drm/i915: Use remap_io_mapping() to prefault all PTE in a single pass
Very old numbers indicate this is a 66% improvement when remapping the
entire object for fence contention - due to the elimination of
track_pfn_insert and its strcmp.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Testcase: igt/gem_fence_upload/performance
Testcase: igt/gem_mmap_gtt
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160819155428.1670-6-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5398af7..04607d4 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1705,7 +1705,6 @@
bool write = !!(vmf->flags & FAULT_FLAG_WRITE);
struct i915_vma *vma;
pgoff_t page_offset;
- unsigned long pfn;
unsigned int flags;
int ret;
@@ -1790,48 +1789,13 @@
goto err_unpin;
/* Finally, remap it using the new GTT offset */
- pfn = ggtt->mappable_base + i915_ggtt_offset(vma);
- pfn >>= PAGE_SHIFT;
-
- if (vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL) {
- if (!obj->fault_mappable) {
- unsigned long size =
- min_t(unsigned long,
- area->vm_end - area->vm_start,
- obj->base.size) >> PAGE_SHIFT;
- unsigned long base = area->vm_start;
- int i;
-
- for (i = 0; i < size; i++) {
- ret = vm_insert_pfn(area,
- base + i * PAGE_SIZE,
- pfn + i);
- if (ret)
- break;
- }
- } else
- ret = vm_insert_pfn(area,
- (unsigned long)vmf->virtual_address,
- pfn + page_offset);
- } else {
- /* Overriding existing pages in partial view does not cause
- * us any trouble as TLBs are still valid because the fault
- * is due to userspace losing part of the mapping or never
- * having accessed it before (at this partials' range).
- */
- const struct i915_ggtt_view *view = &vma->ggtt_view;
- unsigned long base = area->vm_start +
- (view->params.partial.offset << PAGE_SHIFT);
- unsigned int i;
-
- for (i = 0; i < view->params.partial.size; i++) {
- ret = vm_insert_pfn(area,
- base + i * PAGE_SIZE,
- pfn + i);
- if (ret)
- break;
- }
- }
+ ret = remap_io_mapping(area,
+ area->vm_start + (vma->ggtt_view.params.partial.offset << PAGE_SHIFT),
+ (ggtt->mappable_base + vma->node.start) >> PAGE_SHIFT,
+ min_t(u64, vma->size, area->vm_end - area->vm_start),
+ &ggtt->mappable);
+ if (ret)
+ goto err_unpin;
obj->fault_mappable = true;
err_unpin: