On 14/10/2016 13:18, Chris Wilson wrote:
We can use the radixtree index of the obj->pages to find the start
position of the desired partial range.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 40 ++++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 2bbbda191e93..b3f341fe77bf 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3584,35 +3584,47 @@ intel_partial_pages(const struct i915_ggtt_view *view,
struct drm_i915_gem_object *obj)
{
struct sg_table *st;
- struct scatterlist *sg;
- struct sg_page_iter obj_sg_iter;
+ struct scatterlist *sg, *iter;
+ unsigned int count = view->params.partial.size;
+ unsigned int offset;
int ret = -ENOMEM;
st = kmalloc(sizeof(*st), GFP_KERNEL);
if (!st)
goto err_st_alloc;
- ret = sg_alloc_table(st, view->params.partial.size, GFP_KERNEL);
+ ret = sg_alloc_table(st, count, GFP_KERNEL);
if (ret)
goto err_sg_alloc;
+ iter = i915_gem_object_get_sg(obj,
+ view->params.partial.offset,
+ &offset);
+ GEM_BUG_ON(!iter);
+
sg = st->sgl;
st->nents = 0;
- for_each_sg_page(obj->pages->sgl, &obj_sg_iter, obj->pages->nents,
- view->params.partial.offset)
- {
- if (st->nents >= view->params.partial.size)
- break;
+ do {
+ unsigned int len;
- sg_set_page(sg, NULL, PAGE_SIZE, 0);
- sg_dma_address(sg) = sg_page_iter_dma_address(&obj_sg_iter);
- sg_dma_len(sg) = PAGE_SIZE;
+ len = min(iter->length - (offset << PAGE_SHIFT),
+ count << PAGE_SHIFT);
+ sg_set_page(sg, NULL, len, 0);
+ sg_dma_address(sg) =
+ sg_dma_address(iter) + (offset << PAGE_SHIFT);
+ sg_dma_len(sg) = len;
- sg = sg_next(sg);
st->nents++;
- }
+ count -= len >> PAGE_SHIFT;
+ if (count == 0) {
+ sg_mark_end(sg);
+ return st;
+ }
- return st;
+ sg = __sg_next(sg);
+ iter = __sg_next(iter);
+ offset = 0;
+ } while (1);
err_sg_alloc:
kfree(st);
Looks OK and I trust you when you say it is faster.
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Regards,
Tvrtko
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