2005-09-02 20:11:13

by John Hawkes

Subject: [PATCH 2/3] 2.6.13-mm1: cpuset + build_sched_domains() fix

Ingo, Dino, and Andrew,

Here is the "cpuset + build_sched_domains() mangles structures" set of
patches against 2.6.13-mm1.

Patch #2: Fix the "dynamic sched domains" bug:
* For a NUMA system with multiple CPUs per node, declaring a
cpu-exclusive cpuset that includes only some, but not all, of the
CPUs in a node will mangle the sched domain structures.

Signed-off-by: John Hawkes <[email protected]>

Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c 2005-09-02 10:46:27.000000000 -0700
+++ linux/kernel/sched.c 2005-09-02 11:17:46.000000000 -0700
@@ -5305,10 +5305,10 @@
* gets dynamically allocated.
*/
static DEFINE_PER_CPU(struct sched_domain, node_domains);
-static struct sched_group *sched_group_nodes[MAX_NUMNODES];
+static struct sched_group **sched_group_nodes_bycpu[NR_CPUS];

static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
-static struct sched_group sched_group_allnodes[MAX_NUMNODES];
+static struct sched_group *sched_group_allnodes_bycpu[NR_CPUS];

static int cpu_to_allnodes_group(int cpu)
{
@@ -5323,6 +5323,21 @@
void build_sched_domains(const cpumask_t *cpu_map)
{
int i;
+#ifdef CONFIG_NUMA
+ struct sched_group **sched_group_nodes = NULL;
+ struct sched_group *sched_group_allnodes = NULL;
+
+ /*
+ * Allocate the per-node list of sched groups
+ */
+ sched_group_nodes = kmalloc(sizeof(struct sched_group*)*MAX_NUMNODES,
+ GFP_ATOMIC);
+ if (!sched_group_nodes) {
+ printk(KERN_WARNING "Can not alloc sched group node list\n");
+ return;
+ }
+ sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
+#endif

/*
* Set up domains for cpus specified by the cpu_map.
@@ -5335,8 +5350,21 @@
cpus_and(nodemask, nodemask, *cpu_map);

#ifdef CONFIG_NUMA
- if (num_online_cpus()
+ if (cpus_weight(*cpu_map)
> SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) {
+ if (!sched_group_allnodes) {
+ sched_group_allnodes
+ = kmalloc(sizeof(struct sched_group)
+ * MAX_NUMNODES,
+ GFP_KERNEL);
+ if (!sched_group_allnodes) {
+ printk(KERN_WARNING
+ "Can not alloc allnodes sched group\n");
+ break;
+ }
+ sched_group_allnodes_bycpu[i]
+ = sched_group_allnodes;
+ }
sd = &per_cpu(allnodes_domains, i);
*sd = SD_ALLNODES_INIT;
sd->span = *cpu_map;
@@ -5400,8 +5428,9 @@

#ifdef CONFIG_NUMA
/* Set up node groups */
- init_sched_build_groups(sched_group_allnodes, *cpu_map,
- &cpu_to_allnodes_group);
+ if (sched_group_allnodes)
+ init_sched_build_groups(sched_group_allnodes, *cpu_map,
+ &cpu_to_allnodes_group);

for (i = 0; i < MAX_NUMNODES; i++) {
/* Set up node groups */
@@ -5412,8 +5441,10 @@
int j;

cpus_and(nodemask, nodemask, *cpu_map);
- if (cpus_empty(nodemask))
+ if (cpus_empty(nodemask)) {
+ sched_group_nodes[i] = NULL;
continue;
+ }

domainspan = sched_domain_node_span(i);
cpus_and(domainspan, domainspan, *cpu_map);
@@ -5558,24 +5589,42 @@
{
#ifdef CONFIG_NUMA
int i;
- for (i = 0; i < MAX_NUMNODES; i++) {
- cpumask_t nodemask = node_to_cpumask(i);
- struct sched_group *oldsg, *sg = sched_group_nodes[i];
+ int cpu;

- cpus_and(nodemask, nodemask, *cpu_map);
- if (cpus_empty(nodemask))
- continue;
+ for_each_cpu_mask(cpu, *cpu_map) {
+ struct sched_group *sched_group_allnodes
+ = sched_group_allnodes_bycpu[cpu];
+ struct sched_group **sched_group_nodes
+ = sched_group_nodes_bycpu[cpu];
+
+ if (sched_group_allnodes) {
+ kfree(sched_group_allnodes);
+ sched_group_allnodes_bycpu[cpu] = NULL;
+ }

- if (sg == NULL)
+ if (!sched_group_nodes)
continue;
- sg = sg->next;
+
+ for (i = 0; i < MAX_NUMNODES; i++) {
+ cpumask_t nodemask = node_to_cpumask(i);
+ struct sched_group *oldsg, *sg = sched_group_nodes[i];
+
+ cpus_and(nodemask, nodemask, *cpu_map);
+ if (cpus_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;
- sched_group_nodes[i] = NULL;
+ 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;
}
#endif
}