From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH] x86: keep the crash kernel below 896 MiB Date: Thu, 25 Apr 2013 11:48:09 +0100 Message-ID: <517909E9.2010100@citrix.com> References: <1366880223-15439-1-git-send-email-warner.wang@hp.com> <517918B502000078000D0A56@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <517918B502000078000D0A56@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich , Warner Wang Cc: "Keir (Xen.org)" , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 25/04/13 10:51, Jan Beulich wrote: >>>> On 25.04.13 at 10:57, Warner Wang wrote: >> When use the crashkernel=size parameter without specifying a "@xM" >> suffix, the crashkernel will be reserved at the highest suitable >> address of memory, this will make the kexec-tools fail to work. >> The current kexec-tools have a limitation that it can only work >> with crashkernel reserved under 896 MiB. we can increase this >> limit once kexec-tools are fixed. >> Linux kernel itself have this code for kexec-tools limitation, >> so I think Xen code should also have it. > Andrew, > > didn't you post something along those lines at some point too, > yet there was a reason it never got applied? > > Jan Jan: I have some low crashinfo patches but they are in. It was for positioning of the Xen per-cpu crash notes and the console ring. Warner: I am curious to know what this magic 896MiB limit is. Do you have a reference to the problem. ~Andrew > >> --- a/xen/arch/x86/setup.c >> +++ b/xen/arch/x86/setup.c >> @@ -943,6 +943,13 @@ void __init __start_xen(unsigned long mbi_p) >> } >> } >> >> + /* >> + * Keep the crash kernel below this limit. On 64 bits, kexec-tools >> + * currently limits us to 896 MiB; increase this limit once kexec-tools >> + * are fixed. >> + */ >> + e = min_t(uint64_t, e, 896 << 20); >> + >> /* Don't overlap with modules. */ >> e = consider_modules(s, e, PAGE_ALIGN(kexec_crash_area.size), >> mod, mbi->mods_count, -1); >> -- >> 1.7.1 > >