[PATCH v2 3/4] sched/isolation: Add HK_TYPE_WQ to isolcpus=domain

[Leonardo Bras]

Housekeeping code keeps multiple cpumasks in order to keep track of which
cpus can perform given housekeeping category.

Every time the HK_TYPE_WQ cpumask is checked before queueing work at a cpu
WQ it also happens to check for HK_TYPE_DOMAIN. So It can be assumed that
the Domain isolation also ends up isolating work queues.

Delegating current HK_TYPE_DOMAIN's work queue isolation to HK_TYPE_WQ
makes it simpler to check if a cpu can run a task into an work queue, since
code just need to go through a single HK_TYPE_* cpumask.

Make isolcpus=domain aggregate both HK_TYPE_DOMAIN and HK_TYPE_WQ, and
remove a lot of cpumask_and calls.

Also, remove a unnecessary '|=' at housekeeping_isolcpus_setup() since we
are sure that 'flags == 0' here.

Signed-off-by: Leonardo Bras <leobras@xxxxxxxxxx>
---
 drivers/pci/pci-driver.c | 13 +------------
 kernel/sched/isolation.c |  4 ++--
 kernel/workqueue.c       |  1 -
 net/core/net-sysfs.c     |  1 -
 4 files changed, 3 insertions(+), 16 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 107d77f3c8467..550bef2504b8d 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -371,19 +371,8 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
 	    pci_physfn_is_probed(dev)) {
 		cpu = nr_cpu_ids;
 	} else {
-		cpumask_var_t wq_domain_mask;
-
-		if (!zalloc_cpumask_var(&wq_domain_mask, GFP_KERNEL)) {
-			error = -ENOMEM;
-			goto out;
-		}
-		cpumask_and(wq_domain_mask,
-			    housekeeping_cpumask(HK_TYPE_WQ),
-			    housekeeping_cpumask(HK_TYPE_DOMAIN));
-
 		cpu = cpumask_any_and(cpumask_of_node(node),
-				      wq_domain_mask);
-		free_cpumask_var(wq_domain_mask);
+				      housekeeping_cpumask(HK_TYPE_WQ));
 	}
 
 	if (cpu < nr_cpu_ids)
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 373d42c707bc5..ced4b78564810 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -204,7 +204,7 @@ static int __init housekeeping_isolcpus_setup(char *str)
 
 		if (!strncmp(str, "domain,", 7)) {
 			str += 7;
-			flags |= HK_FLAG_DOMAIN;
+			flags |= HK_FLAG_DOMAIN | HK_FLAG_WQ;
 			continue;
 		}
 
@@ -234,7 +234,7 @@ static int __init housekeeping_isolcpus_setup(char *str)
 
 	/* Default behaviour for isolcpus without flags */
 	if (!flags)
-		flags |= HK_FLAG_DOMAIN;
+		flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
 
 	return housekeeping_setup(str, flags);
 }
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 7cd5f5e7e0a1b..b557daa571f17 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -6004,7 +6004,6 @@ void __init workqueue_init_early(void)
 
 	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
 	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ));
-	cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN));
 
 	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
 
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 8409d41405dfe..7b6fb62a118ab 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -852,7 +852,6 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
 	}
 
 	if (!cpumask_empty(mask)) {
-		cpumask_and(mask, mask, housekeeping_cpumask(HK_TYPE_DOMAIN));
 		cpumask_and(mask, mask, housekeeping_cpumask(HK_TYPE_WQ));
 		if (cpumask_empty(mask)) {
 			free_cpumask_var(mask);
-- 
2.38.0