diff options
| -rw-r--r-- | include/linux/cgroup.h | 4 | ||||
| -rw-r--r-- | kernel/cpuset.c | 141 |
2 files changed, 114 insertions, 31 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index d0ad3794b94..53e81a61be5 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -277,6 +277,10 @@ enum { * * - Remount is disallowed. * + * - cpuset: tasks will be kept in empty cpusets when hotplug happens + * and take masks of ancestors with non-empty cpus/mems, instead of + * being moved to an ancestor. + * * - memcg: use_hierarchy is on by default and the cgroup file for * the flag is not created. * diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 82ac1f862cb..3473dd2580d 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -874,6 +874,45 @@ static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap) cgroup_scan_tasks(&scan); } +/* + * update_tasks_cpumask_hier - Update the cpumasks of tasks in the hierarchy. + * @root_cs: the root cpuset of the hierarchy + * @update_root: update root cpuset or not? + * @heap: the heap used by cgroup_scan_tasks() + * + * This will update cpumasks of tasks in @root_cs and all other empty cpusets + * which take on cpumask of @root_cs. + * + * Called with cpuset_mutex held + */ +static void update_tasks_cpumask_hier(struct cpuset *root_cs, + bool update_root, struct ptr_heap *heap) +{ + struct cpuset *cp; + struct cgroup *pos_cgrp; + + if (update_root) + update_tasks_cpumask(root_cs, heap); + + rcu_read_lock(); + cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) { + /* skip the whole subtree if @cp have some CPU */ + if (!cpumask_empty(cp->cpus_allowed)) { + pos_cgrp = cgroup_rightmost_descendant(pos_cgrp); + continue; + } + if (!css_tryget(&cp->css)) + continue; + rcu_read_unlock(); + + update_tasks_cpumask(cp, heap); + + rcu_read_lock(); + css_put(&cp->css); + } + rcu_read_unlock(); +} + /** * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it * @cs: the cpuset to consider @@ -925,11 +964,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); mutex_unlock(&callback_mutex); - /* - * Scan tasks in the cpuset, and update the cpumasks of any - * that need an update. - */ - update_tasks_cpumask(cs, &heap); + update_tasks_cpumask_hier(cs, true, &heap); heap_free(&heap); @@ -1097,6 +1132,45 @@ static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap) } /* + * update_tasks_nodemask_hier - Update the nodemasks of tasks in the hierarchy. + * @cs: the root cpuset of the hierarchy + * @update_root: update the root cpuset or not? + * @heap: the heap used by cgroup_scan_tasks() + * + * This will update nodemasks of tasks in @root_cs and all other empty cpusets + * which take on nodemask of @root_cs. + * + * Called with cpuset_mutex held + */ +static void update_tasks_nodemask_hier(struct cpuset *root_cs, + bool update_root, struct ptr_heap *heap) +{ + struct cpuset *cp; + struct cgroup *pos_cgrp; + + if (update_root) + update_tasks_nodemask(root_cs, heap); + + rcu_read_lock(); + cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) { + /* skip the whole subtree if @cp have some CPU */ + if (!nodes_empty(cp->mems_allowed)) { + pos_cgrp = cgroup_rightmost_descendant(pos_cgrp); + continue; + } + if (!css_tryget(&cp->css)) + continue; + rcu_read_unlock(); + + update_tasks_nodemask(cp, heap); + + rcu_read_lock(); + css_put(&cp->css); + } + rcu_read_unlock(); +} + +/* * Handle user request to change the 'mems' memory placement * of a cpuset. Needs to validate the request, update the * cpusets mems_allowed, and for each task in the cpuset, @@ -1160,7 +1234,7 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, cs->mems_allowed = trialcs->mems_allowed; mutex_unlock(&callback_mutex); - update_tasks_nodemask(cs, &heap); + update_tasks_nodemask_hier(cs, true, &heap); heap_free(&heap); done: @@ -2048,6 +2122,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs) static cpumask_t off_cpus; static nodemask_t off_mems; bool is_empty; + bool sane = cgroup_sane_behavior(cs->css.cgroup); retry: wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); @@ -2066,21 +2141,29 @@ retry: cpumask_andnot(&off_cpus, cs->cpus_allowed, top_cpuset.cpus_allowed); nodes_andnot(off_mems, cs->mems_allowed, top_cpuset.mems_allowed); - /* remove offline cpus from @cs */ - if (!cpumask_empty(&off_cpus)) { - mutex_lock(&callback_mutex); - cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus); - mutex_unlock(&callback_mutex); + mutex_lock(&callback_mutex); + cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus); + mutex_unlock(&callback_mutex); + + /* + * If sane_behavior flag is set, we need to update tasks' cpumask + * for empty cpuset to take on ancestor's cpumask. + */ + if ((sane && cpumask_empty(cs->cpus_allowed)) || + !cpumask_empty(&off_cpus)) update_tasks_cpumask(cs, NULL); - } - /* remove offline mems from @cs */ - if (!nodes_empty(off_mems)) { - mutex_lock(&callback_mutex); - nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems); - mutex_unlock(&callback_mutex); + mutex_lock(&callback_mutex); + nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems); + mutex_unlock(&callback_mutex); + + /* + * If sane_behavior flag is set, we need to update tasks' nodemask + * for empty cpuset to take on ancestor's nodemask. + */ + if ((sane && nodes_empty(cs->mems_allowed)) || + !nodes_empty(off_mems)) update_tasks_nodemask(cs, NULL); - } is_empty = cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed); @@ -2088,11 +2171,13 @@ retry: mutex_unlock(&cpuset_mutex); /* - * If @cs became empty, move tasks to the nearest ancestor with - * execution resources. This is full cgroup operation which will + * If sane_behavior flag is set, we'll keep tasks in empty cpusets. + * + * Otherwise move tasks to the nearest ancestor with execution + * resources. This is full cgroup operation which will * also call back into cpuset. Should be done outside any lock. */ - if (is_empty) + if (!sane && is_empty) remove_tasks_in_empty_cpuset(cs); } @@ -2114,10 +2199,9 @@ retry: */ static void cpuset_hotplug_workfn(struct work_struct *work) { - static cpumask_t new_cpus, tmp_cpus; - static nodemask_t new_mems, tmp_mems; + static cpumask_t new_cpus; + static nodemask_t new_mems; bool cpus_updated, mems_updated; - bool cpus_offlined, mems_offlined; mutex_lock(&cpuset_mutex); @@ -2126,12 +2210,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) new_mems = node_states[N_MEMORY]; cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus); - cpus_offlined = cpumask_andnot(&tmp_cpus, top_cpuset.cpus_allowed, - &new_cpus); - mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems); - nodes_andnot(tmp_mems, top_cpuset.mems_allowed, new_mems); - mems_offlined = !nodes_empty(tmp_mems); /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { @@ -2151,8 +2230,8 @@ static void cpuset_hotplug_workfn(struct work_struct *work) mutex_unlock(&cpuset_mutex); - /* if cpus or mems went down, we need to propagate to descendants */ - if (cpus_offlined || mems_offlined) { + /* if cpus or mems changed, we need to propagate to descendants */ + if (cpus_updated || mems_updated) { struct cpuset *cs; struct cgroup *pos_cgrp; |