search

CachyOS / CachyOS-Settings

Settings used for CachyOS
GNU General Public License v3.0
91 stars 22 forks source link

udev: Add ZRAM recompression by default #13

Closed ventureoo closed 1 year ago

ventureoo commented 1 year ago

Since we already have CONFIG_ZRAM_MULTI_COMP enabled in our kernel, I thought that we could provide by default recompressions to ZRAM. Double compression will save more memory for those pages that cannot be compressed with Zstd (since we use it by default), in this PR I decided to set double compression only for idle pages, since huge pages were reverted with the commit https://github.com/CachyOS/CachyOS-Settings/commit/48f40a564135a80ff23463d66e129856bbdcfe38. The re-compression algorithm can be changed in the future, for now I stopped at LZ4.

This was done as a udev rule as a temporary solution, since it is better to have this feature directly in the zram-generator, but until it is absent we will limit ourselves to this rule.

It also works only for kernel versions 6.2 and higher, for versions of the kernel below this should not create due to the checks (I tested at linux-zen 6.1, no errors).

Note: I know that recompression may cause additional CPU overhead, but I don't think it will be too critical. Additionally, we can limit this via the threshold parameter. Anyway, it's interesting to hear your opinion @sirlucjan @ptr1337

ptr1337 commented 1 year ago

I need to test this first. @ventureoo How your testing was ? Did something improved at your side?

sirlucjan commented 1 year ago

I'll test it tomorrow.