drm/i915: Use partial view in mmap fault handler
Use partial view for huge BOs (bigger than half the mappable aperture)
in fault handler so that they can be accessed withough trying to make
room for them by evicting other objects.
v2:
- Only use partial views in the case where early rejection was
previously done.
- Account variable type changes from previous reroll.
v3:
- Add a comment about overwriting existing page entries.
(Tvrtko Ursulin)
- Whitespace fixes.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 04d18bc..b45f93b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1635,6 +1635,7 @@
struct drm_i915_gem_object *obj = to_intel_bo(vma->vm_private_data);
struct drm_device *dev = obj->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
+ struct i915_ggtt_view view = i915_ggtt_view_normal;
pgoff_t page_offset;
unsigned long pfn;
int ret = 0;
@@ -1667,8 +1668,21 @@
goto unlock;
}
- /* Now bind it into the GTT if needed */
- ret = i915_gem_obj_ggtt_pin(obj, 0, PIN_MAPPABLE);
+ /* Use a partial view if the object is bigger than the aperture. */
+ if (obj->base.size >= dev_priv->gtt.mappable_end) {
+ static const unsigned int chunk_size = 256; // 1 MiB
+ memset(&view, 0, sizeof(view));
+ view.type = I915_GGTT_VIEW_PARTIAL;
+ view.params.partial.offset = rounddown(page_offset, chunk_size);
+ view.params.partial.size =
+ min_t(unsigned int,
+ chunk_size,
+ (vma->vm_end - vma->vm_start)/PAGE_SIZE -
+ view.params.partial.offset);
+ }
+
+ /* Now pin it into the GTT if needed */
+ ret = i915_gem_object_ggtt_pin(obj, &view, 0, PIN_MAPPABLE);
if (ret)
goto unlock;
@@ -1681,30 +1695,50 @@
goto unpin;
/* Finally, remap it using the new GTT offset */
- pfn = dev_priv->gtt.mappable_base + i915_gem_obj_ggtt_offset(obj);
+ pfn = dev_priv->gtt.mappable_base +
+ i915_gem_obj_ggtt_offset_view(obj, &view);
pfn >>= PAGE_SHIFT;
- if (!obj->fault_mappable) {
- unsigned long size = min_t(unsigned long,
- vma->vm_end - vma->vm_start,
- obj->base.size);
- int i;
+ if (unlikely(view.type == I915_GGTT_VIEW_PARTIAL)) {
+ /* 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).
+ */
+ unsigned long base = vma->vm_start +
+ (view.params.partial.offset << PAGE_SHIFT);
+ unsigned int i;
- for (i = 0; i < size >> PAGE_SHIFT; i++) {
- ret = vm_insert_pfn(vma,
- (unsigned long)vma->vm_start + i * PAGE_SIZE,
- pfn + i);
+ for (i = 0; i < view.params.partial.size; i++) {
+ ret = vm_insert_pfn(vma, base + i * PAGE_SIZE, pfn + i);
if (ret)
break;
}
obj->fault_mappable = true;
- } else
- ret = vm_insert_pfn(vma,
- (unsigned long)vmf->virtual_address,
- pfn + page_offset);
+ } else {
+ if (!obj->fault_mappable) {
+ unsigned long size = min_t(unsigned long,
+ vma->vm_end - vma->vm_start,
+ obj->base.size);
+ int i;
+
+ for (i = 0; i < size >> PAGE_SHIFT; i++) {
+ ret = vm_insert_pfn(vma,
+ (unsigned long)vma->vm_start + i * PAGE_SIZE,
+ pfn + i);
+ if (ret)
+ break;
+ }
+
+ obj->fault_mappable = true;
+ } else
+ ret = vm_insert_pfn(vma,
+ (unsigned long)vmf->virtual_address,
+ pfn + page_offset);
+ }
unpin:
- i915_gem_object_ggtt_unpin(obj);
+ i915_gem_object_ggtt_unpin_view(obj, &view);
unlock:
mutex_unlock(&dev->struct_mutex);
out:
@@ -1897,11 +1931,6 @@
goto unlock;
}
- if (obj->base.size > dev_priv->gtt.mappable_end) {
- ret = -E2BIG;
- goto out;
- }
-
if (obj->madv != I915_MADV_WILLNEED) {
DRM_DEBUG("Attempting to mmap a purgeable buffer\n");
ret = -EFAULT;