From 7e88291beefbb758fa3b27e500ee2e0c888d6e44 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 9 Jul 2014 16:48:42 +0800 Subject: [PATCH] cpuset: make cs->{cpus, mems}_allowed as user-configured masks Now we've used effective cpumasks to enforce hierarchical manner, we can use cs->{cpus,mems}_allowed as configured masks. Configured masks can be changed by writing cpuset.cpus and cpuset.mems only. The new behaviors are: - They won't be changed by hotplug anymore. - They won't be limited by its parent's masks. This ia a behavior change, but won't take effect unless mount with sane_behavior. v2: - Add comments to explain the differences between configured masks and effective masks. Signed-off-by: Li Zefan Signed-off-by: Tejun Heo --- kernel/cpuset.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 820870a715f8..4b409d2ecbb9 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -77,6 +77,26 @@ struct cpuset { unsigned long flags; /* "unsigned long" so bitops work */ + /* + * On default hierarchy: + * + * The user-configured masks can only be changed by writing to + * cpuset.cpus and cpuset.mems, and won't be limited by the + * parent masks. + * + * The effective masks is the real masks that apply to the tasks + * in the cpuset. They may be changed if the configured masks are + * changed or hotplug happens. + * + * effective_mask == configured_mask & parent's effective_mask, + * and if it ends up empty, it will inherit the parent's mask. + * + * + * On legacy hierachy: + * + * The user-configured masks are always the same with effective masks. + */ + /* user-configured CPUs and Memory Nodes allow to tasks */ cpumask_var_t cpus_allowed; nodemask_t mems_allowed; @@ -450,9 +470,9 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) par = parent_cs(cur); - /* We must be a subset of our parent cpuset */ + /* On legacy hiearchy, we must be a subset of our parent cpuset. */ ret = -EACCES; - if (!is_cpuset_subset(trial, par)) + if (!cgroup_on_dfl(cur->css.cgroup) && !is_cpuset_subset(trial, par)) goto out; /* @@ -2167,6 +2187,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) static cpumask_t new_cpus; static nodemask_t new_mems; bool cpus_updated, mems_updated; + bool on_dfl = cgroup_on_dfl(top_cpuset.css.cgroup); mutex_lock(&cpuset_mutex); @@ -2174,13 +2195,14 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpumask_copy(&new_cpus, cpu_active_mask); new_mems = node_states[N_MEMORY]; - cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus); - mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems); + cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); + mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { mutex_lock(&callback_mutex); - cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); + if (!on_dfl) + cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); cpumask_copy(top_cpuset.effective_cpus, &new_cpus); mutex_unlock(&callback_mutex); /* we don't mess with cpumasks of tasks in top_cpuset */ @@ -2189,7 +2211,8 @@ static void cpuset_hotplug_workfn(struct work_struct *work) /* synchronize mems_allowed to N_MEMORY */ if (mems_updated) { mutex_lock(&callback_mutex); - top_cpuset.mems_allowed = new_mems; + if (!on_dfl) + top_cpuset.mems_allowed = new_mems; top_cpuset.effective_mems = new_mems; mutex_unlock(&callback_mutex); update_tasks_nodemask(&top_cpuset); -- 2.30.2