On 10/10/2016 23:27, Chris Wilson wrote:
commit 1625e7e549c5 ("drm/i915: make compact dma scatter lists creation work with SWIOTLB backend") took a heavy handed approach to undo the scatterlist compaction in the face of SWIOTLB. (The compaction hit a bug whereby we tried to pass a segment larger than SWIOTLB could handle.) We can be a little more intelligent and try compacting the scatterlist up to the maximum SWIOTLB segment size (when using SWIOTLB).v2: Tidy sg_mark_end() and cpp Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> CC: Imre Deak <imre.d...@intel.com> CC: Daniel Vetter <daniel.vet...@ffwll.ch> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> Cc: Tvrtko Ursulin <tvrtko.ursu...@linux.intel.com> --- drivers/gpu/drm/i915/i915_gem.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index dff8d05d80ee..50fd611926cb 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2201,6 +2201,15 @@ unlock: mutex_unlock(&obj->mm.lock); }+static unsigned long swiotlb_max_size(void)+{ +#if IS_ENABLED(CONFIG_SWIOTLB) + return swiotlb_nr_tbl() << IO_TLB_SHIFT; +#else + return 0; +#endif +} + static struct sg_table * i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj) { @@ -2212,6 +2221,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj) struct sgt_iter sgt_iter; struct page *page; unsigned long last_pfn = 0; /* suppress gcc warning */ + unsigned long max_segment; int ret; gfp_t gfp;@@ -2222,6 +2232,10 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)GEM_BUG_ON(obj->base.read_domains & I915_GEM_GPU_DOMAINS); GEM_BUG_ON(obj->base.write_domain & I915_GEM_GPU_DOMAINS);+ max_segment = swiotlb_max_size();+ if (!max_segment) + max_segment = obj->base.size; + st = kmalloc(sizeof(*st), GFP_KERNEL); if (st == NULL) return ERR_PTR(-ENOMEM); @@ -2263,15 +2277,9 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj) goto err_pages; } } -#ifdef CONFIG_SWIOTLB - if (swiotlb_nr_tbl()) { - st->nents++; - sg_set_page(sg, page, PAGE_SIZE, 0); - sg = sg_next(sg); - continue; - } -#endif - if (!i || page_to_pfn(page) != last_pfn + 1) { + if (!i || + sg->length >= max_segment || + page_to_pfn(page) != last_pfn + 1) { if (i) sg = sg_next(sg); st->nents++; @@ -2284,9 +2292,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj) /* Check that the i965g/gm workaround works. */ WARN_ON((gfp & __GFP_DMA32) && (last_pfn >= 0x00100000UL)); } -#ifdef CONFIG_SWIOTLB - if (!swiotlb_nr_tbl()) -#endif + if (sg) /* loop terminated early; short sg table */ sg_mark_end(sg);ret = i915_gem_gtt_prepare_pages(obj, st);
Reviewed-by: Tvrtko Ursulin <tvrtko.ursu...@intel.com> Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
