• Andrew Morton's avatar
    [PATCH] ext3_readdir: use generic readahead · d8733c29
    Andrew Morton authored
    
    
    Linus points out that ext3_readdir's readahead only cuts in when
    ext3_readdir() is operating at the very start of the directory.  So for large
    directories we end up performing no readahead at all and we suck.
    
    So take it all out and use the core VM's page_cache_readahead().  This means
    that ext3 directory reads will use all of readahead's dynamic sizing goop.
    
    Note that we're using the directory's filp->f_ra to hold the readahead state,
    but readahead is actually being performed against the underlying blockdev's
    address_space.  Fortunately the readahead code is all set up to handle this.
    
    Tested with printk.  It works.  I was struggling to find a real workload which
    actually cared.
    
    (The patch also exports page_cache_readahead() to GPL modules)
    
    Cc: "Stephen C. Tweedie" <sct@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    d8733c29