• Chris Wilson's avatar
    drm/i915: Bump the inactive LRU on set-to-GTT-domain · 8325a09d
    Chris Wilson authored
    
    
    Currently, we only bump the inactive LRU of an object when we bind
    into the GTT for a page-fault. As the object may be used many times
    before its mapping is zapped, we do not mark it as active as
    frequently as we should. Userspace should be calling set-to-GTT-domain
    before each pointer deference (for synchronous access) and so is a
    good place to mark the buffer as active.
    
    Marking the buffer as recently used places it at the end of the
    inactive eviction queue, though still before anything with outstanding
    rendering. This reduces the likelihood of evicting a buffer that is
    going to be used again by the CPU in the near future. This way we can
    hopefully avoid to kick out upload buffers right before we use them on
    the gpu.
    
    Note that we need to check that the object is not active or pinned,
    for otherwise we create havoc on the active/pinned lists, which also
    use obj->mm_list.
    
    The active lists are sorted by and evicted in last GPU rendering
    order, access by the CPU to a still active buffer therefore does not
    affect its eviction ordering. Pinned objects are currently excluded
    from eviction, therefore the only list that we need to bump for GTT
    access by the CPU is the inactive list.
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    [danvet: Added further explanations to the commit message as discussed
    on irc.]
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    8325a09d