[00/14] zram: convert to custom comp API and allow algorithms configuration

Message

Sergey Senozhatsky May 3, 2024, 9:17 a.m. UTC

This patch set moves zram from crypto API to a custom compression
API which allows us to tune and configure compression algorithms,
something that crypto API, unfortunately, doesn't support. Basically,
this seroes brings back the bits of comp "backend" code that we had
many years ago. This means that if we want zram to support new
compression algorithms we need to implement corresponding backends.

	Currently, zram supports a pretty decent number of comp backends:
lzo, lzorle, lz4, lz4hc, deflate, zstd

	At this point we handle 2 parameters: a compression level and
a pre-trained compression dictionary. Which seems like a good enough
start. The list will be extended in the future.

Examples:

- changes default compression level
	echo "algo=zstd level=11" > /sys/block/zram0/comp_algorithm

- passes path to a pre-trained dictionary
	echo "algo=zstd dict=/etc/dictionary" > /sys/block/zram0/comp_algorithm

TEST
====

using default zstd
/sys/block/zram0/mm_stat
1750315008 504602831 514256896        0 514256896        1        0    34204    34204

using zstd level=7 dict=/etc/dictionary
/sys/block/zram0/mm_stat
1750310912 432540606 441712640        0 441712640        1        0    34187    34187

Sergey Senozhatsky (14):
  zram: move from crypto API to custom comp backends API
  zram: add lzo and lzorle compression backends support
  zram: add lz4 compression backend support
  zram: add lz4hc compression backend support
  zram: add zstd compression backend support
  zram: pass estimated src size hint to zstd
  zram: add zlib compression backend support
  zram: check that backends array has at least one backend
  zram: introduce zcomp_config structure
  zram: extend comp_algorithm attr write handling
  zram: support compression level comp config
  zram: add support for dict comp config
  zram: add dictionary support to zstd backend
  Documentation/zram: add documentation for algorithm parameters

 Documentation/admin-guide/blockdev/zram.rst |  38 ++++-
 drivers/block/zram/Kconfig                  |  69 ++++++--
 drivers/block/zram/Makefile                 |   7 +
 drivers/block/zram/backend_deflate.c        | 133 +++++++++++++++
 drivers/block/zram/backend_deflate.h        |  10 ++
 drivers/block/zram/backend_lz4.c            |  47 ++++++
 drivers/block/zram/backend_lz4.h            |  10 ++
 drivers/block/zram/backend_lz4hc.c          |  74 +++++++++
 drivers/block/zram/backend_lz4hc.h          |  10 ++
 drivers/block/zram/backend_lzo.c            |  44 +++++
 drivers/block/zram/backend_lzo.h            |  10 ++
 drivers/block/zram/backend_lzorle.c         |  44 +++++
 drivers/block/zram/backend_lzorle.h         |  10 ++
 drivers/block/zram/backend_zstd.c           | 174 ++++++++++++++++++++
 drivers/block/zram/backend_zstd.h           |  10 ++
 drivers/block/zram/zcomp.c                  | 145 ++++++++--------
 drivers/block/zram/zcomp.h                  |  38 ++++-
 drivers/block/zram/zram_drv.c               | 110 ++++++++++++-
 drivers/block/zram/zram_drv.h               |   1 +
 19 files changed, 870 insertions(+), 114 deletions(-)
 create mode 100644 drivers/block/zram/backend_deflate.c
 create mode 100644 drivers/block/zram/backend_deflate.h
 create mode 100644 drivers/block/zram/backend_lz4.c
 create mode 100644 drivers/block/zram/backend_lz4.h
 create mode 100644 drivers/block/zram/backend_lz4hc.c
 create mode 100644 drivers/block/zram/backend_lz4hc.h
 create mode 100644 drivers/block/zram/backend_lzo.c
 create mode 100644 drivers/block/zram/backend_lzo.h
 create mode 100644 drivers/block/zram/backend_lzorle.c
 create mode 100644 drivers/block/zram/backend_lzorle.h
 create mode 100644 drivers/block/zram/backend_zstd.c
 create mode 100644 drivers/block/zram/backend_zstd.h