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cpuset: enable onlined cpu/node in effective masks

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Firstly offline cpu1:

  # echo 0-1 > cpuset.cpus
  # echo 0 > /sys/devices/system/cpu/cpu1/online
  # cat cpuset.cpus
  0-1
  # cat cpuset.effective_cpus
  0

Then online it:

  # echo 1 > /sys/devices/system/cpu/cpu1/online
  # cat cpuset.cpus
  0-1
  # cat cpuset.effective_cpus
  0-1

And cpuset will bring it back to the effective mask.

The implementation is quite straightforward. Instead of calculating the
offlined cpus/mems and do updates, we just set the new effective_mask
to online_mask & congifured_mask.

This is a behavior change for default hierarchy, so legacy hierarchy
won't be affected.

v2:
- make refactoring of cpuset_hotplug_update_tasks() as seperate patch,
  suggested by Tejun.
- make hotplug_update_tasks_insane() use @new_cpus and @new_mems as
  hotplug_update_tasks_sane() does.

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 16:49:04 +08:00 committed by Tejun Heo
parent 390a36aadf
commit be4c9dd7ae
1 changed files with 36 additions and 29 deletions
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65
kernel/cpuset.c
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@ -2080,26 +2080,27 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
}
}
static void hotplug_update_tasks_legacy(struct cpuset *cs,
struct cpumask *off_cpus,
nodemask_t *off_mems)
static void
hotplug_update_tasks_legacy(struct cpuset *cs,
struct cpumask *new_cpus, nodemask_t *new_mems,
bool cpus_updated, bool mems_updated)
{
bool is_empty;
mutex_lock(&callback_mutex);
cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, off_cpus);
cpumask_andnot(cs->effective_cpus, cs->effective_cpus, off_cpus);
nodes_andnot(cs->mems_allowed, cs->mems_allowed, *off_mems);
nodes_andnot(cs->effective_mems, cs->effective_mems, *off_mems);
cpumask_copy(cs->cpus_allowed, new_cpus);
cpumask_copy(cs->effective_cpus, new_cpus);
cs->mems_allowed = *new_mems;
cs->effective_mems = *new_mems;
mutex_unlock(&callback_mutex);
/*
* Don't call update_tasks_cpumask() if the cpuset becomes empty,
* as the tasks will be migratecd to an ancestor.
*/
if (!cpumask_empty(off_cpus) && !cpumask_empty(cs->cpus_allowed))
if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
update_tasks_cpumask(cs);
if (!nodes_empty(*off_mems) && !nodes_empty(cs->mems_allowed))
if (mems_updated && !nodes_empty(cs->mems_allowed))
update_tasks_nodemask(cs);
is_empty = cpumask_empty(cs->cpus_allowed) ||
@ -2118,24 +2119,24 @@ static void hotplug_update_tasks_legacy(struct cpuset *cs,
mutex_lock(&cpuset_mutex);
}
static void hotplug_update_tasks(struct cpuset *cs,
struct cpumask *off_cpus,
nodemask_t *off_mems)
static void
hotplug_update_tasks(struct cpuset *cs,
struct cpumask *new_cpus, nodemask_t *new_mems,
bool cpus_updated, bool mems_updated)
{
mutex_lock(&callback_mutex);
cpumask_andnot(cs->effective_cpus, cs->effective_cpus, off_cpus);
if (cpumask_empty(cs->effective_cpus))
cpumask_copy(cs->effective_cpus,
parent_cs(cs)->effective_cpus);
if (cpumask_empty(new_cpus))
cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
if (nodes_empty(*new_mems))
*new_mems = parent_cs(cs)->effective_mems;
nodes_andnot(cs->effective_mems, cs->effective_mems, *off_mems);
if (nodes_empty(cs->effective_mems))
cs->effective_mems = parent_cs(cs)->effective_mems;
mutex_lock(&callback_mutex);
cpumask_copy(cs->effective_cpus, new_cpus);
cs->effective_mems = *new_mems;
mutex_unlock(&callback_mutex);
if (!cpumask_empty(off_cpus))
if (cpus_updated)
update_tasks_cpumask(cs);
if (!nodes_empty(*off_mems))
if (mems_updated)
update_tasks_nodemask(cs);
}
@ -2149,8 +2150,10 @@ static void hotplug_update_tasks(struct cpuset *cs,
*/
static void cpuset_hotplug_update_tasks(struct cpuset *cs)
{
static cpumask_t off_cpus;
static nodemask_t off_mems;
static cpumask_t new_cpus;
static nodemask_t new_mems;
bool cpus_updated;
bool mems_updated;
retry:
wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
@ -2165,14 +2168,18 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs)
goto retry;
}
cpumask_andnot(&off_cpus, cs->effective_cpus,
top_cpuset.effective_cpus);
nodes_andnot(off_mems, cs->effective_mems, top_cpuset.effective_mems);
cpumask_and(&new_cpus, cs->cpus_allowed, parent_cs(cs)->effective_cpus);
nodes_and(new_mems, cs->mems_allowed, parent_cs(cs)->effective_mems);
cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
mems_updated = !nodes_equal(new_mems, cs->effective_mems);
if (cgroup_on_dfl(cs->css.cgroup))
hotplug_update_tasks(cs, &off_cpus, &off_mems);
hotplug_update_tasks(cs, &new_cpus, &new_mems,
cpus_updated, mems_updated);
else
hotplug_update_tasks_legacy(cs, &off_cpus, &off_mems);
hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
cpus_updated, mems_updated);
mutex_unlock(&cpuset_mutex);
}