From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bn1on0137.outbound.protection.outlook.com ([157.56.110.137] helo=na01-bn1-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZuDY4-0002Jo-1j for kexec@lists.infradead.org; Thu, 05 Nov 2015 05:57:25 +0000 Message-ID: <1446703011.12676.83.camel@freescale.com> Subject: Re: [PATCH] kexec: Add --lite option From: Scott Wood Date: Wed, 4 Nov 2015 23:56:51 -0600 In-Reply-To: <1445540891.30908.144.camel@infradead.org> References: <1445469125.30908.105.camel@infradead.org> <20151022031718.GB11227@dhcp-129-115.nay.redhat.com> <20151022125012.GB20847@redhat.com> <1445540891.30908.144.camel@infradead.org> MIME-Version: 1.0 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: Geoff Levand Cc: panand@redhat.com, kexec@lists.infradead.org, Simon Horman , Petitboot@lists.ozlabs.org, Dave Young , Vivek Goyal On Thu, 2015-10-22 at 12:08 -0700, Geoff Levand wrote: > Hi Vivek, > > On Thu, 2015-10-22 at 08:50 -0400, Vivek Goyal wrote: > > On Thu, Oct 22, 2015 at 11:17:18AM +0800, Dave Young wrote: > > > On 10/21/15 at 04:12pm, Geoff Levand wrote: > > > > Add a new option --lite to kexec that allows for a fast reboot > > > > by avoiding the purgatory integrity checks. This option is > > > > intended for use by kexec based bootloaders that load a new > > > > image and then immediately transfer control to it. > > > > > > I think Vivek was rejecting this --lite since kdump need the purgatory > > > integrity checks. Ccing him. > > > > Right. Why are we trying to bypass sha256 hash verification of loaded > > segments at run time, that needs to be justified. > > Please see my reply to Dave. > > > Atleast on x86, this integrity verification was fast and we did not > > notice any siginificant delays in purgatory. And in that case extra knob > > like this is hard to justify. > > I notice the difference on the my arm64 system, so I guess we > are even on that. For me it was beyond "notice the difference" -- I thought it was completely broken, and was preparing to debug, until it started spitting out output over a minute later. Compiling the sha256 code with -O2 instead of -O0 cut it down to around 10 seconds (still unpleasant, but not quite as crazy... still unacceptable for non-kdump, though). There was a patch posted a couple years ago to do that -- does anyone know what happened to it? http://kexec.infradead.narkive.com/JSemzXoT/patch-purgatory-compile-sha256-c-only-on-ia64-with-o0 -Scott _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec