workqueue: make sysfs of unbound kworker cpumask more clever
[ Upstream commit d25302e46592c97d29f70ccb1be558df31a9a360 ]
Some unfriendly component, such as dpdk, write the same mask to
unbound kworker cpumask again and again. Every time it write to
this interface some work is queue to cpu, even though the mask
is same with the original mask.
So, fix it by return success and do nothing if the cpumask is
equal with the old one.
Signed-off-by: Mengen Sun <mengensun@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4cb622b..d02073b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5326,9 +5326,6 @@
int ret = -EINVAL;
cpumask_var_t saved_cpumask;
- if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL))
- return -ENOMEM;
-
/*
* Not excluding isolated cpus on purpose.
* If the user wishes to include them, we allow that.
@@ -5336,6 +5333,15 @@
cpumask_and(cpumask, cpumask, cpu_possible_mask);
if (!cpumask_empty(cpumask)) {
apply_wqattrs_lock();
+ if (cpumask_equal(cpumask, wq_unbound_cpumask)) {
+ ret = 0;
+ goto out_unlock;
+ }
+
+ if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
/* save the old wq_unbound_cpumask. */
cpumask_copy(saved_cpumask, wq_unbound_cpumask);
@@ -5348,10 +5354,11 @@
if (ret < 0)
cpumask_copy(wq_unbound_cpumask, saved_cpumask);
+ free_cpumask_var(saved_cpumask);
+out_unlock:
apply_wqattrs_unlock();
}
- free_cpumask_var(saved_cpumask);
return ret;
}