• Mike Snitzer's avatar
    dm cache: switch the "default" cache replacement policy from mq to smq · bccab6a0
    Mike Snitzer authored
    The Stochastic multiqueue (SMQ) policy (vs MQ) offers the promise of
    less memory utilization, improved performance and increased adaptability
    in the face of changing workloads.  SMQ also does not have any
    cumbersome tuning knobs.
    
    Users may switch from "mq" to "smq" simply by appropriately reloading a
    DM table that is using the cache target.  Doing so will cause all of the
    mq policy's hints to be dropped.  Also, performance of the cache may
    degrade slightly until smq recalculates the origin device's hotspots
    that should be cached.
    
    In the future the "mq" policy will just silently make use of "smq" and
    the mq code will be removed.
    Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
    Acked-by: default avatarJoe Thornber <ejt@redhat.com>
    bccab6a0
cache-policies.txt 6.56 KB