PCI: Restrict probe functions to housekeeping CPUs (69a18b18) · Commits · 戴 / test

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

drivers/pci/pci-driver.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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);

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