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Sirajus Salekin
Asked: 2017-01-29 02:46:08 +0800 CST

enabling lz4 compression in zswap (ie, making zswap more efficient)

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I'm trying to enable LZ4 compression for zswap on Ubuntu 16.04.1 LTS.

My GRUB config:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash elevator=cfq profile zswap.enabled=1 zswap.compressor=lz4 zswap.max_pool_percent=80"

I executed sudo update-grub, and rebooted. But, zswap says compressor lz4 not available, using default lzo. I have liblz4-tool installed. This is the message I get after executing dmesg | grep zswap

[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-59-generic.efi.signed root=UUID=148a9e6d-52db-4678-b11d-ef1e5559b69d ro quiet splash elevator=cfq profile zswap.enabled=1 zswap.compressor=lz4 zswap.max_pool_percent=80 vt.handoff=7
[    0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-59-generic.efi.signed root=UUID=148a9e6d-52db-4678-b11d-ef1e5559b69d ro quiet splash elevator=cfq profile zswap.enabled=1 zswap.compressor=lz4 zswap.max_pool_percent=80 vt.handoff=7
[    0.716485] zswap: compressor lz4 not available, using default lzo
[    0.716493] zswap: loaded using pool lzo/zbud
16.04

1 Answers

  1. Best Answer

    I've found the solution in this Russian Debian Forum. I had to run these extra steps

    sudo su
echo lz4 >> /etc/initramfs-tools/modules
echo lz4_compress >> /etc/initramfs-tools/modules
update-initramfs -u
reboot

    And run dmesg | grep -i zswap, to see

    [    0.715952] zswap: loaded using pool lz4/zbud

    Excited to see how the performance improves.

    edit: I have written my steps in this guide. You can check if you face issues enabling zswap.

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