From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from co1ehsobe004.messaging.microsoft.com ([216.32.180.187] helo=co1outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UxmJW-0000v2-69 for kexec@lists.infradead.org; Fri, 12 Jul 2013 22:59:47 +0000 Message-ID: <51E08A40.80900@mail.usask.ca> Date: Fri, 12 Jul 2013 16:59:12 -0600 From: Chris Friesen MIME-Version: 1.0 Subject: Re: visible memory seems wrong in kexec crash dump kernel References: <51DF1BBB.5060904@mail.usask.ca> <51DF2229.5010604@mail.usask.ca> <20130712012142.GA24112@concordia> <51E07056.8040007@mail.usask.ca> In-Reply-To: <51E07056.8040007@mail.usask.ca> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Michael Ellerman Cc: Benjamin Herrenschmidt , kexec@lists.infradead.org, Haren Myneni , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Vivek Goyal On 07/12/2013 03:08 PM, Chris Friesen wrote: > I turned on the instrumentation in early_init_dt_scan_memory() and got > the following when jumping to the capture kernel: > > memory scan node memory, reg size 16, data: 0 0 2 0, > - 0 , 200000000 > > That 0x200000000 matches the fact that I'm seeing 8GB of memory > available in the recovery kernel. > > If I boot the original kernel with "crashkernel=224M@32M", should I > expect that only 224MB is marked as "linux,usable-memory" in the > recovery kernel? I started looking at the kexec side of things, and I noticed something a bit odd. In most places dealing with the device tree in kexec it accepts either "memory" or "memory@" for the memory node name. In add_usable_mem_property() in arch/ppc64/fs2dt.c it seems to only accept "memory@". Is this expected behaviour? It seems to be the same in current git versions of kexec-tools. On my system I see "/proc/device-tree/memory". If I modify add_usable_mem_property() to also accept "/memory" then my recovery kernel boots up with physicalMemorySize = 0x10000000 which is 256MB (which is still a bit odd since I specified 224MB for the crashkernel). However, it then hits the BUG() call at the end of mark_bootmem() in mm/bootmem.c. Chris _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec