add support for zswap and ksmtuned
This change add a new lib/host-mem file and moves the existing
ksm support to a new configure_ksm function.
Additional support for ksmtuned is added with a new flag
"ENABLE_KSMTUNED" which defaults to true.
This change also adds support for zswap. zswap is disabled
by default. When enabled on ubuntu lz4 will
be used as the default compressor and z3fold as the zpool.
On non debian distros the compressor and zpool are not set.
The default values should result in very low overhead although
the zstd compressor may provide better overall performance in ci
or with slow io due to the higher compression ratio.
Additionally memory and network sysctl tunings are optionally applied
to defer writes, prefer swapping and optimise tcp connection
startup and keepalive. The sysctl tunings are disabled by default
The base devstack job has been modifed to enable zram and sysctl
tuning.
Both ksm and zswap are wrapped by a tune_host function
which is now called very early in devstack to ensure
they are configured before any memory/network intensive
operations are executed.
The ci jobs do not enable this functionality by default.
To use this functionaltiy define
ENABLE_SYSCTL_MEM_TUNING: true
ENABLE_SYSCTL_NET_TUNING: true
ENABLE_ZSWAP: true
in the devstack_localrc section of the job vars.
Change-Id: Ia5202d5a9903492a4c18b50ea8d12bd91cc9f135
4 files changed