhances
readability.
> + for (i = 0; i < r->num_closid; i++) {
Thanks,
tglx
