• Daniel Vetter's avatar
    drm/i915: Update write_domains on active list after flush. · 99fcb766
    Daniel Vetter authored
    Before changing the status of a buffer with a pending write we will await
    upon a new flush for that buffer. So we can take advantage of any flushes
    posted whilst the buffer is active and pending processing by the GPU, by
    clearing its write_domain and updating its last_rendering_seqno -- thus
    saving a potential flush in deep queues and improves flushing behaviour
    upon eviction for both GTT space and fences.
    
    In order to reduce the time spent searching the active list for matching
    write_domains, we move those to a separate list whose elements are
    the buffers belong to the active/flushing list with pending writes.
    
    Orignal patch by Chris Wilson <chris@chris-wilson.co.uk>, forward-ported
    by me.
    
    In addition to better performance, this also fixes a real bug. Before
    this changes, i915_gem_evict_everything didn't work as advertised. When
    the gpu was actually busy and processing request, the flush and subsequent
    wait would not move active and dirty buffers to the inactive list, but
    just to the flushing list. Which triggered the BUG_ON at the end of this
    function. With the more tight dirty buffer tracking, all currently busy and
    dirty buffers get moved to the inactive list by one i915_gem_flush operation.
    
    I've left the BUG_ON I've used to prove this in there.
    
    References:
      Bug 25911 - 2.10.0 causes kernel oops and system hangs
      http://bugs.freedesktop.org/show_bug.cgi?id=25911
    
      Bug 26101 - [i915] xf86-video-intel 2.10.0 (and git) triggers kernel oops
                  within seconds after login
      http://bugs.freedesktop.org/show_bug.cgi?id=26101Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Tested-by: default avatarAdam Lantos <hege@playma.org>
    Cc: stable@kernel.org
    Signed-off-by: default avatarEric Anholt <eric@anholt.net>
    99fcb766
i915_drv.h 32.4 KB