linux-kernel - Re: [PATCH] x86, kdump: Set crashkernel

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Message-ID: <CAE9FiQUu-AwKhsAdUautjxduW5a-pxpv8XFY-p1LWSmb-itATg@mail.gmail.com>
Date:	Mon, 11 Mar 2013 11:44:16 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Vivek Goyal <vgoyal@...hat.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>, WANG Chao <chaowang@...hat.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86, kdump: Set crashkernel_low automatically

On Mon, Mar 11, 2013 at 11:26 AM, Vivek Goyal <vgoyal@...hat.com> wrote:
> On Mon, Mar 11, 2013 at 10:58:39AM -0700, Yinghai Lu wrote:
>> On Mon, Mar 11, 2013 at 8:02 AM, Vivek Goyal <vgoyal@...hat.com> wrote:
>> >
>> > IOW, wouldn't it be better that crashkernel=X first tries to find
>> > requested amount of memory in lowest memory area available/possible.
>>
>> Yest, that is much better, and user even could stay with old kexec-tools
>> for system that does not tons of memory.
>> And I don't need to mess up with auto setting crashkernel_low or export
>> swiotlb_size() etc.
>>
>> Please check if you are ok with attached one.
>>
> Hi Yinghai,
>
> In mutt your patches are showing as attachment instead of inline. Mutt
> thinks attachment is of type "application/octet-stream". Not sure if
> this is configuration issue on my part or something is going on your
> end.

I sent it via gmail and it only can have attachment instead of inline.

>
> I have few more concerns.
>
> - Are we able to reserve 512MB memory now below 896MB. I remember so
>   far it was broken.

It also depends BIOS memmap layout. some bios put reserved on middle of ram
like just below 512M or just 2G.

>
> - If reserving memory below 896MB fails, we immediately switch to
>   reserving anywhere till MAXMEM. Would it make sense to first try
>   to reserve it below 4G (so that we don't have to worry much about
>   swiotlb or iommu being on).

ok.

Attached again.

Thanks

Yinghai

Download attachment "fix_crashkernel_low_v2.patch" of type "application/octet-stream" (3329 bytes)