BUG_ON(!nodes_intersects(*pmask, node_online_map));
}
-/*
- * Refresh current tasks mems_allowed and mems_generation from current
- * tasks cpuset.
+/**
+ * cpuset_update_task_memory_state - update task memory placement
+ *
+ * If the current tasks cpusets mems_allowed changed behind our
+ * backs, update current->mems_allowed, mems_generation and task NUMA
+ * mempolicy to the new value.
+ *
+ * Task mempolicy is updated by rebinding it relative to the
+ * current->cpuset if a task has its memory placement changed.
+ * Do not call this routine if in_interrupt().
*
- * Call without callback_sem or task_lock() held. May be called with
- * or without manage_sem held. Will acquire task_lock() and might
- * acquire callback_sem during call.
+ * Call without callback_sem or task_lock() held. May be called
+ * with or without manage_sem held. Except in early boot or
+ * an exiting task, when tsk->cpuset is NULL, this routine will
+ * acquire task_lock(). We don't need to use task_lock to guard
+ * against another task changing a non-NULL cpuset pointer to NULL,
+ * as that is only done by a task on itself, and if the current task
+ * is here, it is not simultaneously in the exit code NULL'ing its
+ * cpuset pointer. This routine also might acquire callback_sem and
+ * current->mm->mmap_sem during call.
*
* The task_lock() is required to dereference current->cpuset safely.
* Without it, we could pick up the pointer value of current->cpuset
* task has been modifying its cpuset.
*/
-static void refresh_mems(void)
+void cpuset_update_task_memory_state()
{
int my_cpusets_mem_gen;
+ struct task_struct *tsk = current;
+ struct cpuset *cs = tsk->cpuset;
- task_lock(current);
- my_cpusets_mem_gen = current->cpuset->mems_generation;
- task_unlock(current);
+ if (unlikely(!cs))
+ return;
- if (current->cpuset_mems_generation != my_cpusets_mem_gen) {
- struct cpuset *cs;
- nodemask_t oldmem = current->mems_allowed;
+ task_lock(tsk);
+ my_cpusets_mem_gen = cs->mems_generation;
+ task_unlock(tsk);
+
+ if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
+ nodemask_t oldmem = tsk->mems_allowed;
int migrate;
down(&callback_sem);
- task_lock(current);
- cs = current->cpuset;
+ task_lock(tsk);
+ cs = tsk->cpuset; /* Maybe changed when task not locked */
migrate = is_memory_migrate(cs);
- guarantee_online_mems(cs, ¤t->mems_allowed);
- current->cpuset_mems_generation = cs->mems_generation;
- task_unlock(current);
+ guarantee_online_mems(cs, &tsk->mems_allowed);
+ tsk->cpuset_mems_generation = cs->mems_generation;
+ task_unlock(tsk);
up(&callback_sem);
- if (!nodes_equal(oldmem, current->mems_allowed)) {
- numa_policy_rebind(&oldmem, ¤t->mems_allowed);
+ mpol_rebind_task(tsk, &tsk->mems_allowed);
+ if (!nodes_equal(oldmem, tsk->mems_allowed)) {
if (migrate) {
- do_migrate_pages(current->mm, &oldmem,
- ¤t->mems_allowed,
+ do_migrate_pages(tsk->mm, &oldmem,
+ &tsk->mems_allowed,
MPOL_MF_MOVE_ALL);
}
}
return -ENOMEM;
down(&manage_sem);
- refresh_mems();
+ cpuset_update_task_memory_state();
cs->flags = 0;
if (notify_on_release(parent))
set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
/* the vfs holds both inode->i_sem already */
down(&manage_sem);
- refresh_mems();
+ cpuset_update_task_memory_state();
if (atomic_read(&cs->count) > 0) {
up(&manage_sem);
return -EBUSY;
*
* We don't need to task_lock() this reference to tsk->cpuset,
* because tsk is already marked PF_EXITING, so attach_task() won't
- * mess with it.
+ * mess with it, or task is a failed fork, never visible to attach_task.
**/
void cpuset_exit(struct task_struct *tsk)
{
struct cpuset *cs;
- BUG_ON(!(tsk->flags & PF_EXITING));
-
cs = tsk->cpuset;
tsk->cpuset = NULL;
* tasks cpuset.
**/
-cpumask_t cpuset_cpus_allowed(const struct task_struct *tsk)
+cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
{
cpumask_t mask;
down(&callback_sem);
- task_lock((struct task_struct *)tsk);
+ task_lock(tsk);
guarantee_online_cpus(tsk->cpuset, &mask);
- task_unlock((struct task_struct *)tsk);
+ task_unlock(tsk);
up(&callback_sem);
return mask;
}
/**
- * cpuset_update_current_mems_allowed - update mems parameters to new values
- *
- * If the current tasks cpusets mems_allowed changed behind our backs,
- * update current->mems_allowed and mems_generation to the new value.
- * Do not call this routine if in_interrupt().
+ * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
+ * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
*
- * Call without callback_sem or task_lock() held. May be called
- * with or without manage_sem held. Unless exiting, it will acquire
- * task_lock(). Also might acquire callback_sem during call to
- * refresh_mems().
- */
+ * Description: Returns the nodemask_t mems_allowed of the cpuset
+ * attached to the specified @tsk. Guaranteed to return some non-empty
+ * subset of node_online_map, even if this means going outside the
+ * tasks cpuset.
+ **/
-void cpuset_update_current_mems_allowed(void)
+nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
{
- struct cpuset *cs;
- int need_to_refresh = 0;
+ nodemask_t mask;
- task_lock(current);
- cs = current->cpuset;
- if (!cs)
- goto done;
- if (current->cpuset_mems_generation != cs->mems_generation)
- need_to_refresh = 1;
-done:
- task_unlock(current);
- if (need_to_refresh)
- refresh_mems();
+ down(&callback_sem);
+ task_lock(tsk);
+ guarantee_online_mems(tsk->cpuset, &mask);
+ task_unlock(tsk);
+ up(&callback_sem);
+
+ return mask;
}
/**
git.openpandora.org / pandora-kernel.git / blobdiff