lkml.org 
[lkml]   [2010]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[093/156] cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
2.6.33-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Miao Xie <miaox@cn.fujitsu.com>

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>

---
init/main.c | 2 +-
kernel/cpuset.c | 20 ++++++++++++--------
kernel/kthread.c | 2 +-
3 files changed, 14 insertions(+), 10 deletions(-)

--- a/init/main.c
+++ b/init/main.c
@@ -846,7 +846,7 @@ static int __init kernel_init(void * unu
/*
* 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.
*/
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -920,9 +920,6 @@ static int update_cpumask(struct cpuset
* 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_

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(stru
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;
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -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;




\
 
 \ /
  Last update: 2010-03-31 01:39    [W:1.151 / U:0.624 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site