From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031573AbXD3RoD (ORCPT ); Mon, 30 Apr 2007 13:44:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031578AbXD3RoB (ORCPT ); Mon, 30 Apr 2007 13:44:01 -0400 Received: from holomorphy.com ([66.93.40.71]:56427 "EHLO holomorphy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031573AbXD3Rnl (ORCPT ); Mon, 30 Apr 2007 13:43:41 -0400 Date: Mon, 30 Apr 2007 10:44:05 -0700 From: William Lee Irwin III To: Andi Kleen Cc: Christoph Hellwig , Alan Cox , David Chinner , Zan Lynx , Adrian Bunk , Linux Kernel Subject: [3/6] make IRQ stacks independently configurable (was: Re: [-mm patch] i386: enable 4k stacks by default) Message-ID: <20070430174405.GF19966@holomorphy.com> References: <20070428191927.GN3468@stusta.de> <1177795118.7828.6.camel@localhost> <20070430035838.GC77450368@melbourne.sgi.com> <20070430091754.24df88df@the-village.bc.nu> <20070430104806.GA14944@infradead.org> <20070430173819.GC19966@holomorphy.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070430173819.GC19966@holomorphy.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 30, 2007 at 10:38:19AM -0700, William Lee Irwin III wrote: > Here's what I did for i386 for someone concerned about blowing the stack. Divorce IRQ stack configuration from CONFIG_4KSTACKS, as it's believed to be an important safety measure regardless of stack size by some users. Signed-off-by: William Irwin Index: stack-paranoia/arch/i386/Kconfig.debug =================================================================== --- stack-paranoia.orig/arch/i386/Kconfig.debug 2007-04-30 10:32:56.182682722 -0700 +++ stack-paranoia/arch/i386/Kconfig.debug 2007-04-30 10:34:07.058721717 -0700 @@ -35,6 +35,14 @@ This option will slow down process creation somewhat. +config IRQSTACKS + bool "IRQ stacks" + depends on DEBUG_KERNEL + help + Arranges for per-cpu interrupt stacks so that interrupts + and interrupt-time processing don't consume space on task + stacks. + config VMALLOC_STACK bool "vmalloc() the stack" depends on DEBUG_KERNEL @@ -76,8 +84,7 @@ If you say Y here the kernel will use a 4Kb stacksize for the kernel stack attached to each process/thread. This facilitates running more threads on a system and also reduces the pressure - on the VM subsystem for higher order allocations. This option - will also use IRQ stacks to compensate for the reduced stackspace. + on the VM subsystem for higher order allocations. config 8KSTACKS bool "Use 8KB for kernel stacks" @@ -90,7 +97,6 @@ If you say Y here, the kernel will use a 16KB stacksize. This impedes running more threads on a system and also increases the pressure on the VM subsystem for higher order allocations. - This option will also use IRQ stacks to for additional safety. config 32KSTACKS bool "Use 32KB for kernel stacks" @@ -98,15 +104,14 @@ If you say Y here, the kernel will use a 32KB stacksize. This impedes running more threads on a system and also increases the pressure on the VM subsystem for higher order allocations. - This option will also use IRQ stacks to for additional safety. config 64KSTACKS bool "Use 64KB for kernel stacks" + depends on !IRQSTACKS help If you say Y here, the kernel will use a 64KB stacksize. This impedes running more threads on a system and also increases the pressure on the VM subsystem for higher order allocations. - This option will also use IRQ stacks to for additional safety. endchoice Index: stack-paranoia/arch/i386/kernel/irq.c =================================================================== --- stack-paranoia.orig/arch/i386/kernel/irq.c 2007-04-30 10:26:15.967875780 -0700 +++ stack-paranoia/arch/i386/kernel/irq.c 2007-04-30 10:34:07.058721717 -0700 @@ -47,7 +47,7 @@ #endif } -#ifdef CONFIG_4KSTACKS +#ifdef CONFIG_IRQSTACKS /* * per-CPU IRQ handling contexts (thread information and stack) */ @@ -71,7 +71,7 @@ /* high bit used in ret_from_ code */ int irq = ~regs->orig_eax; struct irq_desc *desc = irq_desc + irq; -#ifdef CONFIG_4KSTACKS +#ifdef CONFIG_IRQSTACKS union irq_ctx *curctx, *irqctx; u32 *isp; #endif @@ -99,7 +99,7 @@ } #endif -#ifdef CONFIG_4KSTACKS +#ifdef CONFIG_IRQSTACKS curctx = (union irq_ctx *) current_thread_info(); irqctx = hardirq_ctx[smp_processor_id()]; @@ -144,7 +144,7 @@ return 1; } -#ifdef CONFIG_4KSTACKS +#ifdef CONFIG_IRQSTACKS /* * These should really be __section__(".bss.page_aligned") as well, but Index: stack-paranoia/include/asm-i386/irq.h =================================================================== --- stack-paranoia.orig/include/asm-i386/irq.h 2007-04-30 10:26:31.904783972 -0700 +++ stack-paranoia/include/asm-i386/irq.h 2007-04-30 10:34:07.058721717 -0700 @@ -24,7 +24,7 @@ # define ARCH_HAS_NMI_WATCHDOG /* See include/linux/nmi.h */ #endif -#ifdef CONFIG_4KSTACKS +#ifdef CONFIG_IRQSTACKS extern void irq_ctx_init(int cpu); extern void irq_ctx_exit(int cpu); # define __ARCH_HAS_DO_SOFTIRQ Index: stack-paranoia/include/asm-i386/module.h =================================================================== --- stack-paranoia.orig/include/asm-i386/module.h 2007-04-30 10:32:56.182682722 -0700 +++ stack-paranoia/include/asm-i386/module.h 2007-04-30 10:34:07.058721717 -0700 @@ -80,7 +80,13 @@ #define MODULE_VMALLOC_STACK "" #endif +#ifdef CONFIG_IRQSTACKS +#define MODULE_IRQSTACKS "IRQSTACKS " +#else +#define MODULE_IRQSTACKS "" +#endif + #define MODULE_ARCH_VERMAGIC MODULE_PROC_FAMILY MODULE_STACKSIZE \ - MODULE_VMALLOC_STACK + MODULE_VMALLOC_STACK MODULE_IRQSTACKS #endif /* _ASM_I386_MODULE_H */