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sched: Change NODE sched_domain group creation
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The NODE sched_domain is 'special' in that it allocates sched_groups
per CPU, instead of sharing the sched_groups between all CPUs.

While this might have some benefits on large NUMA and avoid remote
memory accesses when iterating the sched_groups, this does break
current code that assumes sched_groups are shared between all
sched_domains (since the dynamic cpu_power patches).

So refactor the NODE groups to behave like all other groups.

(The ALLNODES domain again shared its groups across the CPUs for some
reason).

If someone does measure a performance decrease due to this change we
need to revisit this and come up with another way to have both dynamic
cpu_power and NUMA work nice together.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122941.978111700@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Peter Zijlstra authored and Ingo Molnar committed Apr 11, 2011
1 parent a06dadb commit cd4ea6a
Showing 1 changed file with 32 additions and 197 deletions.
229 changes: 32 additions & 197 deletions kernel/sched.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6861,29 +6861,18 @@ struct static_sched_domain {
struct s_data {
#ifdef CONFIG_NUMA
int sd_allnodes;
cpumask_var_t domainspan;
cpumask_var_t covered;
cpumask_var_t notcovered;
#endif
cpumask_var_t nodemask;
cpumask_var_t send_covered;
cpumask_var_t tmpmask;
struct sched_group **sched_group_nodes;
struct root_domain *rd;
};

enum s_alloc {
sa_sched_groups = 0,
sa_rootdomain,
sa_tmpmask,
sa_send_covered,
sa_nodemask,
sa_sched_group_nodes,
#ifdef CONFIG_NUMA
sa_notcovered,
sa_covered,
sa_domainspan,
#endif
sa_none,
};

Expand Down Expand Up @@ -6979,18 +6968,10 @@ cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
}

#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 static_sched_domain, node_domains);
static struct sched_group ***sched_group_nodes_bycpu;

static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
static DEFINE_PER_CPU(struct static_sched_group, sched_group_node);

static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
static int cpu_to_node_group(int cpu, const struct cpumask *cpu_map,
struct sched_group **sg,
struct cpumask *nodemask)
{
Expand All @@ -7000,142 +6981,27 @@ static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
group = cpumask_first(nodemask);

if (sg)
*sg = &per_cpu(sched_group_allnodes, group).sg;
*sg = &per_cpu(sched_group_node, group).sg;
return group;
}

static void init_numa_sched_groups_power(struct sched_group *group_head)
{
struct sched_group *sg = group_head;
int j;

if (!sg)
return;
do {
for_each_cpu(j, sched_group_cpus(sg)) {
struct sched_domain *sd;

sd = &per_cpu(phys_domains, j).sd;
if (j != group_first_cpu(sd->groups)) {
/*
* Only add "power" once for each
* physical package.
*/
continue;
}

sg->cpu_power += sd->groups->cpu_power;
}
sg = sg->next;
} while (sg != group_head);
}
static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);

static int build_numa_sched_groups(struct s_data *d,
const struct cpumask *cpu_map, int num)
static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
struct sched_group **sg,
struct cpumask *nodemask)
{
struct sched_domain *sd;
struct sched_group *sg, *prev;
int n, j;

cpumask_clear(d->covered);
cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map);
if (cpumask_empty(d->nodemask)) {
d->sched_group_nodes[num] = NULL;
goto out;
}

sched_domain_node_span(num, d->domainspan);
cpumask_and(d->domainspan, d->domainspan, cpu_map);

sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
GFP_KERNEL, num);
if (!sg) {
printk(KERN_WARNING "Can not alloc domain group for node %d\n",
num);
return -ENOMEM;
}
d->sched_group_nodes[num] = sg;

for_each_cpu(j, d->nodemask) {
sd = &per_cpu(node_domains, j).sd;
sd->groups = sg;
}
int group;

sg->cpu_power = 0;
cpumask_copy(sched_group_cpus(sg), d->nodemask);
sg->next = sg;
cpumask_or(d->covered, d->covered, d->nodemask);
cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
group = cpumask_first(nodemask);

prev = sg;
for (j = 0; j < nr_node_ids; j++) {
n = (num + j) % nr_node_ids;
cpumask_complement(d->notcovered, d->covered);
cpumask_and(d->tmpmask, d->notcovered, cpu_map);
cpumask_and(d->tmpmask, d->tmpmask, d->domainspan);
if (cpumask_empty(d->tmpmask))
break;
cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n));
if (cpumask_empty(d->tmpmask))
continue;
sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
GFP_KERNEL, num);
if (!sg) {
printk(KERN_WARNING
"Can not alloc domain group for node %d\n", j);
return -ENOMEM;
}
sg->cpu_power = 0;
cpumask_copy(sched_group_cpus(sg), d->tmpmask);
sg->next = prev->next;
cpumask_or(d->covered, d->covered, d->tmpmask);
prev->next = sg;
prev = sg;
}
out:
return 0;
if (sg)
*sg = &per_cpu(sched_group_allnodes, group).sg;
return group;
}
#endif /* CONFIG_NUMA */

#ifdef CONFIG_NUMA
/* Free memory allocated for various sched_group structures */
static void free_sched_groups(const struct cpumask *cpu_map,
struct cpumask *nodemask)
{
int cpu, i;

for_each_cpu(cpu, cpu_map) {
struct sched_group **sched_group_nodes
= sched_group_nodes_bycpu[cpu];

if (!sched_group_nodes)
continue;

for (i = 0; i < nr_node_ids; i++) {
struct sched_group *oldsg, *sg = sched_group_nodes[i];

cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
if (cpumask_empty(nodemask))
continue;

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;
}
kfree(sched_group_nodes);
sched_group_nodes_bycpu[cpu] = NULL;
}
}
#else /* !CONFIG_NUMA */
static void free_sched_groups(const struct cpumask *cpu_map,
struct cpumask *nodemask)
{
}
#endif /* CONFIG_NUMA */

/*
Expand Down Expand Up @@ -7236,9 +7102,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
const struct cpumask *cpu_map)
{
switch (what) {
case sa_sched_groups:
free_sched_groups(cpu_map, d->tmpmask); /* fall through */
d->sched_group_nodes = NULL;
case sa_rootdomain:
free_rootdomain(d->rd); /* fall through */
case sa_tmpmask:
Expand All @@ -7247,16 +7110,6 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
free_cpumask_var(d->send_covered); /* fall through */
case sa_nodemask:
free_cpumask_var(d->nodemask); /* fall through */
case sa_sched_group_nodes:
#ifdef CONFIG_NUMA
kfree(d->sched_group_nodes); /* fall through */
case sa_notcovered:
free_cpumask_var(d->notcovered); /* fall through */
case sa_covered:
free_cpumask_var(d->covered); /* fall through */
case sa_domainspan:
free_cpumask_var(d->domainspan); /* fall through */
#endif
case sa_none:
break;
}
Expand All @@ -7265,24 +7118,8 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
const struct cpumask *cpu_map)
{
#ifdef CONFIG_NUMA
if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL))
return sa_none;
if (!alloc_cpumask_var(&d->covered, GFP_KERNEL))
return sa_domainspan;
if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL))
return sa_covered;
/* Allocate the per-node list of sched groups */
d->sched_group_nodes = kcalloc(nr_node_ids,
sizeof(struct sched_group *), GFP_KERNEL);
if (!d->sched_group_nodes) {
printk(KERN_WARNING "Can not alloc sched group node list\n");
return sa_notcovered;
}
sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes;
#endif
if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL))
return sa_sched_group_nodes;
return sa_none;
if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
return sa_nodemask;
if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL))
Expand Down Expand Up @@ -7322,6 +7159,7 @@ static struct sched_domain *__build_numa_sched_domains(struct s_data *d,
if (parent)
parent->child = sd;
cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map);
cpu_to_node_group(i, cpu_map, &sd->groups, d->tmpmask);
#endif
return sd;
}
Expand Down Expand Up @@ -7434,6 +7272,13 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l,
d->send_covered, d->tmpmask);
break;
#ifdef CONFIG_NUMA
case SD_LV_NODE:
sd = &per_cpu(node_domains, cpu).sd;
if (cpu == cpumask_first(sched_domain_span(sd)))
init_sched_build_groups(sched_domain_span(sd), cpu_map,
&cpu_to_node_group,
d->send_covered, d->tmpmask);

case SD_LV_ALLNODES:
init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group,
d->send_covered, d->tmpmask);
Expand Down Expand Up @@ -7462,7 +7307,6 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
if (alloc_state != sa_rootdomain)
goto error;
alloc_state = sa_sched_groups;

/*
* Set up domains for cpus specified by the cpu_map.
Expand All @@ -7486,16 +7330,13 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
build_sched_groups(&d, SD_LV_BOOK, cpu_map, i);
build_sched_groups(&d, SD_LV_MC, cpu_map, i);
build_sched_groups(&d, SD_LV_CPU, cpu_map, i);
build_sched_groups(&d, SD_LV_NODE, cpu_map, i);
}

#ifdef CONFIG_NUMA
/* Set up node groups */
if (d.sd_allnodes)
build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0);

for (i = 0; i < nr_node_ids; i++)
if (build_numa_sched_groups(&d, cpu_map, i))
goto error;
#endif

/* Calculate CPU power for physical packages and nodes */
Expand Down Expand Up @@ -7524,15 +7365,16 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
}

#ifdef CONFIG_NUMA
for (i = 0; i < nr_node_ids; i++)
init_numa_sched_groups_power(d.sched_group_nodes[i]);
for_each_cpu(i, cpu_map) {
sd = &per_cpu(node_domains, i).sd;
init_sched_groups_power(i, sd);
}

if (d.sd_allnodes) {
struct sched_group *sg;

cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
d.tmpmask);
init_numa_sched_groups_power(sg);
for_each_cpu(i, cpu_map) {
sd = &per_cpu(allnodes_domains, i).sd;
init_sched_groups_power(i, sd);
}
}
#endif

Expand All @@ -7550,7 +7392,6 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
cpu_attach_domain(sd, d.rd, i);
}

d.sched_group_nodes = NULL; /* don't free this we still need it */
__free_domain_allocs(&d, sa_tmpmask, cpu_map);
return 0;

Expand Down Expand Up @@ -7636,7 +7477,6 @@ static int init_sched_domains(const struct cpumask *cpu_map)
static void destroy_sched_domains(const struct cpumask *cpu_map,
struct cpumask *tmpmask)
{
free_sched_groups(cpu_map, tmpmask);
}

/*
Expand Down Expand Up @@ -7913,11 +7753,6 @@ void __init sched_init_smp(void)
alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
alloc_cpumask_var(&fallback_doms, GFP_KERNEL);

#if defined(CONFIG_NUMA)
sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
GFP_KERNEL);
BUG_ON(sched_group_nodes_bycpu == NULL);
#endif
get_online_cpus();
mutex_lock(&sched_domains_mutex);
init_sched_domains(cpu_active_mask);
Expand Down

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