Re: [RFC] Cachemap for 2.6.12rc4-mm1. Was Re: [PATCH] enhance x86 MTRR handling

Andi Kleen
2005-05-13T13:29:54Z

> : x86-64 will need updating to also take advantage of this.
> It may be able to just copy the i386 includes as-is, I've
> not looked closely at the PAT related changes on x86-64 yet. Andi?
>
> : The list manipulation macros in mm/cachemap.c are a little fugly.
>
> Anything else ?

For memory (pfn_valid == 1) it would be more memory efficient to use a few bits
in struct page->flags

In general because there are lots of uses of "range lists" it would be better
to put it as a library into lib.

Coding style needs some work.

Too many printks.

I am not sure yet the cmaps don't need reference counting. For some
cases (user space support) they probably will.

Need user space support, e.g. using the existing ioctls for /proc/bus/pci/*
(they are currently not implemented on i386/x86-64 but should with this)
Then someone would need to change the X server to use this.

Needs testing on a lot of systems.

Need to figure out if CMAP_ALLOW_OVERLAPPING should be set or not.

Probably need to go over the combining rule etc. with a fine comb

-Andi