On 6/16/20 4:05 PM, Bjorn Helgaas wrote:

"git log --oneline drivers/pci/pci-driver.c" tells you that the
subject should be something like:

  PCI: Restrict probe functions to housekeeping CPUs

On Wed, Jun 10, 2020 at 12:12:25PM -0400, Nitesh Narayan Lal wrote:

quoted

From: Alex Belits <redacted>

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 Physical device.
This patch replaces 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.

s/Physical/PF/ (since you used "VF" earlier, this should match that)

s/This patch replaces/Replace the/

Please rewrap this to fill a 75 column line (so it doesn't overflow 80
columns when "git log" adds 4 spaces).

This should be two paragraphs; add a blank line between them.

Thanks for pointing these out.
I will correct it in the next posting before that I will wait for any comments
on other patches.

quoted

Signed-off-by: Alex Belits <redacted>
Signed-off-by: Nitesh Narayan Lal <redacted>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

quoted

---
 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 da6510af1221..449466f71040 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);

-- 
2.18.4

-- 
Nitesh