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);
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