On 14/09/2021 20:31, Thomas Hellström wrote:
Just evict unpinned objects to system. For pinned LMEM objects,
make a backup system object and blit the contents to that.
Backup is performed in three steps,
1: Opportunistically evict evictable objects using the gpu blitter.
2: After gt idle, evict evictable objects using the gpu blitter. This will
be modified in an upcoming patch to backup pinned objects that are not used
by the blitter itself.
3: Backup remaining pinned objects using memcpy.
Also move uC suspend to after 2) to make sure we have a functional GuC
during 2) if using GuC submission.
v2:
- Major refactor to make sure gem_exec_suspend@hang-SX subtests work, and
suspend / resume works with a slightly modified GuC submission enabling
patch series.
v3:
- Fix a potential use-after-free (Matthew Auld)
- Use i915_gem_object_create_shmem() instead of
i915_gem_object_create_region (Matthew Auld)
- Minor simplifications (Matthew Auld)
- Fix up kerneldoc for i195_ttm_restore_region().
- Final lmem_suspend() call moved to i915_gem_backup_suspend from
i915_gem_suspend_late, since the latter gets called at driver unload
and we don't unnecessarily want to run it at that time.
Signed-off-by: Thomas Hellström <thomas.hellst...@linux.intel.com>
<snip>
+
+static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
+ struct drm_i915_gem_object *obj)
+{
+ struct i915_gem_ttm_pm_apply *pm_apply =
+ container_of(apply, typeof(*pm_apply), base);
+ struct drm_i915_gem_object *backup = obj->ttm.backup;
+ struct ttm_buffer_object *backup_bo = i915_gem_to_ttm(backup);
+ struct ttm_operation_ctx ctx = {};
+ int err;
+
+ if (!backup)
+ return 0;
+
+ if (!pm_apply->allow_gpu && (obj->flags & I915_BO_ALLOC_USER))
+ return 0;
Hmm, do we ever hit this? I would presume anything that userspace
directly allocated in lmem can be kicked out with ttm_bo_validate(sys)
i.e backup == NULL?
+
+ err = i915_gem_object_lock(backup, apply->ww);
+ if (err)
+ return err;
+
+ /* Content may have been swapped. */
+ err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
+ if (!err) {
+ err = i915_gem_obj_copy_ttm(obj, backup, pm_apply->allow_gpu,
+ false);
+ GEM_WARN_ON(err);
+
+ obj->ttm.backup = NULL;
+ err = 0;
+ }
+
+ i915_gem_ww_unlock_single(backup);
+
+ if (!err)
+ i915_gem_object_put(backup);
+
+ return err;
+}
+
