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Commit 2341d1b6 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

cpuset: convert cpuset_attach() to use cpumask_var_t 



Impact: reduce stack usage

Allocate a global cpumask_var_t at boot, and use it in cpuset_attach(), so
we won't fail cpuset_attach().

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarMike Travis <travis@sgi.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5771f0a2

kernel/cpuset.c

+9 −5
Original line number Diff line number Diff line
@@ -1306,6 +1306,9 @@ static int fmeter_getrate(struct fmeter *fmp) 
	return val;

}



/* Protected by cgroup_lock */

static cpumask_var_t cpus_attach;



/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */

static int cpuset_can_attach(struct cgroup_subsys *ss,

			     struct cgroup *cont, struct task_struct *tsk)
@@ -1330,7 +1333,6 @@ static void cpuset_attach(struct cgroup_subsys *ss, 
			  struct cgroup *cont, struct cgroup *oldcont,

			  struct task_struct *tsk)

{

	cpumask_t cpus;

	nodemask_t from, to;

	struct mm_struct *mm;

	struct cpuset *cs = cgroup_cs(cont);
@@ -1338,13 +1340,13 @@ static void cpuset_attach(struct cgroup_subsys *ss, 
	int err;



	if (cs == &top_cpuset) {

		cpus = cpu_possible_map;

		cpumask_copy(cpus_attach, cpu_possible_mask);

	} else {

		mutex_lock(&callback_mutex);

		guarantee_online_cpus(cs, &cpus);

		guarantee_online_cpus(cs, cpus_attach);

		mutex_unlock(&callback_mutex);

	}

	err = set_cpus_allowed_ptr(tsk, &cpus);

	err = set_cpus_allowed_ptr(tsk, cpus_attach);

	if (err)

		return;
@@ -1357,7 +1359,6 @@ static void cpuset_attach(struct cgroup_subsys *ss, 
			cpuset_migrate_mm(mm, &from, &to);

		mmput(mm);

	}



}



/* The various types of files and directories in a cpuset file system */
@@ -1838,6 +1839,9 @@ int __init cpuset_init(void) 
	if (err < 0)

		return err;



	if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL))

		BUG();



	number_of_cpusets = 1;

	return 0;

}