[RFC 2/2] arm: Get rid of meminfo

[Catalin Marinas]

On 15 January 2014 09:49, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Tue, Jan 14, 2014 at 09:55:22PM -0800, Laura Abbott wrote:
>> memblock is now fully integrated into the kernel and is the prefered
>> method for tracking memory. Rather than reinvent the wheel with
>> meminfo, migrate to using memblock directly instead of meminfo as
>> an intermediate.
>
> The reason I never killed meminfo was that for some of the functions here
> is that meminfo has a slightly different property to memblock.
>
> With meminfo, each sparsemem section mapping or discontigmem node must be
> specified as a separate bank of memory, even if it is contiguous with the
> previous block.  This is so that the functions which walk the page arrays
> can do so efficiently (without having to convert from a PFN to a struct
> page for every page in the system, which is very inefficient.)

pfn_to_page() conversion is indeed expensive with sparsemem (on
32-bit) but does meminfo actually add a noticeable improvement to the
boot time? I don't think so but it's worth testing (something a
thousand cycles maximum would be lost in the noise).

-- 
Catalin