Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759734Ab2FGNP0 (ORCPT ); Thu, 7 Jun 2012 09:15:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1030 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759493Ab2FGNPW (ORCPT ); Thu, 7 Jun 2012 09:15:22 -0400 Date: Thu, 7 Jun 2012 15:15:15 +0200 From: Alexander Gordeev To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Suresh Siddha , Yinghai Lu Subject: [PATCH 5/8] x86/apic: Try to spread IRQ vectors to different priority levels Message-ID: <20120607131514.GD4759@dhcp-26-207.brq.redhat.com> References: <20120605112353.GA11457@dhcp-26-207.brq.redhat.com> <20120606082231.GD5991@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120606082231.GD5991@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1827 Lines: 50 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 --- arch/x86/kernel/apic/io_apic.c | 7 +++---- 1 files changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 74c5697..05af3d3 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)) -- 1.7.7.6 -- Regards, Alexander Gordeev agordeev@redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/