While the range notifier is executing, we have the write-side mmu interval seqlock, and mmu_interval_read_retry() is always returning true, which means that if amdgpu_cs_submit grabs the notifier lock during the fence wait, it will retry anyway when checking the userptr validity and block when retrying in mmu_interval_read_begin(). (See the extensive comments in mmu_interval_read_begin())
Hence we can release the notifier lock before the fence wait and avoid a device-wide command submission block during invalidation.
Cc: Christian König christian.koenig@amd.com Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com --- drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c index 4b153daf283d..d3d340a6129c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c @@ -75,9 +75,10 @@ static bool amdgpu_mn_invalidate_gfx(struct mmu_interval_notifier *mni,
mmu_interval_set_seq(mni, cur_seq);
+ mutex_unlock(&adev->notifier_lock); + r = dma_resv_wait_timeout(bo->tbo.base.resv, true, false, MAX_SCHEDULE_TIMEOUT); - mutex_unlock(&adev->notifier_lock); if (r <= 0) DRM_ERROR("(%ld) failed to wait for user bo\n", r); return true;