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PCI: Restrict probe functions to housekeeping CPUs

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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@marvell.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lkml.kernel.org/r/20200625223443.2684-3-nitesh@redhat.com
This commit is contained in:
Alex Belits 2020-06-25 18:34:42 -04:00 committed by Peter Zijlstra
parent 1abdfe706a
commit 69a18b1869
1 changed files with 4 additions and 1 deletions
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5
drivers/pci/pci-driver.c
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@ -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);