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author | 2014-03-03 17:28:36 -0500 | |
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committer | 2014-03-03 17:28:36 -0500 | |
commit | b8dadcb58d542ecbf1d3dae5fefcd3fd8cb26539 (patch) | |
tree | fc8075d0506b22f79213d97cf4e19408b622454d /kernel | |
parent | cgroup_freezer: document freezer_fork() subtleties (diff) | |
download | linux-b8dadcb58d542ecbf1d3dae5fefcd3fd8cb26539.tar.gz linux-b8dadcb58d542ecbf1d3dae5fefcd3fd8cb26539.tar.bz2 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.c | 24 |
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 |