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 behavior change won't take effect unless mount with sane_behavior.

Signed-off-by: Li Zefan <[email protected]>
---
 kernel/cpuset.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index e7ad4a7..c3a02a9 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -457,9 +457,13 @@ static int validate_change(struct cpuset *cur, struct 
cpuset *trial)
 
        par = parent_cs(cur);
 
-       /* We must be a subset of our parent cpuset */
+       /*
+        * We must be a subset of our parent cpuset, unless sane_behavior
+        * flag is set.
+        */
        ret = -EACCES;
-       if (!is_cpuset_subset(trial, par))
+       if (!cgroup_sane_behavior(cur->css.cgroup) &&
+           !is_cpuset_subset(trial, par))
                goto out;
 
        /*
@@ -780,7 +784,7 @@ static void rebuild_sched_domains_locked(void)
         * passing doms with offlined cpu to partition_sched_domains().
         * Anyways, hotplug work item will rebuild sched domains.
         */
-       if (!cpumask_equal(top_cpuset.cpus_allowed, cpu_active_mask))
+       if (!cpumask_equal(top_cpuset.real_cpus_allowed, cpu_active_mask))
                goto out;
 
        /* Generate domain masks and attrs */
@@ -2159,11 +2163,14 @@ retry:
                goto retry;
        }
 
-       cpumask_andnot(&off_cpus, cs->cpus_allowed, top_cpuset.cpus_allowed);
-       nodes_andnot(off_mems, cs->mems_allowed, top_cpuset.mems_allowed);
+       cpumask_andnot(&off_cpus, cs->real_cpus_allowed,
+                      top_cpuset.real_cpus_allowed);
+       nodes_andnot(off_mems, cs->real_mems_allowed,
+                    top_cpuset.real_mems_allowed);
 
        mutex_lock(&callback_mutex);
-       cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus);
+       if (!sane)
+               cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus);
 
        cpumask_andnot(cs->real_cpus_allowed, cs->real_cpus_allowed,
                       &off_cpus);
@@ -2184,7 +2191,8 @@ retry:
                update_tasks_cpumask(cs, NULL);
 
        mutex_lock(&callback_mutex);
-       nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems);
+       if (!sane)
+               nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems);
 
        nodes_andnot(cs->real_mems_allowed, cs->real_mems_allowed, off_mems);
        /* Inherite the effective mask of the parent, if it becomes empty */
@@ -2239,6 +2247,7 @@ 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 sane = cgroup_sane_behavior(top_cpuset.css.cgroup);
 
        mutex_lock(&cpuset_mutex);
 
@@ -2246,13 +2255,14 @@ 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.real_cpus_allowed, &new_cpus);
+       mems_updated = !nodes_equal(top_cpuset.real_mems_allowed, 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 (!sane)
+                       cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
                cpumask_copy(top_cpuset.real_cpus_allowed, &new_cpus);
                mutex_unlock(&callback_mutex);
                /* we don't mess with cpumasks of tasks in top_cpuset */
@@ -2261,7 +2271,8 @@ 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 (!sane)
+                       top_cpuset.mems_allowed = new_mems;
                top_cpuset.real_mems_allowed = new_mems;
                mutex_unlock(&callback_mutex);
                update_tasks_nodemask(&top_cpuset, NULL);
-- 
1.8.0.2
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