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cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node

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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>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Miao Xie 2010-03-23 13:35:34 -07:00 committed by Linus Torvalds
parent 5574169613
commit 5ab116c934
3 changed files with 14 additions and 10 deletions
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2
init/main.c
View file

@ -858,7 +858,7 @@ static int __init kernel_init(void * unused)
/*
* init can allocate pages on any node
*/
set_mems_allowed(node_possible_map);
set_mems_allowed(node_states[N_HIGH_MEMORY]);
/*
* init can run on any cpu.
*/

20
kernel/cpuset.c
View file

@ -920,9 +920,6 @@ 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
@ -1391,11 +1388,10 @@ 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);
@ -2090,15 +2086,23 @@ 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;

2
kernel/kthread.c
View file

@ -219,7 +219,7 @@ 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;