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cpuset: update cpuset->effective_{cpus,mems} at hotplug

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We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

To make cs->effective_{cpus,mems} to be effective masks, we need to
  - update the effective masks at hotplug
  - update the effective masks at config change
  - take on ancestor's mask when the effective mask is empty

The first item is done here.

This won't introduce behavior change.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2014-07-09 16:47:16 +08:00 committed by Tejun Heo
parent e2b9a3d7d8
commit 1344ab9c29
1 changed files with 4 additions and 0 deletions
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4
kernel/cpuset.c
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@ -2082,6 +2082,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs)
mutex_lock(&callback_mutex);
cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus);
cpumask_andnot(cs->effective_cpus, cs->effective_cpus, &off_cpus);
mutex_unlock(&callback_mutex);
/*
@ -2096,6 +2097,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs)
mutex_lock(&callback_mutex);
nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems);
nodes_andnot(cs->effective_mems, cs->effective_mems, off_mems);
mutex_unlock(&callback_mutex);
/*
@ -2159,6 +2161,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
if (cpus_updated) {
mutex_lock(&callback_mutex);
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 */
}
@ -2167,6 +2170,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
if (mems_updated) {
mutex_lock(&callback_mutex);
top_cpuset.mems_allowed = new_mems;
top_cpuset.effective_mems = new_mems;
mutex_unlock(&callback_mutex);
update_tasks_nodemask(&top_cpuset);
}