[PATCH, resend #2] x86: eliminate pointless adjustment attempts in fixup_irqs()

[PATCH, resend #2] x86: eliminate pointless adjustment attempts in fixup_irqs()

[Jan Beulich]

Not only when an IRQ's affinity equals cpu_online_mask is there no
need to actually try to adjust the affinity, but also when it's a
subset thereof. This particularly avoids adjustment attempts during
system shutdown to any IRQs bound to CPU#0.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

---
 arch/x86/kernel/irq.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 2.6.38-rc5/arch/x86/kernel/irq.c
+++ 2.6.38-rc5-x86-reduce-fixup-irqs/arch/x86/kernel/irq.c
@@ -310,7 +310,7 @@ void fixup_irqs(void)
 		data = &desc->irq_data;
 		affinity = data->affinity;
 		if (!irq_has_action(irq) ||
-		    cpumask_equal(affinity, cpu_online_mask)) {
+		    cpumask_subset(affinity, cpu_online_mask)) {
 			raw_spin_unlock(&desc->lock);
 			continue;
 		}

[tip:x86/irq] x86: Eliminate pointless adjustment attempts in fixup_irqs()

[tip-bot for Jan Beulich]

Commit-ID:  58bff947e2d164c7e5cbf7f485e4b3d4884befeb
Gitweb:     http://git.kernel.org/tip/58bff947e2d164c7e5cbf7f485e4b3d4884befeb
Author:     Jan Beulich <JBeulich@novell.com>
AuthorDate: Thu, 17 Feb 2011 15:54:26 +0000
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 18 Feb 2011 08:58:00 +0100

x86: Eliminate pointless adjustment attempts in fixup_irqs()

Not only when an IRQ's affinity equals cpu_online_mask is there
no need to actually try to adjust the affinity, but also when
it's a subset thereof. This particularly avoids adjustment
attempts during system shutdown to any IRQs bound to CPU#0.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Gary Hade <garyhade@us.ibm.com>
LKML-Reference: <4D5D52C2020000780003272C@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/irq.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 387b6a0..78793ef 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -310,7 +310,7 @@ void fixup_irqs(void)
 		data = &desc->irq_data;
 		affinity = data->affinity;
 		if (!irq_has_action(irq) ||
-		    cpumask_equal(affinity, cpu_online_mask)) {
+		    cpumask_subset(affinity, cpu_online_mask)) {
 			raw_spin_unlock(&desc->lock);
 			continue;
 		}