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Date: Fri, 11 Oct 2013 17:51:18 +0800
From: Li Zefan <lizefan@...wei.com>
To: Tejun Heo <tj@...nel.org>
CC: LKML <linux-kernel@...r.kernel.org>,
cgroups <cgroups@...r.kernel.org>
Subject: [PATCH v2 08/12] 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 <lizefan@...wei.com>
---
kernel/cpuset.c | 51 ++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 40 insertions(+), 11 deletions(-)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 040ec59..e47115e 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -82,6 +82,26 @@ struct cpuset {
unsigned long flags; /* "unsigned long" so bitops work */
+ /*
+ * If sane_behavior is set:
+ *
+ * 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.
+ *
+ *
+ * If sane_behavior is not set:
+ *
+ * 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;
@@ -455,9 +475,13 @@ 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;
/*
@@ -779,7 +803,7 @@ 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.effective_cpus, cpu_active_mask))
goto out;
/* Generate domain masks and attrs */
@@ -2191,11 +2215,12 @@ 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->effective_cpus, top_cpuset.effective_cpus);
+ nodes_andnot(off_mems, cs->effective_mems, top_cpuset.effective_mems);
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);
/* Inherit the effective mask of the parent, if it becomes empty. */
cpumask_andnot(cs->effective_cpus, cs->effective_cpus, &off_cpus);
@@ -2214,7 +2239,8 @@ 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);
/* Inherit the effective mask of the parent, if it becomes empty */
nodes_andnot(cs->effective_mems, cs->effective_mems, off_mems);
@@ -2269,6 +2295,7 @@ 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);
@@ -2276,13 +2303,14 @@ 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 (!sane)
+ 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 */
@@ -2291,7 +2319,8 @@ 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.effective_mems = new_mems;
mutex_unlock(&callback_mutex);
update_tasks_nodemask(&top_cpuset, NULL);
--
1.8.0.2
--
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