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

[Russell King - ARM Linux]

On Wed, Jan 15, 2014 at 10:22:02AM +0000, Catalin Marinas wrote:
> 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).

Why do you ask about boot time?

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