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Commit bf92370c authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
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cpuset: Simply allocation and freeing of cpumasks 



The previous commit introduces a new subparts_cpus mask into the cpuset
data structure and a new tmpmasks structure.  Managing the allocation
and freeing of those cpumasks is becoming more complex.

So a number of helper functions are added to simplify and streamline
the management of those cpumasks. To make it simple, all the cpumasks
are now pre-cleared on allocation.

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 58b74842

kernel/cgroup/cpuset.c

+77 −33
Original line number Diff line number Diff line
@@ -455,6 +455,65 @@ static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) 
		is_mem_exclusive(p) <= is_mem_exclusive(q);

}



/**

 * alloc_cpumasks - allocate three cpumasks for cpuset

 * @cs:  the cpuset that have cpumasks to be allocated.

 * @tmp: the tmpmasks structure pointer

 * Return: 0 if successful, -ENOMEM otherwise.

 *

 * Only one of the two input arguments should be non-NULL.

 */

static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)

{

	cpumask_var_t *pmask1, *pmask2, *pmask3;



	if (cs) {

		pmask1 = &cs->cpus_allowed;

		pmask2 = &cs->effective_cpus;

		pmask3 = &cs->subparts_cpus;

	} else {

		pmask1 = &tmp->new_cpus;

		pmask2 = &tmp->addmask;

		pmask3 = &tmp->delmask;

	}



	if (!zalloc_cpumask_var(pmask1, GFP_KERNEL))

		return -ENOMEM;



	if (!zalloc_cpumask_var(pmask2, GFP_KERNEL))

		goto free_one;



	if (!zalloc_cpumask_var(pmask3, GFP_KERNEL))

		goto free_two;



	return 0;



free_two:

	free_cpumask_var(*pmask2);

free_one:

	free_cpumask_var(*pmask1);

	return -ENOMEM;

}



/**

 * free_cpumasks - free cpumasks in a tmpmasks structure

 * @cs:  the cpuset that have cpumasks to be free.

 * @tmp: the tmpmasks structure pointer

 */

static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)

{

	if (cs) {

		free_cpumask_var(cs->cpus_allowed);

		free_cpumask_var(cs->effective_cpus);

		free_cpumask_var(cs->subparts_cpus);

	}

	if (tmp) {

		free_cpumask_var(tmp->new_cpus);

		free_cpumask_var(tmp->addmask);

		free_cpumask_var(tmp->delmask);

	}

}



/**

 * alloc_trial_cpuset - allocate a trial cpuset

 * @cs: the cpuset that the trial cpuset duplicates
@@ -467,31 +526,24 @@ static struct cpuset *alloc_trial_cpuset(struct cpuset *cs) 
	if (!trial)

		return NULL;



	if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL))

		goto free_cs;

	if (!alloc_cpumask_var(&trial->effective_cpus, GFP_KERNEL))

		goto free_cpus;

	if (alloc_cpumasks(trial, NULL)) {

		kfree(trial);

		return NULL;

	}



	cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);

	cpumask_copy(trial->effective_cpus, cs->effective_cpus);

	return trial;



free_cpus:

	free_cpumask_var(trial->cpus_allowed);

free_cs:

	kfree(trial);

	return NULL;

}



/**

 * free_trial_cpuset - free the trial cpuset

 * @trial: the trial cpuset to be freed

 * free_cpuset - free the cpuset

 * @cs: the cpuset to be freed

 */

static void free_trial_cpuset(struct cpuset *trial)

static inline void free_cpuset(struct cpuset *cs)

{

	free_cpumask_var(trial->effective_cpus);

	free_cpumask_var(trial->cpus_allowed);

	kfree(trial);

	free_cpumasks(cs, NULL);

	kfree(cs);

}



/*
@@ -1385,7 +1437,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, 
	if (spread_flag_changed)

		update_tasks_flags(cs);

out:

	free_trial_cpuset(trialcs);

	free_cpuset(trialcs);

	return err;

}
@@ -1769,7 +1821,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, 
		break;

	}



	free_trial_cpuset(trialcs);

	free_cpuset(trialcs);

out_unlock:

	mutex_unlock(&cpuset_mutex);

	kernfs_unbreak_active_protection(of->kn);
@@ -2024,26 +2076,19 @@ cpuset_css_alloc(struct cgroup_subsys_state *parent_css) 
	cs = kzalloc(sizeof(*cs), GFP_KERNEL);

	if (!cs)

		return ERR_PTR(-ENOMEM);

	if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL))

		goto free_cs;

	if (!alloc_cpumask_var(&cs->effective_cpus, GFP_KERNEL))

		goto free_cpus;



	if (alloc_cpumasks(cs, NULL)) {

		kfree(cs);

		return ERR_PTR(-ENOMEM);

	}



	set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);

	cpumask_clear(cs->cpus_allowed);

	nodes_clear(cs->mems_allowed);

	cpumask_clear(cs->effective_cpus);

	nodes_clear(cs->effective_mems);

	fmeter_init(&cs->fmeter);

	cs->relax_domain_level = -1;



	return &cs->css;



free_cpus:

	free_cpumask_var(cs->cpus_allowed);

free_cs:

	kfree(cs);

	return ERR_PTR(-ENOMEM);

}



static int cpuset_css_online(struct cgroup_subsys_state *css)
@@ -2134,9 +2179,7 @@ static void cpuset_css_free(struct cgroup_subsys_state *css) 
{

	struct cpuset *cs = css_cs(css);



	free_cpumask_var(cs->effective_cpus);

	free_cpumask_var(cs->cpus_allowed);

	kfree(cs);

	free_cpuset(cs);

}



static void cpuset_bind(struct cgroup_subsys_state *root_css)
@@ -2200,6 +2243,7 @@ int __init cpuset_init(void) 


	BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));

	BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));

	BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));



	cpumask_setall(top_cpuset.cpus_allowed);

	nodes_setall(top_cpuset.mems_allowed);