• C
    drm/i915: Always mark the object as dirty when used by the GPU · 51bc1404
    Chris Wilson 提交于
    There have been many hard to track down bugs whereby userspace forgot to
    flag a write buffer and then cause graphics corruption or a hung GPU
    when that buffer was later purged under memory pressure (as the buffer
    appeared clean, its pages would have been evicted rather than preserved
    and any changes more recent than in the backing storage would be lost).
    In retrospect this is a rare optimisation against memory pressure,
    already the slow path. If we always mark the buffer as dirty when
    accessed by the GPU, anything not used can still be evicted cheaply
    (ideal behaviour for mark-and-sweep eviction) but we do not run the risk
    of corruption. For correct read serialisation, userspace still has to
    notify when the GPU writes to an object. However, there are certain
    situations under which userspace may wish to tell white lies to the
    kernel...
    Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Cc: Kristian Høgsberg <krh@bitplanet.net>
    Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
    Cc: "Goel, Akash" <akash.goel@intel.co>
    Cc: Michał Winiarski <michal.winiarski@intel.com>
    Cc: stable@vger.kernel.org
    Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
    Signed-off-by: NJani Nikula <jani.nikula@intel.com>
    51bc1404
i915_gem_execbuffer.c 49.0 KB