[PATCH] drm/xe: Don't use drm exec locking in SVM pagefaults
Matthew Brost
matthew.brost at intel.com
Tue Jun 3 17:40:12 UTC 2025
Only the VM dma-resv lock is needed in SVM pagefaults so
xe_vm_lock/unlock can be used instead of drm exec. Micro optimization
but should save some CPU cycles in a critical path.
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
drivers/gpu/drm/xe/xe_svm.c | 36 +++++++++++++-----------------------
1 file changed, 13 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index f27fb9b588de..952b75a4264d 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -858,7 +858,6 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
vm->xe->atomic_svm_timeslice_ms : 0,
};
struct xe_svm_range *range;
- struct drm_exec exec;
struct dma_fence *fence;
struct xe_tile *tile = gt_to_tile(gt);
int migrate_try_count = ctx.devmem_only ? 3 : 1;
@@ -933,30 +932,21 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
range_debug(range, "PAGE FAULT - BIND");
retry_bind:
- drm_exec_init(&exec, 0, 0);
- drm_exec_until_all_locked(&exec) {
- err = drm_exec_lock_obj(&exec, vm->gpuvm.r_obj);
- drm_exec_retry_on_contention(&exec);
- if (err) {
- drm_exec_fini(&exec);
- goto err_out;
- }
-
- fence = xe_vm_range_rebind(vm, vma, range, BIT(tile->id));
- if (IS_ERR(fence)) {
- drm_exec_fini(&exec);
- err = PTR_ERR(fence);
- if (err == -EAGAIN) {
- ctx.timeslice_ms <<= 1; /* Double timeslice if we have to retry */
- range_debug(range, "PAGE FAULT - RETRY BIND");
- goto retry;
- }
- if (xe_vm_validate_should_retry(&exec, err, &end))
- goto retry_bind;
- goto err_out;
+ xe_vm_lock(vm, false);
+ fence = xe_vm_range_rebind(vm, vma, range, BIT(tile->id));
+ if (IS_ERR(fence)) {
+ xe_vm_unlock(vm);
+ err = PTR_ERR(fence);
+ if (err == -EAGAIN) {
+ ctx.timeslice_ms <<= 1; /* Double timeslice if we have to retry */
+ range_debug(range, "PAGE FAULT - RETRY BIND");
+ goto retry;
}
+ if (xe_vm_validate_should_retry(NULL, err, &end))
+ goto retry_bind;
+ goto err_out;
}
- drm_exec_fini(&exec);
+ xe_vm_unlock(vm);
dma_fence_wait(fence, false);
dma_fence_put(fence);
--
2.34.1
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