From: Menglong Dong imagedong@tencent.com
[ 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 --- kernel/workqueue.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1b3eb1e9531f4..76988f39ed5ac 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5384,9 +5384,6 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) 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. @@ -5394,6 +5391,15 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) 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); @@ -5406,10 +5412,11 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) 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; }