{
bool need_loop;
-repeat:
/*
* Allow tasks that have access to memory reserves because they have
* been OOM killed to get memory anywhere.
*/
need_loop = task_has_mempolicy(tsk) ||
!nodes_intersects(*newmems, tsk->mems_allowed);
- nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
- mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
-
- /*
- * ensure checking ->mems_allowed_change_disable after setting all new
- * allowed nodes.
- *
- * the read-side task can see an nodemask with new allowed nodes and
- * old allowed nodes. and if it allocates page when cpuset clears newly
- * disallowed ones continuous, it can see the new allowed bits.
- *
- * And if setting all new allowed nodes is after the checking, setting
- * all new allowed nodes and clearing newly disallowed ones will be done
- * continuous, and the read-side task may find no node to alloc page.
- */
- smp_mb();
- /*
- * Allocation of memory is very fast, we needn't sleep when waiting
- * for the read-side.
- */
- while (need_loop && ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
- task_unlock(tsk);
- if (!task_curr(tsk))
- yield();
- goto repeat;
+ if (need_loop) {
+ local_irq_disable();
+ write_seqcount_begin(&tsk->mems_allowed_seq);
}
- /*
- * ensure checking ->mems_allowed_change_disable before clearing all new
- * disallowed nodes.
- *
- * if clearing newly disallowed bits before the checking, the read-side
- * task may find no node to alloc page.
- */
- smp_mb();
+ nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
+ mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2);
tsk->mems_allowed = *newmems;
+
+ if (need_loop) {
+ write_seqcount_end(&tsk->mems_allowed_seq);
+ local_irq_enable();
+ }
+
task_unlock(tsk);
}
* (of no affect) on systems that are actively using CPU hotplug
* but making no active use of cpusets.
*
+ * The only exception to this is suspend/resume, where we don't
+ * modify cpusets at all.
+ *
* This routine ensures that top_cpuset.cpus_allowed tracks
* cpu_active_mask on each CPU hotplug (cpuhp) event.
*
task_lock(current);
cs = nearest_hardwall_ancestor(task_cs(current));
+ allowed = node_isset(node, cs->mems_allowed);
task_unlock(current);
- allowed = node_isset(node, cs->mems_allowed);
mutex_unlock(&callback_mutex);
return allowed;
}
dentry = task_cs(tsk)->css.cgroup->dentry;
spin_lock(&cpuset_buffer_lock);
- snprintf(cpuset_name, CPUSET_NAME_LEN,
- dentry ? (const char *)dentry->d_name.name : "/");
+
+ if (!dentry) {
+ strcpy(cpuset_name, "/");
+ } else {
+ spin_lock(&dentry->d_lock);
+ strlcpy(cpuset_name, (const char *)dentry->d_name.name,
+ CPUSET_NAME_LEN);
+ spin_unlock(&dentry->d_lock);
+ }
+
nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
tsk->mems_allowed);
printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n",