From 8d84baf76045f5b9567581cde17e9c3d256bb073 Mon Sep 17 00:00:00 2001
From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Date: Thu, 11 Jul 2024 16:35:41 +0800
Subject: [PATCH] workqueue: Add wq_online_cpumask
The new wq_online_mask mirrors the cpu_online_mask except during
hotplugging; specifically, it differs between the hotplugging stages
of workqueue_offline_cpu() and workqueue_online_cpu(), during which
the transitioning CPU is not represented in the mask.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/workqueue.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4337910cc0348..e49afcb3d90a7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -444,6 +444,9 @@ static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait);
static LIST_HEAD(workqueues); /* PR: list of all workqueues */
static bool workqueue_freezing; /* PL: have wqs started freezing? */
+/* PL: mirror the cpu_online_mask excluding the CPU in the midst of hotplugging */
+static cpumask_var_t wq_online_cpumask;
+
/* PL&A: allowable cpus for unbound wqs and work items */
static cpumask_var_t wq_unbound_cpumask;
@@ -6574,6 +6577,8 @@ int workqueue_online_cpu(unsigned int cpu)
mutex_lock(&wq_pool_mutex);
+ cpumask_set_cpu(cpu, wq_online_cpumask);
+
for_each_pool(pool, pi) {
/* BH pools aren't affected by hotplug */
if (pool->flags & POOL_BH)
@@ -6620,6 +6625,9 @@ int workqueue_offline_cpu(unsigned int cpu)
/* update pod affinity of unbound workqueues */
mutex_lock(&wq_pool_mutex);
+
+ cpumask_clear_cpu(cpu, wq_online_cpumask);
+
list_for_each_entry(wq, &workqueues, list) {
struct workqueue_attrs *attrs = wq->unbound_attrs;
@@ -7649,10 +7657,12 @@ void __init workqueue_init_early(void)
BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
+ BUG_ON(!alloc_cpumask_var(&wq_online_cpumask, GFP_KERNEL));
BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
BUG_ON(!alloc_cpumask_var(&wq_requested_unbound_cpumask, GFP_KERNEL));
BUG_ON(!zalloc_cpumask_var(&wq_isolated_cpumask, GFP_KERNEL));
+ cpumask_copy(wq_online_cpumask, cpu_online_mask);
cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);
restrict_unbound_cpumask("HK_TYPE_WQ", housekeeping_cpumask(HK_TYPE_WQ));
restrict_unbound_cpumask("HK_TYPE_DOMAIN", housekeeping_cpumask(HK_TYPE_DOMAIN));
--
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