Commit 36938169 authored by Srivatsa Vaddagiri's avatar Srivatsa Vaddagiri Committed by Linus Torvalds
Browse files

[PATCH] sched_domai: Allocate sched_group structures dynamically 

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
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: default avatarSrivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 15f0b676

kernel/sched.c

+43 −5
Original line number Diff line number Diff line
@@ -5747,7 +5747,7 @@ 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)
@@ -5763,7 +5763,7 @@ 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)
@@ -5823,9 +5823,9 @@ 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
@@ -5863,6 +5863,18 @@ 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

	}

}



/*
@@ -5872,6 +5884,10 @@ 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;
@@ -5930,6 +5946,18 @@ static int build_sched_domains(const cpumask_t *cpu_map) 
		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);
@@ -5939,6 +5967,18 @@ static int build_sched_domains(const cpumask_t *cpu_map) 
		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);
@@ -6134,11 +6174,9 @@ static int build_sched_domains(const cpumask_t *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.

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