Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753860Ab0ADThQ (ORCPT ); Mon, 4 Jan 2010 14:37:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753520Ab0ADThN (ORCPT ); Mon, 4 Jan 2010 14:37:13 -0500 Received: from hera.kernel.org ([140.211.167.34]:36633 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753409Ab0ADThM (ORCPT ); Mon, 4 Jan 2010 14:37:12 -0500 Message-ID: <4B424305.7050803@kernel.org> Date: Mon, 04 Jan 2010 11:35:33 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091130 SUSE/3.0.0-1.1.1 Thunderbird/3.0 MIME-Version: 1.0 To: "Eric W. Biederman" CC: "H. Peter Anvin" , Jesse Brandeburg , Ingo Molnar , Thomas Gleixner , "linux-kernel@vger.kernel.org" , Andrew Morton , NetDEV list , Jesse Brandeburg Subject: Re: Subject: [PATCH 1/2] x86: get back 15 vectors References: <4B347AEE.6030705@kernel.org> <20091228094707.GH24690@elte.hu> <4B398ECD.1080506@kernel.org> <4807377b1001031906s6b1ee576jc021da2642bb4147@mail.gmail.com> <4B415E73.1050801@kernel.org> <4B419113.1090204@kernel.org> <4B423B08.3010005@zytor.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4655 Lines: 129 On 01/04/2010 11:09 AM, Eric W. Biederman wrote: > "H. Peter Anvin" writes: > >> On 01/04/2010 08:18 AM, Eric W. Biederman wrote: >>> Yinghai Lu writes: >>> >>> This patch is wrong. >>> >>>> between FIRST_EXTERNAL_VECTOR (0x20) and FIRST_DEVICE_VECTOR (0x41) >>>> >>>> for 0x20 and 0x2f, we are safe be used_vectors will prevent it to use used one. >>> >>> We can not use any of 0x20 - 0x2f for ioapic irqs. We need the entire >>> priority level to ensure that the irq move cleanup ipi is of a lower >>> priority. >>> >> >> Almost makes one want to abuse 0x1f for that. Although 0x00..0x1f are >> reserved for exceptions, the APICs range down to 0x10, and well, when >> 0x1f ends up actually getting used as an exception vector that we >> support, then we can trivially change that. In the meantime it would >> actually make use of an otherwise-unusable APIC priority level. > > An optimization like that (with a big fat comment) seems reasonable > to me. so we can use [0x10, 0x1f] sth like this? Subject: [PATCH 1/2] x86: get back 16 vectors -v2: according to hpa that we could start from 0x10 according to Eric, we should hold 16 vectors for IRQ MOVE Signed-off-by: Yinghai Lu --- arch/x86/include/asm/irq_vectors.h | 3 ++- arch/x86/kernel/apic/io_apic.c | 5 +++-- arch/x86/kernel/irqinit.c | 11 +++++++++-- 3 files changed, 14 insertions(+), 5 deletions(-) Index: linux-2.6/arch/x86/kernel/apic/io_apic.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c +++ linux-2.6/arch/x86/kernel/apic/io_apic.c @@ -1162,7 +1162,8 @@ __assign_irq_vector(int irq, struct irq_ * Also, we've got to be careful not to trash gate * 0x80, because int 0x80 is hm, kind of importantish. ;) */ - static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0; + static int current_vector = 0; + static int current_offset = 0; unsigned int old_vector; int cpu, err; cpumask_var_t tmp_mask; @@ -1198,7 +1199,7 @@ next: if (vector >= first_system_vector) { /* If out of vectors on large boxen, must share them. */ offset = (offset + 1) % 8; - vector = FIRST_DEVICE_VECTOR + offset; + vector = 0 + offset; } if (unlikely(current_vector == vector)) continue; Index: linux-2.6/arch/x86/include/asm/irq_vectors.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/irq_vectors.h +++ linux-2.6/arch/x86/include/asm/irq_vectors.h @@ -30,8 +30,9 @@ /* * IDT vectors usable for external interrupt sources start * at 0x20: + * hpa said we can start from 0x10 */ -#define FIRST_EXTERNAL_VECTOR 0x20 +#define FIRST_EXTERNAL_VECTOR 0x10 #ifdef CONFIG_X86_32 # define SYSCALL_VECTOR 0x80 Index: linux-2.6/arch/x86/kernel/irqinit.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/irqinit.c +++ linux-2.6/arch/x86/kernel/irqinit.c @@ -149,6 +149,8 @@ static void __init smp_intr_init(void) { #ifdef CONFIG_SMP #if defined(CONFIG_X86_64) || defined(CONFIG_X86_LOCAL_APIC) + int i; + /* * The reschedule interrupt is a CPU-to-CPU reschedule-helper * IPI, driven by wakeup. @@ -174,7 +176,9 @@ static void __init smp_intr_init(void) /* Low priority IPI to cleanup after moving an irq */ set_intr_gate(IRQ_MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt); - set_bit(IRQ_MOVE_CLEANUP_VECTOR, used_vectors); + /* Eric said: Need to hold entire priority */ + for (i = IRQ_MOVE_CLEANUP_VECTOR; i < IRQ_MOVE_CLEANUP_VECTOR+0x10; i++) + set_bit(i, used_vectors); /* IPI used for rebooting/stopping */ alloc_intr_gate(REBOOT_VECTOR, reboot_interrupt); @@ -222,6 +226,9 @@ void __init native_init_IRQ(void) /* Execute any quirks before the call gates are initialised: */ x86_init.irqs.pre_vector_init(); + for (i = 0; i < 0x10; i++) + set_bit(i, used_vectors); + apic_intr_init(); /* @@ -229,7 +236,7 @@ void __init native_init_IRQ(void) * us. (some of these will be overridden and become * 'special' SMP interrupts) */ - for (i = FIRST_EXTERNAL_VECTOR; i < NR_VECTORS; i++) { + for (i = 0; i < NR_VECTORS; i++) { /* IA32_SYSCALL_VECTOR could be used in trap_init already. */ if (!test_bit(i, used_vectors)) set_intr_gate(i, interrupt[i-FIRST_EXTERNAL_VECTOR]); -- 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/