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: Li Zefan <lizf@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Mike Travis <travis@sgi.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index afa29cf..1e32e6b 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1306,6 +1306,9 @@
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 @@
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 @@
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 @@
cpuset_migrate_mm(mm, &from, &to);
mmput(mm);
}
-
}
/* The various types of files and directories in a cpuset file system */
@@ -1838,6 +1839,9 @@
if (err < 0)
return err;
+ if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL))
+ BUG();
+
number_of_cpusets = 1;
return 0;
}