Re: [RFC v2 0/2] Early use of boot service memory

jerry.hoemann
2013-11-22T01:25:31Z

On Thu, Nov 21, 2013 at 05:12:57PM -0800, H. Peter Anvin wrote:
> On 11/21/2013 03:37 PM, Matthew Garrett wrote:
> > On Thu, Nov 21, 2013 at 03:18:41PM -0800, H. Peter Anvin wrote:
> >> On 11/21/2013 03:07 PM, Matthew Garrett wrote:
> >>> This is a problem we have to solve, but I don't think this is the right
> >>> way to solve it. Why do we not just reattempt to perform the allocation
> >>> immediately after we've freed the boot services regions?
> >>>
> >>
> >> Wouldn't the memory map already have gotten scrambled all to hell by then?
> >
> > If we couldn't map a 64MB region in low memory earlier then it's likely
> > to have been because there was a 64MB or greater boot services region.
> >
>
> I thought the problem was that they wanted to map a fairly large chunk
> for faster kdump and fragmentation was being a problem.
>
> -hpa

larger crash dump reservation is not so much performance as functionality.

Large systems w/ lots of IO require large crash kernel allocations for
the kernel to boot. Then you have to worry about the OOM killer.....

makedumpfile going to cyclic buffer has helped out greatly, but on
our new systems we're still looking at 512 MB crash kernels.

--

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Jerry Hoemann Software Engineer Hewlett-Packard

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