From: Cliff Wickman <cpw@sgi.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: kexec@lists.infradead.org
Subject: Re: 896MB address limit
Date: Tue, 25 Sep 2012 09:18:34 -0500 [thread overview]
Message-ID: <20120925141834.GA6184@sgi.com> (raw)
In-Reply-To: <877grissof.fsf@xmission.com>
Hi Eric, and all,
On Mon, Sep 24, 2012 at 08:11:12PM -0700, Eric W. Biederman wrote:
> Cliff Wickman <cpw@sgi.com> writes:
>
> > Gentlemen,
> >
> > In dumping very large memories we are running up against the 896MB
> > limit in SLES11SP2 (3.0.38 kernel).
>
> Odd. That limit should be the maximum address in memory to load the
> crash kernel. Tha limit should have nothing to do with the dump process
> itself.
>
> Are you saying you need more that 512MiB reserved for the crash kernel
> to be able to dump all of the memory in your system?
>
> Eric
As I noted to Eric privately, yes we need to bump up to crashkernel=1G
or more for some very large memories.
As an experiment I bumped
+++ linux/arch/x86/kernel/setup.c
@@ -528,7 +528,7 @@ static inline unsigned long long get_tot
#ifdef CONFIG_X86_32
# define CRASH_KERNEL_ADDR_MAX (512 << 20)
#else
-# define CRASH_KERNEL_ADDR_MAX (896 << 20)
+# define CRASH_KERNEL_ADDR_MAX (1700 << 20)
And that seems to work. i.e. I'm currently dumping a system where
crashkernel=1G and it seems to be working.
Am I just living dangerously?
-Cliff
--
Cliff Wickman
SGI
cpw@sgi.com
(651) 683-3824
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next prev parent reply other threads:[~2012-09-25 14:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-24 23:07 896MB address limit Cliff Wickman
2012-09-25 3:11 ` Eric W. Biederman
2012-09-25 14:18 ` Cliff Wickman [this message]
2012-09-25 15:10 ` Eric W. Biederman
2012-09-25 15:57 ` Maxim Uvarov
2012-09-25 15:58 ` Maxim Uvarov
2012-09-27 23:07 ` Cliff Wickman
2012-09-25 17:38 ` Vivek Goyal
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