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authorLi Zefan <lizefan@huawei.com>2014-03-03 23:28:36 +0100
committerTejun Heo <tj@kernel.org>2014-03-03 23:28:36 +0100
commitb8dadcb58d542ecbf1d3dae5fefcd3fd8cb26539 (patch)
treefc8075d0506b22f79213d97cf4e19408b622454d /kernel
parentcgroup_freezer: document freezer_fork() subtleties (diff)
downloadlinux-b8dadcb58d542ecbf1d3dae5fefcd3fd8cb26539.tar.xz
linux-b8dadcb58d542ecbf1d3dae5fefcd3fd8cb26539.zip
cpuset: use rcu_read_lock() to protect task_cs()
We no longer use task_lock() to protect tsk->cgroups. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index d8bec21d7a11..8d5324583aa4 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2239,10 +2239,10 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
struct cpuset *cpus_cs;
mutex_lock(&callback_mutex);
- task_lock(tsk);
+ rcu_read_lock();
cpus_cs = effective_cpumask_cpuset(task_cs(tsk));
guarantee_online_cpus(cpus_cs, pmask);
- task_unlock(tsk);
+ rcu_read_unlock();
mutex_unlock(&callback_mutex);
}
@@ -2295,10 +2295,10 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
nodemask_t mask;
mutex_lock(&callback_mutex);
- task_lock(tsk);
+ rcu_read_lock();
mems_cs = effective_nodemask_cpuset(task_cs(tsk));
guarantee_online_mems(mems_cs, &mask);
- task_unlock(tsk);
+ rcu_read_unlock();
mutex_unlock(&callback_mutex);
return mask;
@@ -2414,9 +2414,9 @@ int __cpuset_node_allowed_softwall(int node, gfp_t gfp_mask)
/* Not hardwall and node outside mems_allowed: scan up cpusets */
mutex_lock(&callback_mutex);
- task_lock(current);
+ rcu_read_lock();
cs = nearest_hardwall_ancestor(task_cs(current));
- task_unlock(current);
+ rcu_read_unlock();
allowed = node_isset(node, cs->mems_allowed);
mutex_unlock(&callback_mutex);
@@ -2543,24 +2543,26 @@ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
* @task: pointer to task_struct of some task.
*
* Description: Prints @task's name, cpuset name, and cached copy of its
- * mems_allowed to the kernel log. Must hold task_lock(task) to allow
- * dereferencing task_cs(task).
+ * mems_allowed to the kernel log.
*/
void cpuset_print_task_mems_allowed(struct task_struct *tsk)
{
/* Statically allocated to prevent using excess stack. */
static char cpuset_nodelist[CPUSET_NODELIST_LEN];
static DEFINE_SPINLOCK(cpuset_buffer_lock);
- struct cgroup *cgrp = task_cs(tsk)->css.cgroup;
+ struct cgroup *cgrp;
spin_lock(&cpuset_buffer_lock);
+ rcu_read_lock();
+ cgrp = task_cs(tsk)->css.cgroup;
nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
tsk->mems_allowed);
printk(KERN_INFO "%s cpuset=", tsk->comm);
pr_cont_cgroup_name(cgrp);
pr_cont(" mems_allowed=%s\n", cpuset_nodelist);
+ rcu_read_unlock();
spin_unlock(&cpuset_buffer_lock);
}
@@ -2592,9 +2594,9 @@ int cpuset_memory_pressure_enabled __read_mostly;
void __cpuset_memory_pressure_bump(void)
{
- task_lock(current);
+ rcu_read_lock();
fmeter_markevent(&task_cs(current)->fmeter);
- task_unlock(current);
+ rcu_read_unlock();
}
#ifdef CONFIG_PROC_PID_CPUSET