Re: [PATCH v2 00/13] arch, mm: deprecate DISCONTIGMEM

John Paul Adrian Glaubitz
2020-11-17T05:24:51Z

Hi!

On 11/1/20 6:04 PM, Mike Rapoport wrote:
> It's been a while since DISCONTIGMEM is generally considered deprecated,
> but it is still used by four architectures. This set replaces DISCONTIGMEM
> with a different way to handle holes in the memory map and marks
> DISCONTIGMEM configuration as BROKEN in Kconfigs of these architectures with
> the intention to completely remove it in several releases.
>
> While for 64-bit alpha and ia64 the switch to SPARSEMEM is quite obvious
> and was a matter of moving some bits around, for smaller 32-bit arc and
> m68k SPARSEMEM is not necessarily the best thing to do.
>
> On 32-bit machines SPARSEMEM would require large sections to make section
> index fit in the page flags, but larger sections mean that more memory is
> wasted for unused memory map.
>
> Besides, pfn_to_page() and page_to_pfn() become less efficient, at least on
> arc.
>
> So I've decided to generalize arm's approach for freeing of unused parts of
> the memory map with FLATMEM and enable it for both arc and m68k. The
> details are in the description of patches 10 (arc) and 13 (m68k).

Apologies for the late reply. Is this still relevant for testing?

I have already successfully tested v1 of the patch set, shall I test v2?

Adrian

--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@debian.org
`. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
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