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authorMiao Xie <miaox@cn.fujitsu.com>2010-03-23 13:35:34 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-04-01 15:58:46 -0700
commit893b328f07c17aa84f562fc5566eb524bd76188e (patch)
tree6ee34077dea0834d5952d8696c60bd9543747553 /kernel
parentfa8e8558a6874707d8e30c85bb386f43cb61a6e1 (diff)
cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
commit 5ab116c9349ef52d6fbd2e2917a53f13194b048e upstream. cpuset_mem_spread_node() returns an offline node, and causes an oops. This patch fixes it by initializing task->mems_allowed to node_states[N_HIGH_MEMORY], and updating task->mems_allowed when doing memory hotplug. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Reported-by: Nick Piggin <npiggin@suse.de> Tested-by: Nick Piggin <npiggin@suse.de> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c20
-rw-r--r--kernel/kthread.c2
2 files changed, 13 insertions, 9 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 39e5121a78a6..a81a91010c9f 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -921,9 +921,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
* call to guarantee_online_mems(), as we know no one is changing
* our task's cpuset.
*
- * Hold callback_mutex around the two modifications of our tasks
- * mems_allowed to synchronize with cpuset_mems_allowed().
- *
* While the mm_struct we are migrating is typically from some
* other task, the task_struct mems_allowed that we are hacking
* is for our current task, which must allocate new pages for that
@@ -1392,11 +1389,10 @@ static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
if (cs == &top_cpuset) {
cpumask_copy(cpus_attach, cpu_possible_mask);
- to = node_possible_map;
} else {
guarantee_online_cpus(cs, cpus_attach);
- guarantee_online_mems(cs, &to);
}
+ guarantee_online_mems(cs, &to);
/* do per-task migration stuff possibly for each in the threadgroup */
cpuset_attach_task(tsk, &to, cs);
@@ -2091,15 +2087,23 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
static int cpuset_track_online_nodes(struct notifier_block *self,
unsigned long action, void *arg)
{
+ nodemask_t oldmems;
+
cgroup_lock();
switch (action) {
case MEM_ONLINE:
- case MEM_OFFLINE:
+ oldmems = top_cpuset.mems_allowed;
mutex_lock(&callback_mutex);
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
mutex_unlock(&callback_mutex);
- if (action == MEM_OFFLINE)
- scan_for_empty_cpusets(&top_cpuset);
+ update_tasks_nodemask(&top_cpuset, &oldmems, NULL);
+ break;
+ case MEM_OFFLINE:
+ /*
+ * needn't update top_cpuset.mems_allowed explicitly because
+ * scan_for_empty_cpusets() will update it.
+ */
+ scan_for_empty_cpusets(&top_cpuset);
break;
default:
break;
diff --git a/kernel/kthread.c b/kernel/kthread.c
index ab7ae57773e1..84027cfffccf 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -196,7 +196,7 @@ int kthreadd(void *unused)
set_task_comm(tsk, "kthreadd");
ignore_signals(tsk);
set_cpus_allowed_ptr(tsk, cpu_all_mask);
- set_mems_allowed(node_possible_map);
+ set_mems_allowed(node_states[N_HIGH_MEMORY]);
current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;