Re: [Intel-gfx] [PATCH 03/10] drm/i915: Assume exclusive access to objects inside resume

[Matthew Auld]

On Mon, 19 Aug 2019 at 17:45, Chris Wilson  wrote:
>
> Inside gtt_restore_mappings() we currently take the obj->resv->lock, but
> in the future we need to avoid taking this fs-reclaim tainted lock as we
> need to extend the coverage of the vm->mutex. Take advantage of the
> single-threaded nature of the early resume phase, and do a single
> wbinvd() to flush all the GTT objects en masse.
>
> Signed-off-by: Chris Wilson 
Reviewed-by: Matthew Auld 
___
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

[Intel-gfx] [PATCH 03/10] drm/i915: Assume exclusive access to objects inside resume

[Chris Wilson]

Inside gtt_restore_mappings() we currently take the obj->resv->lock, but
in the future we need to avoid taking this fs-reclaim tainted lock as we
need to extend the coverage of the vm->mutex. Take advantage of the
single-threaded nature of the early resume phase, and do a single
wbinvd() to flush all the GTT objects en masse.

Signed-off-by: Chris Wilson 
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 11 +++
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c 
b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 5413c2ff51a2..e48df11a19fb 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3274,6 +3274,7 @@ void i915_ggtt_disable_guc(struct i915_ggtt *ggtt)
 static void ggtt_restore_mappings(struct i915_ggtt *ggtt)
 {
struct i915_vma *vma, *vn;
+   bool flush = false;
 
intel_gt_check_and_clear_faults(ggtt->vm.gt);
 
@@ -3298,10 +3299,9 @@ static void ggtt_restore_mappings(struct i915_ggtt *ggtt)
WARN_ON(i915_vma_bind(vma,
  obj ? obj->cache_level : 0,
  PIN_UPDATE));
-   if (obj) {
-   i915_gem_object_lock(obj);
-   WARN_ON(i915_gem_object_set_to_gtt_domain(obj, false));
-   i915_gem_object_unlock(obj);
+   if (obj) { /* only used during resume => exclusive access */
+   flush |= fetch_and_zero(>write_domain);
+   obj->read_domains |= I915_GEM_DOMAIN_GTT;
}
 
 lock:
@@ -3312,6 +3312,9 @@ static void ggtt_restore_mappings(struct i915_ggtt *ggtt)
ggtt->invalidate(ggtt);
 
mutex_unlock(>vm.mutex);
+
+   if (flush)
+   wbinvd_on_all_cpus();
 }
 
 void i915_gem_restore_gtt_mappings(struct drm_i915_private *i915)
-- 
2.23.0.rc1

___
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx