Re: [PATCH RESEND 2/3] x86, mm: Update min_pfn_mapped in add_pfn_range_mapped().

Yinghai Lu
2013-09-03T02:48:15Z

On Mon, Sep 2, 2013 at 6:06 PM, Tang Chen <tangchen@cn.fujitsu.com> wrote:
> Hi Yinghai,
>
> On 09/03/2013 02:41 AM, Yinghai Lu wrote:

> How about change the "for (from low to high)" in init_range_memory_mapping()
> to
> "for_rev(from high to low)" ?
> Then we can update min_pfn_mapped in add_pfn_range_mapped().
>
> And also, the outer loop is from high to low, we can change the inner loop
> to be from high
> to low too.

No. there is other reason for doing local from low to high.

kernel_physical_mapping_init() could clear some mapping near the end
of PUG/PMD entries but not the head.

>
> I think updating min_pfn_mapped in init_mem_mapping() is less readable. And
> min_pfn_mapped
> and max_pfn_mapped should be updated together.

min_pfn_mapped is early local variable to control allocation in alloc_low_pages.
put it in init_mem_mapping is more readable.

Yinghai