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Message-ID: <tip-35fdd6e4bf0868ed9b1d8662fc9fca766d6963d1@git.kernel.org>
Date: Mon, 8 Feb 2016 02:50:31 -0800
From: tip-bot for Thomas Gleixner <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: cmetcalf@...hip.com, linux-kernel@...r.kernel.org,
fweisbec@...il.com, cl@...ux.com, peterz@...radead.org,
hpa@...or.com, tglx@...utronix.de, riel@...hat.com,
bigeasy@...utronix.de, mingo@...nel.org
Subject: [tip:irq/core] genirq:
Add default affinity mask command line option
Commit-ID: 35fdd6e4bf0868ed9b1d8662fc9fca766d6963d1
Gitweb: http://git.kernel.org/tip/35fdd6e4bf0868ed9b1d8662fc9fca766d6963d1
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Wed, 3 Feb 2016 19:52:23 +0100
Committer: Thomas Gleixner <tglx@...utronix.de>
CommitDate: Mon, 8 Feb 2016 11:45:22 +0100
genirq: Add default affinity mask command line option
If we isolate CPUs, then we don't want random device interrupts on them. Even
w/o the user space irq balancer enabled we can end up with irqs on non boot
cpus and chasing newly requested interrupts is a tedious task.
Allow to restrict the default irq affinity mask.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Rik van Riel <riel@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Chris Metcalf <cmetcalf@...hip.com>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Sebastian Siewior <bigeasy@...utronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1602031948190.25254@nanos
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
Documentation/kernel-parameters.txt | 9 +++++++++
kernel/irq/irqdesc.c | 21 +++++++++++++++++++--
2 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 551ecf0..87298f8 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1687,6 +1687,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
ip= [IP_PNP]
See Documentation/filesystems/nfs/nfsroot.txt.
+ irqaffinity= [SMP] Set the default irq affinity mask
+ Format:
+ <cpu number>,...,<cpu number>
+ or
+ <cpu number>-<cpu number>
+ (must be a positive range in ascending order)
+ or a mixture
+ <cpu number>,...,<cpu number>-<cpu number>
+
irqfixup [HW]
When an interrupt is not handled search all handlers
for it. Intended to get systems with badly broken
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 0409da0..0ccd028 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -24,10 +24,27 @@
static struct lock_class_key irq_desc_lock_class;
#if defined(CONFIG_SMP)
+static int __init irq_affinity_setup(char *str)
+{
+ zalloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
+ cpulist_parse(str, irq_default_affinity);
+ /*
+ * Set at least the boot cpu. We don't want to end up with
+ * bugreports caused by random comandline masks
+ */
+ cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
+ return 1;
+}
+__setup("irqaffinity=", irq_affinity_setup);
+
static void __init init_irq_default_affinity(void)
{
- alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
- cpumask_setall(irq_default_affinity);
+#ifdef CONFIG_CPUMASK_OFFSTACK
+ if (!irq_default_affinity)
+ zalloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
+#endif
+ if (cpumask_empty(irq_default_affinity))
+ cpumask_setall(irq_default_affinity);
}
#else
static void __init init_irq_default_affinity(void)
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