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

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Message-ID: <20131121233104.GF1106@anatevka.fc.hp.com>
Date:	Thu, 21 Nov 2013 16:31:04 -0700
From:	jerry.hoemann@...com
To:	Matthew Garrett <mjg59@...f.ucam.org>
Cc:	rob@...dley.net, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, matt.fleming@...el.com,
	yinghai@...nel.org, akpm@...ux-foundation.org, bp@...e.de,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-efi@...r.kernel.org, penberg@...nel.org,
	mingo.kernel.org@...il.com, vgoyal@...hat.com
Subject: Re: [RFC v2 0/2] Early use of boot service memory

On Thu, Nov 21, 2013 at 11:07:44PM +0000, Matthew Garrett wrote:
> On Thu, Nov 21, 2013 at 02:01:24PM -0700, Jerry Hoemann wrote:
> > 
> > Some platform have firmware that violates the UEFI spec and access boot
> > service code or data segments after the system has called ExitBootServices().
> > The call to efi_reserve_boot_services in setup_arch is a workaround to
> > avoid using boot service memory until after the kernel has done
> > SetVirtualAddressMap.  However, this reservation fragments memory
> > which can cause large allocations early in boot (e.g. crash kernel)
> > to fail.
> 
> 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?


Hi Matthew,

I tried this back on 3.11 kernel and reserve_crashkernel after free of
boot services failed.  I will admit to not digging in too deeply as to
why it failed.

My earlier email:

https://lkml.org/lkml/2013/9/18/457


thanks


> 
> -- 
> Matthew Garrett | mjg59@...f.ucam.org

-- 

----------------------------------------------------------------------------
Jerry Hoemann            Software Engineer              Hewlett-Packard

3404 E Harmony Rd. MS 57                        phone:  (970) 898-1022
Ft. Collins, CO 80528                           FAX:    (970) 898-XXXX
                                                email:  jerry.hoemann@...com
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