On Mon, Dec 03, 2012 at 04:30:59PM +0000, Chris Wilson wrote:
> On a machine with bit17 swizzling, we need to store the bit17 of the
> physical page address in put-pages. This requires a memory allocation,
> on average less than a page, which may be difficult to satisfy is the
> request to put-pages is on behalf of the shrinker. We could allow that
> allocation to pull from the reserved memory pools, but it seems much
> safer to preallocate the array for tiled objects on affected machines.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_gem_tiling.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
> index 8e59bb5..140ef6b 100644
> --- a/drivers/gpu/drm/i915/i915_gem_tiling.c
> +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
> @@ -351,6 +351,20 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
> /* we have to maintain this existing ABI... */
> args->stride = obj->stride;
> args->tiling_mode = obj->tiling_mode;
> +
> + /* Try to preallocate memory required to save swizzling on put-pages */
> + if (dev_priv->mm.bit_6_swizzle_x == I915_BIT_6_SWIZZLE_9_10_17) {
> + if (obj->tiling_mode) {
i915_gem_object_needs_bit17_swizzle not suitable?
-Daniel
> + if (obj->bit_17 == NULL) {
> + obj->bit_17 = kmalloc(BITS_TO_LONGS(obj->base.size >> PAGE_SHIFT) *
> + sizeof(long), GFP_KERNEL);
> + }
> + } else {
> + kfree(obj->bit_17);
> + obj->bit_17 = NULL;
> + }
> + }
> +
> drm_gem_object_unreference(&obj->base);
> mutex_unlock(&dev->struct_mutex);
>
> --
> 1.7.10.4
>
> _______________________________________________
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> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
