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Commit 4cb98839 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Avoid allocations in sched_domain_debug() 



Since we're all serialized by sched_domains_mutex we can use
sched_domains_tmpmask and avoid having to do allocations. This means
we can use sched_domains_debug() for cpu_attach_domain() again.

Signed-off-by: default avatarPeter 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/20110407122942.664347467@chello.nl


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f96225fd

kernel/sched.c

+5 −12
Original line number Diff line number Diff line
@@ -6395,6 +6395,8 @@ early_initcall(migration_init); 


#ifdef CONFIG_SMP



static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */



#ifdef CONFIG_SCHED_DEBUG



static __read_mostly int sched_domain_debug_enabled;
@@ -6490,7 +6492,6 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 


static void sched_domain_debug(struct sched_domain *sd, int cpu)

{

	cpumask_var_t groupmask;

	int level = 0;



	if (!sched_domain_debug_enabled)
@@ -6503,20 +6504,14 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu) 


	printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);



	if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {

		printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");

		return;

	}



	for (;;) {

		if (sched_domain_debug_one(sd, cpu, level, groupmask))

		if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))

			break;

		level++;

		sd = sd->parent;

		if (!sd)

			break;

	}

	free_cpumask_var(groupmask);

}

#else /* !CONFIG_SCHED_DEBUG */

# define sched_domain_debug(sd, cpu) do { } while (0)
@@ -6721,7 +6716,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) 
			sd->child = NULL;

	}



	/* sched_domain_debug(sd, cpu); */

	sched_domain_debug(sd, cpu);



	rq_attach_root(rq, rd);

	tmp = rq->sd;
@@ -6851,8 +6846,6 @@ static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) 
	return cpu;

}



static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */



/*

 * build_sched_groups takes the cpumask we wish to span, and a pointer

 * to a function which identifies what group(along with sched group) a CPU
@@ -7896,8 +7889,8 @@ void __init sched_init(void) 


	/* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */

	zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);

	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);

#ifdef CONFIG_SMP

	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);

#ifdef CONFIG_NO_HZ

	zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);

	alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT);