Re: [PATCH v4 0/2] mm/highmem: make kmap cache coloring aware

From: Leonid Yegoshin
Date: Tue Aug 26 2014 - 14:38:10 EST


16KB page size solution may sometime be a solution:

1) in microcontroller environment then small pages have advantage
in small applications world.

2) some kernel drivers may not fit well a different page size, especially if HW
has an embedded memory translation: GPU, video/audio decoders,
supplement accelerators.

3) finally, somebody can increase cache size faster than page size,
this race never finishes.



Ralf Baechle <ralf@xxxxxxxxxxxxxx> wrote:


On Sat, Aug 02, 2014 at 05:11:37AM +0400, Max Filippov wrote:

> this series adds mapping color control to the generic kmap code, allowing
> architectures with aliasing VIPT cache to use high memory. There's also
> use example of this new interface by xtensa.

I haven't actually ported this to MIPS but it certainly appears to be
the right framework to get highmem aliases handled on MIPS, too.

Though I still consider increasing PAGE_SIZE to 16k the preferable
solution because it will entirly do away with cache aliases.

Thanks,

Ralf
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