The following commit has been merged into the sched/core branch of tip:
Commit-ID: 69a18b18699b59654333651d95f8ca09d01048f8
Gitweb: https://git.kernel.org/tip/69a18b18699b59654333651d95f8ca09d01048f8
Author: Alex Belits <abelits@xxxxxxxxxxx>
AuthorDate: Thu, 25 Jun 2020 18:34:42 -04:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 08 Jul 2020 11:39:01 +02:00
PCI: Restrict probe functions to housekeeping CPUs
pci_call_probe() prevents the nesting of work_on_cpu() for a scenario
where a VF device is probed from work_on_cpu() of the PF.
Replace the cpumask used in pci_call_probe() from all online CPUs to only
housekeeping CPUs. This is to ensure that there are no additional latency
overheads caused due to the pinning of jobs on isolated CPUs.
Signed-off-by: Alex Belits <abelits@xxxxxxxxxxx>
Signed-off-by: Nitesh Narayan Lal <nitesh@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200625223443.2684-3-nitesh@xxxxxxxxxx
---
drivers/pci/pci-driver.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index da6510a..449466f 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -12,6 +12,7 @@
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/sched.h>
+#include <linux/sched/isolation.h>
#include <linux/cpu.h>
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
@@ -333,6 +334,7 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
const struct pci_device_id *id)
{
int error, node, cpu;
+ int hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
struct drv_dev_and_id ddi = { drv, dev, id };
/*
@@ -353,7 +355,8 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
pci_physfn_is_probed(dev))
cpu = nr_cpu_ids;
else
- cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
+ cpu = cpumask_any_and(cpumask_of_node(node),
+ housekeeping_cpumask(hk_flags));
if (cpu < nr_cpu_ids)
error = work_on_cpu(cpu, local_pci_probe, &ddi);
|