Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751831AbYCJPCo (ORCPT ); Mon, 10 Mar 2008 11:02:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751517AbYCJPCd (ORCPT ); Mon, 10 Mar 2008 11:02:33 -0400 Received: from mx1.redhat.com ([66.187.233.31]:56802 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751471AbYCJPCb (ORCPT ); Mon, 10 Mar 2008 11:02:31 -0400 Message-ID: <47D54C7E.3010304@redhat.com> Date: Mon, 10 Mar 2008 09:58:06 -0500 From: Larry Woodman User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.2) Gecko/20040301 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton CC: Rik van Riel , linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] extend sysrq-p functionality to cover all CPUs References: <20080309221458.20642e48@bree.surriel.com> <20080309224759.6fead9af.akpm@linux-foundation.org> In-Reply-To: <20080309224759.6fead9af.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2287 Lines: 74 Andrew Morton wrote: >On Sun, 9 Mar 2008 22:14:58 -0400 Rik van Riel wrote: > > > >>SysRP-P is not all that useful on SMP systems, since the sysrq >>irq rarely ends up on the CPU that we actually want to investigate. >> >>This patch extends sysrq-p to print a backtrace for every CPU, >>not just the lucky one that gets the sysrq irq. With this patch, >>"echo p > /proc/sysrq-trigger" does something useful. >> >>Signed-off-by: Rik van Riel >> >>diff -up linux-2.6.25-rc3-mm1/drivers/char/sysrq.c.multicpu linux-2.6.25-rc3-mm1/drivers/char/sysrq.c >>--- linux-2.6.25-rc3-mm1/drivers/char/sysrq.c.multicpu 2008-03-09 20:22:17.000000000 -0400 >>+++ linux-2.6.25-rc3-mm1/drivers/char/sysrq.c 2008-03-09 21:54:02.000000000 -0400 >>@@ -196,11 +196,29 @@ static struct sysrq_key_op sysrq_showloc >> #define sysrq_showlocks_op (*(struct sysrq_key_op *)0) >> #endif >> >>+static DEFINE_SPINLOCK(show_lock); >>+static void showacpu(void *dummy) >>+{ >>+ struct pt_regs *regs = get_irq_regs(); >>+ >>+ spin_lock(&show_lock); >>+ printk("CPU%d:\n", smp_processor_id()); >>+ show_stack(NULL, NULL); >>+ spin_unlock(&show_lock); >>+} >>+static void sysrq_showregs_othercpus(struct work_struct *dummy) >>+{ >>+ smp_call_function(showacpu, NULL, 0, 0); >>+} >>+static DECLARE_WORK(sysrq_showregs, sysrq_showregs_othercpus); >> static void sysrq_handle_showregs(int key, struct tty_struct *tty) >> { >> struct pt_regs *regs = get_irq_regs(); >>- if (regs) >>+ if (regs) { >>+ printk("CPU%d:\n", smp_processor_id()); >> show_regs(regs); >>+ } >>+ schedule_work(&sysrq_showregs); >> } >> static struct sysrq_key_op sysrq_showregs_op = { >> .handler = sysrq_handle_showregs, >> >> > >Doesn't everyone have a copy of this somewhere? ;) > Yes, but we use W instead of P. Dont you want to keep the old AlsSysrq P and add a new SPM version using a defferent letter ? Larry > >However it does have the downside that info can scroll away on large cpu >counts. Maybe it should be a new sysrq command? > > > -- 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/