From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jay Lan Date: Mon, 20 Nov 2006 23:33:25 +0000 Subject: Re: [PATCH]send slave cpus to SAL slave loop on crash (IA64) Message-Id: <45623B45.7060302@sgi.com> List-Id: References: <4546623D.5000105@engr.sgi.com> In-Reply-To: <4546623D.5000105@engr.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Zou, Nanhai wrote: >> We do not rely on machine crash on CPU 0 any more. If the >> crashing CPU is not cpu 0 and the cpu 0 not being returned to >> the slave loop, this case is handled by our PROM now. >> >> However, if somebody tries to boot up a production kernel using '-le' >> option _after_ the kexec'ed kernel is up running, the third kernel >> would not boot unless we boot up the second kernel with cpu 0. I >> posted a question on "if running 'kexec -le' on a kexec'ed kdump >> kernel is legal" earlier and Vivek responded saying the scenario >> is not guranteed to work. So, i think we are fine here. >> > > Ok, so with this patch and the PROM fix, on a SN system, > 1. Kdump -> 2nd kernel works. > 2. Kdump -> 2nd kernel -> Kexec to third kernel will not work. > 3. Kexec -> 2nd Kernel -> Kexec -> 3rd kernel works? > 4. Kexec -> 2nd Kernel -> Kdump -> 3rd kernel works? > > I think if scenario 1, 3 and 4 works it will be ok. Scenario 2 is not so useful I guess. > With the patch Nanhai sent to me to fix '-l' option on SN system, now scenario 1, 3 and 4 all works. Of course, you need to include 'crashkernel' parameter in "append" option when you do 'kexec -l' in order for scenario #4 to work. You do not need crashkernel parameter for #3 though. Thanks, - jay