[Intel-gfx] [PATCH 02/20] drm/i915: Switch to object allocations for page directories

[Chris Wilson]

Quoting Chris Wilson (2020-07-06 21:01:54)
> Overallocation is pita for having to preallocate; since we basically
> have to have at least 2 PD for each level + actual span. For every vma,
> even when bundling the insertions, as we don't know which entries will
> be used until much later. So we almost certainly overallocate 4 PD
> [16KiB system + 16KiB dma] for every single vma. Even a 15 entry stash
> will be quickly exhausted; oh well.

Just a note to self, a pvec[15] is too quickly exhausted and does not
hide the allocation costs.
-Chris