Commit 5d8ba82c authored Jul 09, 2014 by Li Zefan Committed by Tejun Heo Jul 09, 2014

cpuset: allow writing offlined masks to cpuset.cpus/mems



As the configured masks won't be limited by its parent, and the top
cpuset's masks won't change when hotplug happens, it's natural to
allow writing offlined masks to the configured masks.

If on default hierarchy:

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

If on legacy hierarchy:

	# echo 0 > /sys/devices/system/cpu/cpu1/online
	# mkdir /cpuset/sub
	# echo 1 > /cpuset/sub/cpuset.cpus
	-bash: echo: write error: Invalid argument

Note the checks don't need to be gated by cgroup_on_dfl, because we've
initialized top_cpuset.{cpus,mems}_allowed accordingly in cpuset_bind().

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent be4c9dd7

kernel/cpuset.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -929,7 +929,8 @@ static int update_cpumask(struct cpuset cs, struct cpuset trialcs,
		if (retval < 0)
		return retval;

		if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask))
		if (!cpumask_subset(trialcs->cpus_allowed,
		top_cpuset.cpus_allowed))
		return -EINVAL;
		}

		@@ -1186,7 +1187,7 @@ static int update_nodemask(struct cpuset cs, struct cpuset trialcs,
		goto done;

		if (!nodes_subset(trialcs->mems_allowed,
		node_states[N_MEMORY])) {
		top_cpuset.mems_allowed)) {
		retval = -EINVAL;
		goto done;
		}