/*
* arch/ia64/kernel/domain.c
* Architecture specific sched-domains builder.
*
* Copyright (C) 2004 Jesse Barnes
* Copyright (C) 2004 Silicon Graphics, Inc.
*/
#include <linux/sched.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/cpumask.h>
#include <linux/init.h>
#include <linux/topology.h>
#include <linux/nodemask.h>
#define SD_NODES_PER_DOMAIN 6
#ifdef CONFIG_NUMA
/**
* find_next_best_node - find the next node to include in a sched_domain
* @node: node whose sched_domain we're building
* @used_nodes: nodes already in the sched_domain
*
* Find the next node to include in a given scheduling domain. Simply
* finds the closest node not already in the @used_nodes map.
*
* Should use nodemask_t.
*/
static int __devinit find_next_best_node(int node, unsigned long *used_nodes)
{
int i, n, val, min_val, best_node = 0;
min_val = INT_MAX;
for (i = 0; i < MAX_NUMNODES; i++) {
/* Start at @node */
n = (node + i) % MAX_NUMNODES;
if (!nr_cpus_node(n))
continue;
/* Skip already used nodes */
if (test_bit(n, used_nodes))
continue;
/* Simple min distance search */
val = node_distance(node, n);
if (val < min_val) {
min_val = val;
best_node = n;
}
}
set_bit(best_node, used_nodes);
return best_node;
}
/**
* sched_domain_node_span - get a cpumask for a node's sched_domain
* @node: node whose cpumask we're constructing
* @size: number of nodes to include in this span
*
* Given a node, construct a good cpumask for its sched_domain to span. It
* should be one that prevents unnecessary balancing, but also spreads tasks
* out optimally.
*/
static cpumask_t __devinit sched_domain_node_span(int node)
{
int i;
cpumask_t span, nodemask;
DECLARE_BITMAP(used_nodes, MAX_NUMNODES);
cpus_clear(span);
bitmap_zero(used_nodes, MAX_NUMNODES);
nodemask = node_to_cpumask(node);
cpus_or(span, span, nodemask);
set_bit(node, used_nodes);
for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
int next_node = find_next_best_node(node, used_nodes);
nodemask = node_to_cpumask(next_node);
cpus_or(span, span, nodemask);
}
return span;
}
#endif
/*
* At the moment, CONFIG_SCHED_SMT is never defined, but leave it in so we
* can switch it on easily if needed.
*/
#ifdef CONFIG_SCHED_SMT
static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
static struct sched_group sched_group_cpus[NR_CPUS];
static int __devinit cpu_to_cpu_group(int cpu)
{
return cpu;
}
#endif
static DEFINE_PER_CPU(struct sched_domain, phys_domains);
static struct sched_group sched_group_phys[NR_CPUS];
static int __devinit cpu_to_phys_group(int cpu)
{
#ifdef CONFIG_SCHED_SMT
return first_cpu(cpu_sibling_map[cpu]);
#else
return cpu;
#endif
}
#ifdef CONFIG_NUMA
/*
* The init_sched_build_groups can't handle what we want to do with node
* groups, so roll our own. Now each node has its own list of groups which
* gets dynamically allocated.
*/
static DEFINE_PER_CPU(struct sched_domain, node_domains);
static struct sched_group *sched_group_nodes[MAX_NUMNODES];
static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
static struct sched_group sched_group_allnodes[MAX_NUMNODES];
static int __devinit cpu_to_allnodes_group(int cpu)
{
return cpu_to_node(cpu);
}
#endif
/*
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
*/
void __devinit arch_init_sched_domains(void)
{
int i;
cpumask_t cpu_default_map;
/*
* Setup mask for cpus without special case scheduling requirements.
* For now this just excludes isolated cpus, but could be used to
* exclude other special cases in the future.
*/
cpus_complement(cpu_default_map, cpu_isolated_map);
cpus_and(cpu_default_map, cpu_default_map, cpu_online_map);
/*
* Set up domains. Isolated domains just stay on the dummy domain.
*/
for_each_cpu_mask(i, cpu_default_map) {
int group;
struct sched_domain *sd = NULL, *p;
cpumask_t nodemask = node_to_cpumask(cpu_to_node(i));
cpus_and(nodemask, nodemask, cpu_default_map);
#ifdef CONFIG_NUMA
if (num_online_cpus()
> SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) {
sd = &per_cpu(allnodes_domains, i);
*sd = SD_ALLNODES_INIT;
sd->span = cpu_default_map;
group = cpu_to_allnodes_group(i);
sd->groups = &sched_group_allnodes[group];
p = sd;
} else
p = NULL;
sd = &per_cpu(node_domains, i);
*sd = SD_NODE_INIT;
sd->span = sched_domain_node_span(cpu_to_node(i));
sd->parent = p;
cpus_and(sd->span, sd->span, cpu_default_map);
#endif
p = sd;
sd = &per_cpu(phys_domains, i);
group = cpu_to_phys_group(i);
*sd = SD_CPU_INIT;
sd->span = nodemask;
sd->parent = p;
sd->groups = &sched_group_phys[group];
#ifdef CONFIG_SCHED_SMT
p = sd;
sd = &per_cpu(cpu_domains, i);
group = cpu_to_cpu_group(i);
*sd = SD_SIBLING_INIT;
sd->span = cpu_sibling_map[i];
cpus_and(sd->span, sd->span, cpu_default_map);
sd->parent = p;
sd->groups = &sched_group_cpus[group];
#endif
}
#ifdef CONFIG_SCHED_SMT
/* Set up CPU (sibling) groups */
for_each_cpu_mask(i, cpu_default_map) {
cpumask_t this_sibling_map = cpu_sibling_map[i];
cpus_and(this_sibling_map, this_sibling_map, cpu_default_map);
if (i != first_cpu(this_sibling_map))
continue;
init_sched_build_groups(sched_group_cpus, this_sibling_map,
&cpu_to_cpu_group);
}
#endif
/* Set up physical groups */
for (i = 0; i < MAX_NUMNODES; i++) {
cpumask_t nodemask = node_to_cpumask(i);
cpus_and(nodemask, nodemask, cpu_default_map);
if (cpus_empty(nodemask))
continue;
init_sched_build_groups(sched_group_phys, nodemask,
&cpu_to_phys_group);
}
#ifdef CONFIG_NUMA
init_sched_build_groups(sched_group_allnodes, cpu_default_map,
&cpu_to_allnodes_group);
for (i = 0; i < MAX_NUMNODES; i++) {
/* Set up node groups */
struct sched_group *sg, *prev;
cpumask_t nodemask = node_to_cpumask(i);
cpumask_t domainspan;
cpumask_t covered = CPU_MASK_NONE;
int j;
cpus_and(nodemask, nodemask, cpu_default_map);
if (cpus_empty(nodemask))
continue;
domainspan = sched_domain_node_span(i);
cpus_and(domainspan, domainspan, cpu_default_map);
sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL);
sched_group_nodes[i] = sg;
for_each_cpu_mask(j, nodemask) {
struct sched_domain *sd;
sd = &per_cpu(node_domains, j);
sd->groups = sg;
if (sd->groups == NULL) {
/* Turn off balancing if we have no groups */
sd->flags = 0;
}
}
if (!sg) {
printk(KERN_WARNING
"Can not alloc domain group for node %d\n", i);
continue;
}
sg->cpu_power = 0;
sg->cpumask = nodemask;
cpus_or(covered, covered, nodemask);
prev = sg;
for (j = 0; j < MAX_NUMNODES; j++) {
cpumask_t tmp, notcovered;
int n = (i + j) % MAX_NUMNODES;
cpus_complement(notcovered, covered);
cpus_and(tmp, notcovered, cpu_default_map);
cpus_and(tmp, tmp, domainspan);
if (cpus_empty(tmp))
break;
nodemask = node_to_cpumask(n);
cpus_and(tmp, tmp, nodemask);
if (cpus_empty(tmp))
continue;
sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL);
if (!sg) {
printk(KERN_WARNING
"Can not alloc domain group for node %d\n", j);
break;
}
sg->cpu_power = 0;
sg->cpumask = tmp;
cpus_or(covered, covered, tmp);
prev->next = sg;
prev = sg;
}
prev->next = sched_group_nodes[i];
}
#endif
/* Calculate CPU power for physical packages and nodes */
for_each_cpu_mask(i, cpu_default_map) {
int power;
struct sched_domain *sd;
#ifdef CONFIG_SCHED_SMT
sd = &per_cpu(cpu_domains, i);
power = SCHED_LOAD_SCALE;
sd->groups->cpu_power = power;
#endif
sd = &per_cpu(phys_domains, i);
power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
(cpus_weight(sd->groups->cpumask)-1) / 10;
sd->groups->cpu_power = power;
#ifdef CONFIG_NUMA
sd = &per_cpu(allnodes_domains, i);
if (sd->groups) {
power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
(cpus_weight(sd->groups->cpumask)-1) / 10;
sd->groups->cpu_power = power;
}
#endif
}
#ifdef CONFIG_NUMA
for (i = 0; i < MAX_NUMNODES; i++) {
struct sched_group *sg = sched_group_nodes[i];
int j;
if (sg == NULL)
continue;
next_sg:
for_each_cpu_mask(j, sg->cpumask) {
struct sched_domain *sd;
int power;
sd = &per_cpu(phys_domains, j);
if (j != first_cpu(sd->groups->cpumask)) {
/*
* Only add "power" once for each
* physical package.
*/
continue;
}
power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
(cpus_weight(sd->groups->cpumask)-1) / 10;
sg->cpu_power += power;
}
sg = sg->next;
if (sg != sched_group_nodes[i])
goto next_sg;
}
#endif
/* Attach the domains */
for_each_online_cpu(i) {
struct sched_domain *sd;
#ifdef CONFIG_SCHED_SMT
sd = &per_cpu(cpu_domains, i);
#else
sd = &per_cpu(phys_domains, i);
#endif
cpu_attach_domain(sd, i);
}
}
void __devinit arch_destroy_sched_domains(void)
{
#ifdef CONFIG_NUMA
int i;
for (i = 0; i < MAX_NUMNODES; i++) {
struct sched_group *oldsg, *sg = sched_group_nodes[i];
if (sg == NULL)
continue;
sg = sg->next;
next_sg:
oldsg = sg;
sg = sg->next;
kfree(oldsg);
if (oldsg != sched_group_nodes[i])
goto next_sg;
sched_group_nodes[i] = NULL;
}
#endif
}
