From 1bccd58bfffc5a677051937b332b71f0686187c1 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Thu, 7 Jun 2012 15:15:15 +0200 Subject: [PATCH] x86/apic: Try to spread IRQ vectors to different priority levels When assigning a new vector it is primarially done by adding 8 to the previously given out vector number. Hence, two consequently allocated vector numbers would likely fall into the same priority level. Try to spread vector numbers to different priority levels better by changing the step from 8 to 16. Signed-off-by: Alexander Gordeev Acked-by: Suresh Siddha Cc: Yinghai Lu Link: http://lkml.kernel.org/r/20120607131514.GD4759@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/io_apic.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 74c569791e75..05af3d341aaa 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1112,7 +1112,7 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) * 0x80, because int 0x80 is hm, kind of importantish. ;) */ static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START; - static int current_offset = VECTOR_OFFSET_START % 8; + static int current_offset = VECTOR_OFFSET_START % 16; unsigned int old_vector; int cpu, err; cpumask_var_t tmp_mask; @@ -1148,10 +1148,9 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) vector = current_vector; offset = current_offset; next: - vector += 8; + vector += 16; if (vector >= first_system_vector) { - /* If out of vectors on large boxen, must share them. */ - offset = (offset + 1) % 8; + offset = (offset + 1) % 16; vector = FIRST_EXTERNAL_VECTOR + offset; } if (unlikely(current_vector == vector)) -- 2.39.5