zswap compressors

Thomas Krichel krichel at openlib.org
Tue Nov 26 10:35:48 EST 2013


  I have two issues with zswap.

  I am running 3.11.0-13-generic #20~precise2-Ubuntu. The zswap doc
  says that I can run a custom compessor and suggests, as an example
  in the doc to use, for example, zswap.compressor=deflate as a kernel
  option. But when I do that dmesg says "zswap: deflate compressor not
  available" and send me back to the default lzo compressor. Trying
  lz4 gets the same note. Is this a bug or a feature, and where should
  this be reported to?

  I wonder why the default compressor is lzo. I understand that,
  roughly, lz4 would achieve roughly the same compression and takes
  roughly the same effort to compress, but decompresses much
  faster. If my understanding is correct, a compressed page is likely
  to be decompressed several times while it stays in the pool.  I
  therefore suspect that lz4 it would be a better compressor for zswap
  than lzo. Am I way off base here?



  Thomas Krichel                  http://openlib.org/home/krichel

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