path: root/kernel/cpuset.c
diff options
authorMiao Xie <miaox@cn.fujitsu.com>2009-01-07 18:08:40 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-08 08:31:11 -0800
commitf5813d94279a18ff5936d675e24b44b44a571197 (patch)
tree0c565bd5535f0f5623984e65403bda9c41b3a148 /kernel/cpuset.c
parent13337714f3b0307dc7f75ef5d83ecf0db2abbd65 (diff)
cpusets: set task's cpu_allowed to cpu_possible_map when attaching it into top cpuset
I found a bug on my dual-cpu box. I created a sub cpuset in top cpuset and assign 1 to its cpus. And then we attach some tasks into this sub cpuset. After this, we offline CPU1. Now, the tasks in this new cpuset are moved into top cpuset automatically because there is no cpu in sub cpuset. Then we online CPU1, we find all the tasks which doesn't belong to top cpuset originally just run on CPU0. We fix this bug by setting task's cpu_allowed to cpu_possible_map when attaching it into top cpuset. This method needn't modify the current behavior of cpusets on CPU hotplug, and all of tasks in top cpuset use cpu_possible_map to initialize their cpu_allowed. Signed-off-by: Miao Xie <miaox@cn.fujitsu.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>
Diffstat (limited to 'kernel/cpuset.c')
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index a841b5c01ef..6012e326e85 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1338,10 +1338,14 @@ static void cpuset_attach(struct cgroup_subsys *ss,
struct cpuset *oldcs = cgroup_cs(oldcont);
int err;
- mutex_lock(&callback_mutex);
- guarantee_online_cpus(cs, &cpus);
+ if (cs == &top_cpuset) {
+ cpus = cpu_possible_map;
+ } else {
+ mutex_lock(&callback_mutex);
+ guarantee_online_cpus(cs, &cpus);
+ mutex_unlock(&callback_mutex);
+ }
err = set_cpus_allowed_ptr(tsk, &cpus);
- mutex_unlock(&callback_mutex);
if (err)