Messages in this thread | | | Date | Wed, 19 Apr 2017 10:11:16 +0200 | From | Peter Zijlstra <> | Subject | Re: [patch V2 08/10] timer: Implement the hierarchical pull model |
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On Tue, Apr 18, 2017 at 01:11:10PM +0200, Thomas Gleixner wrote: > +static struct tmigr_group *tmigr_get_group(unsigned int node, unsigned int lvl) > +{ > + struct tmigr_group *group; > + > + /* Try to attach to an exisiting group first */ > + list_for_each_entry(group, &tmigr_level_list[lvl], list) { > + /* > + * If @lvl is below the cross numa node level, check > + * whether this group belongs to the same numa node. > + */ > + if (lvl < tmigr_crossnode_level && group->numa_node != node) > + continue; > + /* If the group has capacity, use it */ > + if (group->num_childs < tmigr_childs_per_group) { > + group->num_childs++; > + return group; > + }
This would result in SMT siblings not sharing groups on regular Intel systems, right? Since they get enumerated last.
> + } > + /* Allocate and set up a new group */ > + group = kzalloc_node(sizeof(*group), GFP_KERNEL, node); > + if (!group) > + return ERR_PTR(-ENOMEM); > + > + if (!zalloc_cpumask_var_node(&group->cpus, GFP_KERNEL, node)) { > + kfree(group); > + return ERR_PTR(-ENOMEM); > + }
So if you place that cpumask last, you can do:
group = kzalloc_node(sizeof(*group) + cpumask_size(), GFP_KERNEL, node);
> + tmigr_init_group(group, lvl, node); > + /* Setup successful. Add it to the hierarchy */ > + list_add(&group->list, &tmigr_level_list[lvl]); > + return group; > +}
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