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Enable lz4, lz4hc and zstd compression support for zram for kernel 6.6 #68

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Enable lz4, lz4hc and zstd compression support for zram for kernel 6.6 #68

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5 changes: 5 additions & 0 deletions config/config
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Original file line number Diff line number Diff line change
Expand Up @@ -403,8 +403,13 @@ CONFIG_BLK_DEV_NULL_BLK=m
## file: drivers/block/zram/Kconfig
##
CONFIG_ZRAM=m
CONFIG_ZRAM_BACKEND_LZ4=y
CONFIG_ZRAM_BACKEND_LZ4HC=y
CONFIG_ZRAM_BACKEND_ZSTD=y
CONFIG_ZRAM_BACKEND_LZO=y
Comment on lines +406 to +409
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Those are not defined in Linux 6.6.79

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Hm, I thought I checked this, but maybe I made a mistake there.

Thanks for pointing that out.

Shall we close the PR, or is there a sensible replacement for those configs?

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@Vincinator Vincinator Feb 25, 2025 •
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In linux 6.6 the crypto submodule provides an interface to the compression algorithms defined in lib, e.g lib/lz4.

In 6.6 we have a chain:

Will check tomorrow what we need to enable in our configs

The interface changed in later kernel versions to a dedicated ZRAM compression backend with this patch series

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@Vincinator Vincinator Feb 25, 2025 •
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For the non-cloud kernel we have

CONFIG_ZRAM=m
CONFIG_CRYPTO_LZO=m
CONFIG_CRYPTO_LZ4=m
CONFIG_CRYPTO_LZ4HC=m
CONFIG_CRYPTO_ZSTD=m

(see here)

So it should be possible with 6.6, also according to the linked issue and the mentioned debian bug report (since we do not automatically pull in Debian's kernel config, but explicitly define all configs in our source tree, I double checked)

Starting with kernel 6.12 ZSTD compression is no longer available for ZRAM.
It used to be available by default.

So I would agree with closing this PR for now

CONFIG_ZRAM_WRITEBACK=y
CONFIG_ZRAM_MEMORY_TRACKING=y
CONFIG_ZRAM_DEF_COMP_ZSTD=y

##
## file: drivers/bluetooth/Kconfig
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