On Wed, Jul 15, 2015 at 03:41:49PM +0000, Daniel, Thomas wrote: > > -----Original Message----- > > From: Chris Wilson [mailto:chris@xxxxxxxxxxxxxxxxxx] > > Sent: Wednesday, July 15, 2015 4:06 PM > > To: Goel, Akash > > Cc: Daniel, Thomas; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Belgaumkar, Vinay; > > Winiarski, Michal; Zou, Nanhai > > Subject: Re: [PATCH v4] drm/i915: Add soft-pinning API for execbuffer > > > > On Wed, Jul 15, 2015 at 08:25:23PM +0530, Goel, Akash wrote: > > > >>+int > > > >>+i915_gem_evict_for_vma(struct i915_vma *target) > > > >>+{ > > > >>+ struct drm_mm_node *node, *next; > > > >>+ > > > >>+ list_for_each_entry_safe(node, next, > > > >>+ &target->vm->mm.head_node.node_list, > > > >>+ node_list) { > > > >>+ struct i915_vma *vma; > > > >>+ int ret; > > > >>+ > > > >>+ if (node->start + node->size <= target->node.start) > > > >>+ continue; > > > >>+ if (node->start >= target->node.start + target->node.size) > > > >>+ break; > > > >>+ > > > >>+ vma = container_of(node, typeof(*vma), node); > > > >>+ > > > >>+ if (vma->pin_count) { > > > >>+ /* We may need to evict a buffer in the same batch */ > > > >>+ if (!vma->exec_entry) > > > >>+ return -EBUSY; > > > >>+ > > > >>+ if (vma->exec_entry->flags & EXEC_OBJECT_PINNED) > > > >>+ /* Overlapping fixed objects in the same batch > > > >>*/ > > > >>+ return -EINVAL; > > > >>+ > > > >>+ return -ENOSPC; > > > > > > Can we actually hit this condition, considering the soft pinned > > > objects are now on the front side of 'eb->vmas' list ? > > > If we do encounter such a case, it probably means that the > > > overlapping object is already pinned from some other path. > > > > Note that softpinned objects are only first on the second pass through > > the reservation. > Eh? I modified i915_gem_execbuffer_reserve() to always put the softpinned vmas first so they should never collide with objects in the same execbuff. That would be a severe performance penalty for the usual case where we only have to run once through the list. > This contains special stuff which I don't have visibility of (mm.interval_tree, vma.active). Yes. I mentioned that using softpin introduced some perf regressions. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
