Re: [PATCH 13/19] x86, mm: only call early_ioremap_page_table_range_init()once

From: Yinghai Lu
Date: Mon Oct 22 2012 - 15:40:06 EST

On Mon, Oct 22, 2012 at 8:24 AM, Konrad Rzeszutek Wilk
<konrad@xxxxxxxxxx> wrote:
> On Thu, Oct 18, 2012 at 01:50:24PM -0700, Yinghai Lu wrote:
>> On 32bit, We should not keep calling that during every init_memory_mapping.
> Explain pls why.

clear ?

On 32bit, before patcheset that only set page table for ram, we only
call that one time.

Now, we are calling that during every init_memory_mapping if we have holes
under max_low_pfn.

We should only call it one time after all ranges under max_low_page get
mapped just like we did before.

Also that could avoid the risk to run out of pgt_buf in BRK.

Need to update page_table_range_init() to count the pages for kmap page table
at first, and use new added alloc_low_pages() to get pages in sequence.
That will conform to the requirement that pages need to be in low to high order.
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