Andrew/Nick/Ingo,
Here's a different version of the patch that tries to handle mem
allocation failures in build_sched_domains by bailing out and cleaning up
thus-far allocated memory. The patch has a direct consequence that we disable
load balancing completely (even at sibling level) upon *any* memory allocation
failure. Is that acceptable?
Patch (against 2.6.16-mm2) to handle memory allocation failure in
build_sched_domains.
Signed-off-by: Srivatsa Vaddagir <[email protected]>
diff -puN kernel/sched.c~sd_handle_error kernel/sched.c
--- linux-2.6.16-mm2/kernel/sched.c~sd_handle_error 2006-04-01 23:36:43.000000000 +0530
+++ linux-2.6.16-mm2-root/kernel/sched.c 2006-04-01 23:37:35.000000000 +0530
@@ -6061,11 +6061,56 @@ next_sg:
}
#endif
+/* Free memory allocated for various sched_group structures */
+static void free_sched_groups(const cpumask_t *cpu_map)
+{
+#ifdef CONFIG_NUMA
+ int i;
+ int cpu;
+
+ 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 (!sched_group_nodes)
+ continue;
+
+ 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;
+ }
+ kfree(sched_group_nodes);
+ sched_group_nodes_bycpu[cpu] = NULL;
+ }
+#endif
+}
+
/*
* Build sched domains for a given set of cpus and attach the sched domains
* to the individual cpus
*/
-void build_sched_domains(const cpumask_t *cpu_map)
+static int build_sched_domains(const cpumask_t *cpu_map)
{
int i;
#ifdef CONFIG_NUMA
@@ -6075,11 +6120,11 @@ void build_sched_domains(const cpumask_t
/*
* Allocate the per-node list of sched groups
*/
- sched_group_nodes = kmalloc(sizeof(struct sched_group*)*MAX_NUMNODES,
+ sched_group_nodes = kzalloc(sizeof(struct sched_group*)*MAX_NUMNODES,
GFP_ATOMIC);
if (!sched_group_nodes) {
printk(KERN_WARNING "Can not alloc sched group node list\n");
- return;
+ return -ENOMEM;
}
sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
#endif
@@ -6105,7 +6150,7 @@ void build_sched_domains(const cpumask_t
if (!sched_group_allnodes) {
printk(KERN_WARNING
"Can not alloc allnodes sched group\n");
- break;
+ goto error;
}
sched_group_allnodes_bycpu[i]
= sched_group_allnodes;
@@ -6219,23 +6264,20 @@ void build_sched_domains(const cpumask_t
cpus_and(domainspan, domainspan, *cpu_map);
sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL);
+ if (!sg) {
+ printk(KERN_WARNING
+ "Can not alloc domain group for node %d\n", i);
+ goto error;
+ }
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;
+ sg->next = sg;
cpus_or(covered, covered, nodemask);
prev = sg;
@@ -6258,15 +6300,15 @@ void build_sched_domains(const cpumask_t
if (!sg) {
printk(KERN_WARNING
"Can not alloc domain group for node %d\n", j);
- break;
+ goto error;
}
sg->cpu_power = 0;
sg->cpumask = tmp;
+ sg->next = prev;
cpus_or(covered, covered, tmp);
prev->next = sg;
prev = sg;
}
- prev->next = sched_group_nodes[i];
}
#endif
@@ -6329,13 +6371,22 @@ void build_sched_domains(const cpumask_t
* Tune cache-hot values:
*/
calibrate_migration_costs(cpu_map);
+
+ 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.
*/
-static void arch_init_sched_domains(const cpumask_t *cpu_map)
+static int arch_init_sched_domains(const cpumask_t *cpu_map)
{
cpumask_t cpu_default_map;
+ int err;
/*
* Setup mask for cpus without special case scheduling requirements.
@@ -6344,51 +6395,14 @@ static void arch_init_sched_domains(cons
*/
cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map);
- build_sched_domains(&cpu_default_map);
+ err = build_sched_domains(&cpu_default_map);
+
+ return err;
}
static void arch_destroy_sched_domains(const cpumask_t *cpu_map)
{
-#ifdef CONFIG_NUMA
- int i;
- int cpu;
-
- 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 (!sched_group_nodes)
- continue;
-
- 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;
- }
- kfree(sched_group_nodes);
- sched_group_nodes_bycpu[cpu] = NULL;
- }
-#endif
+ free_sched_groups(cpu_map);
}
/*
@@ -6413,9 +6427,10 @@ static void detach_destroy_domains(const
* correct sched domains
* Call with hotplug lock held
*/
-void partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2)
+int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2)
{
cpumask_t change_map;
+ int err = 0;
cpus_and(*partition1, *partition1, cpu_online_map);
cpus_and(*partition2, *partition2, cpu_online_map);
@@ -6424,9 +6439,11 @@ void partition_sched_domains(cpumask_t *
/* Detach sched domains from all of the affected cpus */
detach_destroy_domains(&change_map);
if (!cpus_empty(*partition1))
- build_sched_domains(partition1);
- if (!cpus_empty(*partition2))
- build_sched_domains(partition2);
+ err = build_sched_domains(partition1);
+ if (!err && !cpus_empty(*partition2))
+ err = build_sched_domains(partition2);
+
+ return err;
}
#ifdef CONFIG_HOTPLUG_CPU
diff -puN include/linux/sched.h~sd_handle_error include/linux/sched.h
--- linux-2.6.16-mm2/include/linux/sched.h~sd_handle_error 2006-04-01 23:36:43.000000000 +0530
+++ linux-2.6.16-mm2-root/include/linux/sched.h 2006-04-01 23:36:43.000000000 +0530
@@ -632,7 +632,7 @@ struct sched_domain {
#endif
};
-extern void partition_sched_domains(cpumask_t *partition1,
+extern int partition_sched_domains(cpumask_t *partition1,
cpumask_t *partition2);
/*
_
--
Regards,
vatsa
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
