From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754936AbeASImg (ORCPT ); Fri, 19 Jan 2018 03:42:36 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42892 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754070AbeASIma (ORCPT ); Fri, 19 Jan 2018 03:42:30 -0500 Date: Fri, 19 Jan 2018 16:42:23 +0800 From: Dave Young To: Sergey Senozhatsky Cc: Andi Kleen , pmladek@suse.com, sergey.senozhatsky@gmail.com, rostedt@goodmis.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, kexec@lists.infradead.org Subject: Re: [PATCH] print kdump kernel loaded status in stack dump Message-ID: <20180119084223.GC3985@dhcp-128-65.nay.redhat.com> References: <20180117045057.GA4994@dhcp-128-65.nay.redhat.com> <878tcvt592.fsf@linux.intel.com> <20180119054538.GA484@jagdpanzerIV> <20180119081628.GB3985@dhcp-128-65.nay.redhat.com> <20180119082835.GA477@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180119082835.GA477@jagdpanzerIV> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/19/18 at 05:28pm, Sergey Senozhatsky wrote: > On (01/19/18 16:16), Dave Young wrote: > > On 01/19/18 at 02:45pm, Sergey Senozhatsky wrote: > > > On (01/18/18 10:02), Andi Kleen wrote: > > > > Dave Young writes: > > > > > printk("%sHardware name: %s\n", > > > > > log_lvl, dump_stack_arch_desc_str); > > > > > + if (kexec_crash_loaded()) > > > > > + printk("%skdump kernel loaded\n", log_lvl); > > > > > > > > Oops/warnings are getting longer and longer, often scrolling away > > > > from the screen, and if the kernel crashes backscroll does not work > > > > anymore, so precious information is lost. > > > > > > true. I even ended up having a console_reflush_on_panic() function. it > > > simply re-prints with a delay [so I can at least read the oops] logbuf > > > entries every once in a while, staring with the first oops_in_progress > > > record. > > > > > > > If too many messages printed on screen, then the next flush will > > still scroll up. > > right. but it re-prints Oops with a new console_unlock_delay() delay > which gives me enough time to either read it as many times as I want, > or take a picture, etc. it's not as fast as the normal oops print out. > > [I'm not entirely sure I see why do we have printk_delay() in > vprintk_emit()... I mean I probably can see some reasoning behind > it, but at the same it makes sense to slow down console_unlock() > as well] Looks like I am the guy who added the code :) Actually no special reason, just did not thinking about the performance issue at all at that time.. > > -ss From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1ecSG1-0002jf-Pn for kexec@lists.infradead.org; Fri, 19 Jan 2018 08:42:43 +0000 Date: Fri, 19 Jan 2018 16:42:23 +0800 From: Dave Young Subject: Re: [PATCH] print kdump kernel loaded status in stack dump Message-ID: <20180119084223.GC3985@dhcp-128-65.nay.redhat.com> References: <20180117045057.GA4994@dhcp-128-65.nay.redhat.com> <878tcvt592.fsf@linux.intel.com> <20180119054538.GA484@jagdpanzerIV> <20180119081628.GB3985@dhcp-128-65.nay.redhat.com> <20180119082835.GA477@jagdpanzerIV> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180119082835.GA477@jagdpanzerIV> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Sergey Senozhatsky Cc: pmladek@suse.com, Andi Kleen , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, sergey.senozhatsky@gmail.com, akpm@linux-foundation.org On 01/19/18 at 05:28pm, Sergey Senozhatsky wrote: > On (01/19/18 16:16), Dave Young wrote: > > On 01/19/18 at 02:45pm, Sergey Senozhatsky wrote: > > > On (01/18/18 10:02), Andi Kleen wrote: > > > > Dave Young writes: > > > > > printk("%sHardware name: %s\n", > > > > > log_lvl, dump_stack_arch_desc_str); > > > > > + if (kexec_crash_loaded()) > > > > > + printk("%skdump kernel loaded\n", log_lvl); > > > > > > > > Oops/warnings are getting longer and longer, often scrolling away > > > > from the screen, and if the kernel crashes backscroll does not work > > > > anymore, so precious information is lost. > > > > > > true. I even ended up having a console_reflush_on_panic() function. it > > > simply re-prints with a delay [so I can at least read the oops] logbuf > > > entries every once in a while, staring with the first oops_in_progress > > > record. > > > > > > > If too many messages printed on screen, then the next flush will > > still scroll up. > > right. but it re-prints Oops with a new console_unlock_delay() delay > which gives me enough time to either read it as many times as I want, > or take a picture, etc. it's not as fast as the normal oops print out. > > [I'm not entirely sure I see why do we have printk_delay() in > vprintk_emit()... I mean I probably can see some reasoning behind > it, but at the same it makes sense to slow down console_unlock() > as well] Looks like I am the guy who added the code :) Actually no special reason, just did not thinking about the performance issue at all at that time.. > > -ss _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec