The patch titled
cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
has been added to the -mm tree. Its filename is
cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node.patch
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------------------------------------------------------
Subject: cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
From: Miao Xie <miaox@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Reported-by: Nick Piggin <npiggin@xxxxxxx>
Tested-by: Nick Piggin <npiggin@xxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/main.c | 2 +-
kernel/cpuset.c | 20 ++++++++++++--------
kernel/kthread.c | 2 +-
3 files changed, 14 insertions(+), 10 deletions(-)
diff -puN init/main.c~cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node init/main.c
--- a/init/main.c~cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node
+++ a/init/main.c
@@ -860,7 +860,7 @@ 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.
*/
diff -puN kernel/cpuset.c~cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node kernel/cpuset.c
--- a/kernel/cpuset.c~cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node
+++ a/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;
diff -puN kernel/kthread.c~cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node kernel/kthread.c
--- a/kernel/kthread.c~cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node
+++ a/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;
_
Patches currently in -mm which might be from miaox@xxxxxxxxxxxxxx are
origin.patch
cpuset-fix-the-problem-that-cpuset_mem_spread_node-returns-an-offline-node.patch
cpuset-alloc-nodemask_t-on-the-heap-rather-than-the-stack.patch
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