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Commit aeed6824 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

cpuset: clean up cpuset hierarchy traversal code 



Use cpuset.stack_list rather than kfifo, so we avoid memory allocation
for kfifo.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 93a65575

kernel/cpuset.c

+8 −13
Original line number Original line Diff line number Diff line
@@ -54,7 +54,6 @@ 
#include <asm/uaccess.h>

#include <asm/uaccess.h>

#include <asm/atomic.h>

#include <asm/atomic.h>

#include <linux/mutex.h>

#include <linux/mutex.h>

#include <linux/kfifo.h>

#include <linux/workqueue.h>

#include <linux/workqueue.h>

#include <linux/cgroup.h>

#include <linux/cgroup.h>
@@ -557,7 +556,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c) 
 * So the reverse nesting would risk an ABBA deadlock.

 * So the reverse nesting would risk an ABBA deadlock.

 *

 *

 * The three key local variables below are:

 * The three key local variables below are:

 *    q  - a kfifo queue of cpuset pointers, used to implement a

 *    q  - a linked-list queue of cpuset pointers, used to implement a

 *	   top-down scan of all cpusets.  This scan loads a pointer

 *	   top-down scan of all cpusets.  This scan loads a pointer

 *	   to each cpuset marked is_sched_load_balance into the

 *	   to each cpuset marked is_sched_load_balance into the

 *	   array 'csa'.  For our purposes, rebuilding the schedulers

 *	   array 'csa'.  For our purposes, rebuilding the schedulers
@@ -592,7 +591,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c) 




void rebuild_sched_domains(void)

void rebuild_sched_domains(void)

{

{

	struct kfifo *q;	/* queue of cpusets to be scanned */

	LIST_HEAD(q);		/* queue of cpusets to be scanned*/

	struct cpuset *cp;	/* scans q */

	struct cpuset *cp;	/* scans q */

	struct cpuset **csa;	/* array of all cpuset ptrs */

	struct cpuset **csa;	/* array of all cpuset ptrs */

	int csn;		/* how many cpuset ptrs in csa so far */

	int csn;		/* how many cpuset ptrs in csa so far */
@@ -602,7 +601,6 @@ void rebuild_sched_domains(void) 
	int ndoms;		/* number of sched domains in result */

	int ndoms;		/* number of sched domains in result */

	int nslot;		/* next empty doms[] cpumask_t slot */

	int nslot;		/* next empty doms[] cpumask_t slot */





	q = NULL;

	csa = NULL;

	csa = NULL;

	doms = NULL;

	doms = NULL;

	dattr = NULL;

	dattr = NULL;
@@ -622,20 +620,19 @@ void rebuild_sched_domains(void) 
		goto rebuild;

		goto rebuild;

	}

	}





	q = kfifo_alloc(number_of_cpusets * sizeof(cp), GFP_KERNEL, NULL);

	if (IS_ERR(q))

		goto done;

	csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);

	csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);

	if (!csa)

	if (!csa)

		goto done;

		goto done;

	csn = 0;

	csn = 0;





	cp = &top_cpuset;

	list_add(&top_cpuset.stack_list, &q);

	__kfifo_put(q, (void *)&cp, sizeof(cp));

	while (!list_empty(&q)) {

	while (__kfifo_get(q, (void *)&cp, sizeof(cp))) {

		struct cgroup *cont;

		struct cgroup *cont;

		struct cpuset *child;   /* scans child cpusets of cp */

		struct cpuset *child;   /* scans child cpusets of cp */





		cp = list_first_entry(&q, struct cpuset, stack_list);

		list_del(q.next);



		if (cpus_empty(cp->cpus_allowed))

		if (cpus_empty(cp->cpus_allowed))

			continue;

			continue;
@@ -652,7 +649,7 @@ void rebuild_sched_domains(void) 




		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {

		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {

			child = cgroup_cs(cont);

			child = cgroup_cs(cont);

			__kfifo_put(q, (void *)&child, sizeof(cp));

			list_add_tail(&child->stack_list, &q);

		}

		}

  	}

  	}
@@ -735,8 +732,6 @@ void rebuild_sched_domains(void) 
	put_online_cpus();

	put_online_cpus();





done:

done:

	if (q && !IS_ERR(q))

		kfifo_free(q);

	kfree(csa);

	kfree(csa);

	/* Don't kfree(doms) -- partition_sched_domains() does that. */

	/* Don't kfree(doms) -- partition_sched_domains() does that. */

	/* Don't kfree(dattr) -- partition_sched_domains() does that. */

	/* Don't kfree(dattr) -- partition_sched_domains() does that. */