Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 151a4420 authored by Paul Jackson's avatar Paul Jackson Committed by Linus Torvalds
Browse files

[PATCH] cpuset: don't need to mark cpuset_mems_generation atomic 



Drop the atomic_t marking on the cpuset static global
cpuset_mems_generation.  Since all access to it is guarded by the global
manage_mutex, there is no need for further serialization of this value.

Signed-off-by: default avatarPaul Jackson <pj@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8488bc35

kernel/cpuset.c

+11 −8
Original line number Diff line number Diff line
@@ -149,7 +149,7 @@ static inline int is_spread_slab(const struct cpuset *cs) 
}



/*

 * Increment this atomic integer everytime any cpuset changes its

 * Increment this integer everytime any cpuset changes its

 * mems_allowed value.  Users of cpusets can track this generation

 * number, and avoid having to lock and reload mems_allowed unless

 * the cpuset they're using changes generation.
@@ -163,8 +163,11 @@ static inline int is_spread_slab(const struct cpuset *cs) 
 * on every visit to __alloc_pages(), to efficiently check whether

 * its current->cpuset->mems_allowed has changed, requiring an update

 * of its current->mems_allowed.

 *

 * Since cpuset_mems_generation is guarded by manage_mutex,

 * there is no need to mark it atomic.

 */

static atomic_t cpuset_mems_generation = ATOMIC_INIT(1);

static int cpuset_mems_generation;



static struct cpuset top_cpuset = {

	.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
@@ -877,7 +880,7 @@ static int update_nodemask(struct cpuset *cs, char *buf) 


	mutex_lock(&callback_mutex);

	cs->mems_allowed = trialcs.mems_allowed;

	cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);

	cs->mems_generation = cpuset_mems_generation++;

	mutex_unlock(&callback_mutex);



	set_cpuset_being_rebound(cs);		/* causes mpol_copy() rebind */
@@ -1270,11 +1273,11 @@ static ssize_t cpuset_common_file_write(struct file *file, const char __user *us 
		break;

	case FILE_SPREAD_PAGE:

		retval = update_flag(CS_SPREAD_PAGE, cs, buffer);

		cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);

		cs->mems_generation = cpuset_mems_generation++;

		break;

	case FILE_SPREAD_SLAB:

		retval = update_flag(CS_SPREAD_SLAB, cs, buffer);

		cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);

		cs->mems_generation = cpuset_mems_generation++;

		break;

	case FILE_TASKLIST:

		retval = attach_task(cs, buffer, &pathbuf);
@@ -1823,7 +1826,7 @@ static long cpuset_create(struct cpuset *parent, const char *name, int mode) 
	atomic_set(&cs->count, 0);

	INIT_LIST_HEAD(&cs->sibling);

	INIT_LIST_HEAD(&cs->children);

	cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);

	cs->mems_generation = cpuset_mems_generation++;

	fmeter_init(&cs->fmeter);



	cs->parent = parent;
@@ -1913,7 +1916,7 @@ int __init cpuset_init_early(void) 
	struct task_struct *tsk = current;



	tsk->cpuset = &top_cpuset;

	tsk->cpuset->mems_generation = atomic_inc_return(&cpuset_mems_generation);

	tsk->cpuset->mems_generation = cpuset_mems_generation++;

	return 0;

}
@@ -1932,7 +1935,7 @@ int __init cpuset_init(void) 
	top_cpuset.mems_allowed = NODE_MASK_ALL;



	fmeter_init(&top_cpuset.fmeter);

	top_cpuset.mems_generation = atomic_inc_return(&cpuset_mems_generation);

	top_cpuset.mems_generation = cpuset_mems_generation++;



	init_task.cpuset = &top_cpuset;