From ab816ffa09d5cf2bc4f1d96dccea12fa4836d2ca Mon Sep 17 00:00:00 2001
From: Menglong Dong <imagedong@tencent.com>
Date: Sun, 17 Oct 2021 20:04:02 +0800
Subject: [PATCH] workqueue: make sysfs of unbound kworker cpumask more clever
Git-commit: d25302e46592c97d29f70ccb1be558df31a9a360
Patch-mainline: v5.16-rc1
References: stable-5.14.19
[ 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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
kernel/workqueue.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 542c2d03dab6..ccad28bf21e2 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5340,9 +5340,6 @@ 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.
@@ -5350,6 +5347,15 @@ 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);
@@ -5362,10 +5368,11 @@ 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;
}
--
2.26.2