Re: [PATCH 3/3] x86, crash: Allocate enough low-mem when crashkernel=high

From: Joerg Roedel <jroedel@suse.de>
To: Baoquan He <bhe@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>, Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] x86, crash: Allocate enough low-mem when crashkernel=high
Date: Wed, 4 Feb 2015 15:10:20 +0100	[thread overview]
Message-ID: <20150204141020.GB10078@suse.de> (raw)
In-Reply-To: <20150201084103.GB1573@dhcp-17-102.nay.redhat.com>

Hi Baoquan,

On Sun, Feb 01, 2015 at 04:41:03PM +0800, Baoquan He wrote:
> Before I said 256M may not be a good value, that's because in your patch
> cover you said this number comes from experiments on the affected
> systems, and 128M was still not enough, then you set it to 256M. This
> may be a little rush. I think the step size to increase should be 32M,
> after all previously people only take 64M and 8M, enlarge it on a step
> size of 128M only one time, it can't be seen as patient and careful.
> If it failed on 224M but succeed on 256M, then 256M may be not enough.
> I would like to say 32M is better, then we can make a good evaluate.

That makes sense. I also asked the customer to test intermediate values,
we already know that it works with 256MB but also that 128MB are not
enough. I will report back when I have the results of the intermediate
values in 32MB steps.

Thanks,

	Joerg