As explained here:
http://marc.theaimsgroup.com/?l=linux-kernel&m=114327539012323&w=2
there is a problem with sharing sched_group structures between two
different sched_domains. This patch overcomes the problem by allocating
separate sched_group structures for different sched_domains.
The patch has been tested and found to avoid the kernel lockup problem described
in above URL.
Signed-off-by: Srivatsa Vaddagiri <[email protected]>
diff -puN kernel/sched.c~sd_dynschedgroup kernel/sched.c
--- linux-2.6.16-mm2/kernel/sched.c~sd_dynschedgroup 2006-04-01 23:40:56.000000000 +0530
+++ linux-2.6.16-mm2-root/kernel/sched.c 2006-04-01 23:40:56.000000000 +0530
@@ -5988,7 +5988,7 @@ static int cpu_to_cpu_group(int cpu)
#ifdef CONFIG_SCHED_MC
static DEFINE_PER_CPU(struct sched_domain, core_domains);
-static struct sched_group sched_group_core[NR_CPUS];
+static struct sched_group *sched_group_core_bycpu[NR_CPUS];
#endif
#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
@@ -6004,7 +6004,7 @@ static int cpu_to_core_group(int cpu)
#endif
static DEFINE_PER_CPU(struct sched_domain, phys_domains);
-static struct sched_group sched_group_phys[NR_CPUS];
+static struct sched_group *sched_group_phys_bycpu[NR_CPUS];
static int cpu_to_phys_group(int cpu)
{
#if defined(CONFIG_SCHED_MC)
@@ -6064,9 +6064,9 @@ next_sg:
/* Free memory allocated for various sched_group structures */
static void free_sched_groups(const cpumask_t *cpu_map)
{
+ int cpu;
#ifdef CONFIG_NUMA
int i;
- int cpu;
for_each_cpu_mask(cpu, *cpu_map) {
struct sched_group *sched_group_allnodes
@@ -6104,6 +6104,18 @@ next_sg:
sched_group_nodes_bycpu[cpu] = NULL;
}
#endif
+ for_each_cpu_mask(cpu, *cpu_map) {
+ if (sched_group_phys_bycpu[cpu]) {
+ kfree(sched_group_phys_bycpu[cpu]);
+ sched_group_phys_bycpu[cpu] = NULL;
+ }
+#ifdef CONFIG_SCHED_MC
+ if (sched_group_core_bycpu[cpu]) {
+ kfree(sched_group_core_bycpu[cpu]);
+ sched_group_core_bycpu[cpu] = NULL;
+ }
+#endif
+ }
}
/*
@@ -6113,6 +6125,10 @@ next_sg:
static int build_sched_domains(const cpumask_t *cpu_map)
{
int i;
+ struct sched_group *sched_group_phys = NULL;
+#ifdef CONFIG_SCHED_MC
+ struct sched_group *sched_group_core = NULL;
+#endif
#ifdef CONFIG_NUMA
struct sched_group **sched_group_nodes = NULL;
struct sched_group *sched_group_allnodes = NULL;
@@ -6171,6 +6187,18 @@ static int build_sched_domains(const cpu
cpus_and(sd->span, sd->span, *cpu_map);
#endif
+ if (!sched_group_phys) {
+ sched_group_phys
+ = kmalloc(sizeof(struct sched_group) * NR_CPUS,
+ GFP_KERNEL);
+ if (!sched_group_phys) {
+ printk (KERN_WARNING "Can not alloc phys sched"
+ "group\n");
+ goto error;
+ }
+ sched_group_phys_bycpu[i] = sched_group_phys;
+ }
+
p = sd;
sd = &per_cpu(phys_domains, i);
group = cpu_to_phys_group(i);
@@ -6180,6 +6208,18 @@ static int build_sched_domains(const cpu
sd->groups = &sched_group_phys[group];
#ifdef CONFIG_SCHED_MC
+ if (!sched_group_core) {
+ sched_group_core
+ = kmalloc(sizeof(struct sched_group) * NR_CPUS,
+ GFP_KERNEL);
+ if (!sched_group_core) {
+ printk (KERN_WARNING "Can not alloc core sched"
+ "group\n");
+ goto error;
+ }
+ sched_group_core_bycpu[i] = sched_group_core;
+ }
+
p = sd;
sd = &per_cpu(core_domains, i);
group = cpu_to_core_group(i);
@@ -6375,11 +6415,9 @@ static int build_sched_domains(const cpu
return 0;
-#ifdef CONFIG_NUMA
error:
free_sched_groups(cpu_map);
return -ENOMEM;
-#endif
}
/*
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
_
--
Regards,
vatsa
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