• Dave Chinner's avatar
    superblock: introduce per-sb cache shrinker infrastructure · b0d40c92
    Dave Chinner authored
    With context based shrinkers, we can implement a per-superblock
    shrinker that shrinks the caches attached to the superblock. We
    currently have global shrinkers for the inode and dentry caches that
    split up into per-superblock operations via a coarse proportioning
    method that does not batch very well.  The global shrinkers also
    have a dependency - dentries pin inodes - so we have to be very
    careful about how we register the global shrinkers so that the
    implicit call order is always correct.
    
    With a per-sb shrinker callout, we can encode this dependency
    directly into the per-sb shrinker, hence avoiding the need for
    strictly ordering shrinker registrations. We also have no need for
    any proportioning code for the shrinker subsystem already provides
    this functionality across all shrinkers. Allowing the shrinker to
    operate on a single superblock at a time means that we do less
    superblock list traversals and locking and reclaim should batch more
    effectively. This should result in less CPU overhead for reclaim and
    potentially faster reclaim of items from each filesystem.
    Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    b0d40c92
fs.h 88.6 KB