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Date: Mon, 10 Oct 2011 12:55:47 -0500
From: Scott Wood <scottwood@freescale.com>
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To: Suzuki Poulose <suzuki@in.ibm.com>
Subject: Re: [PATCH 1/3] [powerpc32] Process dynamic relocations for kernel
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Cc: Michal Simek <monstr@monstr.eu>, tmarri@apm.com,
 Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>,
 Dave Hansen <dave@linux.vnet.ibm.com>, David Laight <David.Laight@ACULAB.COM>,
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On 10/10/2011 12:17 PM, Suzuki Poulose wrote:
> On 10/10/11 20:45, Scott Wood wrote:
>> On 10/10/2011 04:55 AM, Suzuki K. Poulose wrote:
>>> The following patch implements the dynamic relocation processing for
>>> PPC32 kernel. relocate() accepts the target virtual address and
>>> relocates
>>>   the kernel image to the same.
>>
>> How much overhead is involved in a true relocatable kernel?  Is it worth
>> preserving the old "relocatable" booke behavior under a different name?
> 
> There are '75782' on an ebony kernel with minimal config. So thats a
> pretty big
> number for small embedded chips. I guess, preserving the 'old
> relocatable' (page
> aligned approach) would be a good idea for the architectures which can
> afford it.
> e.g, places where TLB size is 64M or less.

The systems we've been using this option on aren't *that* small -- I was
thinking more about runtime overhead (beyond the time taken at boot to
process relocations).

-Scott