Re: Re: [PATCH 0/1] arm64/sparsemem: reduce SECTION_SIZE_BITS

On 1/21/21 1:26 PM, Will Deacon wrote:

On Wed, 20 Jan 2021 21:29:12 -0800, Sudarshan Rajagopalan wrote:

quoted

This patch is the follow-up from the discussions in the thread [1].
Reducing the section size has the merit of reducing wastage of reserved memory
for vmmemmap mappings for sections with large memory holes. Also with smaller
section size gives more grunularity and agility for memory hot(un)plugging.

But there are also constraints in reducing SECTION_SIZE_BIT:

[...]

Applied to arm64 (for-next/misc), thanks!

We have been using 128M for 4K pages for a while, using patch [1] without issues.

One thing that needs to be also modified is makedumpfile [2]- line 76, must update it SECTIONS_SIZE_BITS based on the PAGESIZE.

[1] https://lore.kernel.org/lkml/20190423203843.2898-1-pasha.tatashin@soleen.com/ (local)
[2] https://sourceforge.net/p/makedumpfile/code/ci/master/tree/arch/arm64.c

[1/1] arm64/sparsemem: reduce SECTION_SIZE_BITS
      https://git.kernel.org/arm64/c/f0b13ee23241

Cheers,

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