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From: Nitesh Narayan Lal <nitesh@redhat.com>
To: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	frederic@kernel.org, mtosatti@redhat.com, juri.lelli@redhat.com,
	abelits@marvell.com, bhelgaas@google.com,
	linux-pci@vger.kernel.org, rostedt@goodmis.org, mingo@kernel.org,
	peterz@infradead.org, tglx@linutronix.de, davem@davemloft.net,
	akpm@linux-foundation.org, sfr@canb.auug.org.au,
	stephen@networkplumber.org, rppt@linux.vnet.ibm.com,
	jinyuqi@huawei.com, zhangshaokun@hisilicon.com
Subject: [Patch v4 2/3] PCI: Restrict probe functions to housekeeping CPUs
Date: Thu, 25 Jun 2020 18:34:42 -0400
Message-ID: <20200625223443.2684-3-nitesh@redhat.com> (raw)
In-Reply-To: <20200625223443.2684-1-nitesh@redhat.com>

From: Alex Belits <abelits@marvell.com>

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>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
---
 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


  parent reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-25 22:34 [PATCH v4 0/3] Preventing job distribution to isolated CPUs Nitesh Narayan Lal
2020-06-25 22:34 ` [Patch v4 1/3] lib: Restrict cpumask_local_spread to houskeeping CPUs Nitesh Narayan Lal
2020-06-29 16:11   ` Nitesh Narayan Lal
2020-07-01  0:32     ` Andrew Morton
2020-07-01  0:47       ` Nitesh Narayan Lal
2020-06-25 22:34 ` Nitesh Narayan Lal [this message]
2020-06-25 22:34 ` [Patch v4 3/3] net: Restrict receive packets queuing to housekeeping CPUs Nitesh Narayan Lal
2020-06-26 11:14   ` Peter Zijlstra
2020-06-26 17:20     ` David Miller

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