linux-kernel - Re: [PATCH] x86, efi: Break up large initrd reads

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Date:	Fri, 25 Nov 2011 08:48:19 +0000
From:	Matt Fleming <matt@...sole-pimps.org>
To:	Maarten Lankhorst <m.b.lankhorst@...il.com>
Cc:	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Matthew Garrett <mjg@...hat.com>, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
	Mike Waychison <mikew@...gle.com>,
	Andi Kleen <andi@...stfloor.org>,
	Peter Jones <pjones@...hat.com>
Subject: Re: [PATCH] x86, efi: Break up large initrd reads

On Fri, 2011-11-25 at 02:37 +0100, Maarten Lankhorst wrote:
> The efi boot stub tries to read the entire initrd in 1 go,
> however some efi implementations hang if too much if asked
> to read too much data at the same time. After some
> experimentation I found out that my asrock p67 board will
> hang if asked to read chunks of 4mb, so use a safe value.
> 
> From elilo source code:
> /*
>  * We load by chunks rather than a single big read because
>  * early versions of EFI had troubles loading files
>  * from floppies in a single big request.  Breaking
>  * the read down into chunks of 4KB fixed that
>  * problem. While this problem has been fixed, we still prefer
>  * this method because it tells us whether or not we're making
>  * forward progress.
>  */
> 
> While the comment says 4KB, it's using 4 * EFI_PAGE_SIZE (16KB),
> so I went by the safest route of following elilo here.
> 
> Signed-off-by: Maarten Lankhorst <m.b.lankhorst@...il.com>
> ---
>  arch/x86/boot/compressed/eboot.c |   20 ++++++++++++++------
>  1 files changed, 14 insertions(+), 6 deletions(-)

Thanks Maarten, applied!

-- 
Matt Fleming, Intel Open Source Technology Center

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