Commit 0b2f630a authored by Miao Xie's avatar Miao Xie Committed by Linus Torvalds
Browse files

cpusets: restructure the function update_cpumask() and update_nodemask() 



Extract two functions from update_cpumask() and update_nodemask().They
will be used later for updating tasks' cpus_allowed and mems_allowed after
CPU/NODE offline/online.

[lizf@cn.fujitsu.com: build fix]
Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Acked-by: default avatarPaul Jackson <pj@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc:  Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 628f4235

kernel/cpuset.c

+109 −72
Original line number Diff line number Diff line
@@ -763,6 +763,37 @@ static void cpuset_change_cpumask(struct task_struct *tsk, 
	set_cpus_allowed_ptr(tsk, &((cgroup_cs(scan->cg))->cpus_allowed));

}



/**

 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.

 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed

 *

 * Called with cgroup_mutex held

 *

 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,

 * calling callback functions for each.

 *

 * Return 0 if successful, -errno if not.

 */

static int update_tasks_cpumask(struct cpuset *cs)

{

	struct cgroup_scanner scan;

	struct ptr_heap heap;

	int retval;



	retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after);

	if (retval)

		return retval;



	scan.cg = cs->css.cgroup;

	scan.test_task = cpuset_test_cpumask;

	scan.process_task = cpuset_change_cpumask;

	scan.heap = &heap;

	retval = cgroup_scan_tasks(&scan);



	heap_free(&heap);

	return retval;

}



/**

 * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it

 * @cs: the cpuset to consider
@@ -771,8 +802,6 @@ static void cpuset_change_cpumask(struct task_struct *tsk, 
static int update_cpumask(struct cpuset *cs, const char *buf)

{

	struct cpuset trialcs;

	struct cgroup_scanner scan;

	struct ptr_heap heap;

	int retval;

	int is_load_balanced;
@@ -806,10 +835,6 @@ static int update_cpumask(struct cpuset *cs, const char *buf) 
	if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed))

		return 0;



	retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after);

	if (retval)

		return retval;



	is_load_balanced = is_sched_load_balance(&trialcs);



	mutex_lock(&callback_mutex);
@@ -820,12 +845,9 @@ static int update_cpumask(struct cpuset *cs, const char *buf) 
	 * Scan tasks in the cpuset, and update the cpumasks of any

	 * that need an update.

	 */

	scan.cg = cs->css.cgroup;

	scan.test_task = cpuset_test_cpumask;

	scan.process_task = cpuset_change_cpumask;

	scan.heap = &heap;

	cgroup_scan_tasks(&scan);

	heap_free(&heap);

	retval = update_tasks_cpumask(cs);

	if (retval < 0)

		return retval;



	if (is_load_balanced)

		rebuild_sched_domains();
@@ -881,73 +903,25 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, 
	mutex_unlock(&callback_mutex);

}



/*

 * Handle user request to change the 'mems' memory placement

 * of a cpuset.  Needs to validate the request, update the

 * cpusets mems_allowed and mems_generation, and for each

 * task in the cpuset, rebind any vma mempolicies and if

 * the cpuset is marked 'memory_migrate', migrate the tasks

 * pages to the new memory.

 *

 * Call with cgroup_mutex held.  May take callback_mutex during call.

 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,

 * lock each such tasks mm->mmap_sem, scan its vma's and rebind

 * their mempolicies to the cpusets new mems_allowed.

 */



static void *cpuset_being_rebound;



static int update_nodemask(struct cpuset *cs, const char *buf)

/**

 * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.

 * @cs: the cpuset in which each task's mems_allowed mask needs to be changed

 * @oldmem: old mems_allowed of cpuset cs

 *

 * Called with cgroup_mutex held

 * Return 0 if successful, -errno if not.

 */

static int update_tasks_nodemask(struct cpuset *cs, const nodemask_t *oldmem)

{

	struct cpuset trialcs;

	nodemask_t oldmem;

	struct task_struct *p;

	struct mm_struct **mmarray;

	int i, n, ntasks;

	int migrate;

	int fudge;

	int retval;

	struct cgroup_iter it;



	/*

	 * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];

	 * it's read-only

	 */

	if (cs == &top_cpuset)

		return -EACCES;



	trialcs = *cs;



	/*

	 * An empty mems_allowed is ok iff there are no tasks in the cpuset.

	 * Since nodelist_parse() fails on an empty mask, we special case

	 * that parsing.  The validate_change() call ensures that cpusets

	 * with tasks have memory.

	 */

	if (!*buf) {

		nodes_clear(trialcs.mems_allowed);

	} else {

		retval = nodelist_parse(buf, trialcs.mems_allowed);

		if (retval < 0)

			goto done;



		if (!nodes_subset(trialcs.mems_allowed,

				node_states[N_HIGH_MEMORY]))

			return -EINVAL;

	}

	oldmem = cs->mems_allowed;

	if (nodes_equal(oldmem, trialcs.mems_allowed)) {

		retval = 0;		/* Too easy - nothing to do */

		goto done;

	}

	retval = validate_change(cs, &trialcs);

	if (retval < 0)

		goto done;



	mutex_lock(&callback_mutex);

	cs->mems_allowed = trialcs.mems_allowed;

	cs->mems_generation = cpuset_mems_generation++;

	mutex_unlock(&callback_mutex);

	int retval;



	cpuset_being_rebound = cs;		/* causes mpol_dup() rebind */
@@ -1014,7 +988,7 @@ static int update_nodemask(struct cpuset *cs, const char *buf) 


		mpol_rebind_mm(mm, &cs->mems_allowed);

		if (migrate)

			cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);

			cpuset_migrate_mm(mm, oldmem, &cs->mems_allowed);

		mmput(mm);

	}
@@ -1026,6 +1000,70 @@ done: 
	return retval;

}



/*

 * Handle user request to change the 'mems' memory placement

 * of a cpuset.  Needs to validate the request, update the

 * cpusets mems_allowed and mems_generation, and for each

 * task in the cpuset, rebind any vma mempolicies and if

 * the cpuset is marked 'memory_migrate', migrate the tasks

 * pages to the new memory.

 *

 * Call with cgroup_mutex held.  May take callback_mutex during call.

 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,

 * lock each such tasks mm->mmap_sem, scan its vma's and rebind

 * their mempolicies to the cpusets new mems_allowed.

 */

static int update_nodemask(struct cpuset *cs, const char *buf)

{

	struct cpuset trialcs;

	nodemask_t oldmem;

	int retval;



	/*

	 * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];

	 * it's read-only

	 */

	if (cs == &top_cpuset)

		return -EACCES;



	trialcs = *cs;



	/*

	 * An empty mems_allowed is ok iff there are no tasks in the cpuset.

	 * Since nodelist_parse() fails on an empty mask, we special case

	 * that parsing.  The validate_change() call ensures that cpusets

	 * with tasks have memory.

	 */

	if (!*buf) {

		nodes_clear(trialcs.mems_allowed);

	} else {

		retval = nodelist_parse(buf, trialcs.mems_allowed);

		if (retval < 0)

			goto done;



		if (!nodes_subset(trialcs.mems_allowed,

				node_states[N_HIGH_MEMORY]))

			return -EINVAL;

	}

	oldmem = cs->mems_allowed;

	if (nodes_equal(oldmem, trialcs.mems_allowed)) {

		retval = 0;		/* Too easy - nothing to do */

		goto done;

	}

	retval = validate_change(cs, &trialcs);

	if (retval < 0)

		goto done;



	mutex_lock(&callback_mutex);

	cs->mems_allowed = trialcs.mems_allowed;

	cs->mems_generation = cpuset_mems_generation++;

	mutex_unlock(&callback_mutex);



	retval = update_tasks_nodemask(cs, &oldmem);

done:

	return retval;

}



int current_cpuset_is_being_rebound(void)

{

	return task_cs(current) == cpuset_being_rebound;
@@ -1935,7 +1973,6 @@ void __init cpuset_init_smp(void) 
}



/**



 * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.

 * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.

 * @pmask: pointer to cpumask_t variable to receive cpus_allowed set.

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