drm/xe/vm: Defer vm rebind until next exec if nothing to execute

If all compute engines of a vm in compute mode are idle,
defer a rebind to the next exec to avoid the VM unnecessarily trying
to make memory resident and compete with other VMs for available
memory space.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c
index 97fd1a3..ea869f2 100644 (file)
--- a/drivers/gpu/drm/xe/xe_exec.c
+++ b/drivers/gpu/drm/xe/xe_exec.c
@@ -364,6 +364,7 @@ retry:
                                     &job->drm.s_fence->finished);
 
        xe_sched_job_push(job);
+       xe_vm_reactivate_rebind(vm);
 
 err_repin:
        if (!xe_vm_no_dma_fences(vm))

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 6cc3204..207d20d 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -226,6 +226,19 @@ static int wait_for_existing_preempt_fences(struct xe_vm *vm)
        return 0;
 }
 
+static bool xe_vm_is_idle(struct xe_vm *vm)
+{
+       struct xe_engine *e;
+
+       xe_vm_assert_held(vm);
+       list_for_each_entry(e, &vm->preempt.engines, compute.link) {
+               if (!xe_engine_is_idle(e))
+                       return false;
+       }
+
+       return true;
+}
+
 static void arm_preempt_fences(struct xe_vm *vm, struct list_head *list)
 {
        struct list_head *link;
@@ -548,6 +561,11 @@ retry:
        if (err)
                goto out_unlock_outer;
 
+       if (xe_vm_is_idle(vm)) {
+               vm->preempt.rebind_deactivated = true;
+               goto out_unlock;
+       }
+
        /* Fresh preempt fences already installed. Everyting is running. */
        if (!preempt_fences_waiting(vm))
                goto out_unlock;

diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
index 3468ed9..748dc16 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -98,6 +98,23 @@ extern struct ttm_device_funcs xe_ttm_funcs;
 
 struct ttm_buffer_object *xe_vm_ttm_bo(struct xe_vm *vm);
 
+/**
+ * xe_vm_reactivate_rebind() - Reactivate the rebind functionality on compute
+ * vms.
+ * @vm: The vm.
+ *
+ * If the rebind functionality on a compute vm was disabled due
+ * to nothing to execute. Reactivate it and run the rebind worker.
+ * This function should be called after submitting a batch to a compute vm.
+ */
+static inline void xe_vm_reactivate_rebind(struct xe_vm *vm)
+{
+       if (xe_vm_in_compute_mode(vm) && vm->preempt.rebind_deactivated) {
+               vm->preempt.rebind_deactivated = false;
+               queue_work(system_unbound_wq, &vm->preempt.rebind_work);
+       }
+}
+
 static inline bool xe_vma_is_userptr(struct xe_vma *vma)
 {
        return !vma->bo;

diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index 2a3b911..fada789 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -293,6 +293,11 @@ struct xe_vm {
                struct list_head engines;
                /** @num_engines: number user engines attached to this VM */
                int num_engines;
+               /**
+                * @rebind_deactivated: Whether rebind has been temporarily deactivated
+                * due to no work available. Protected by the vm resv.
+                */
+               bool rebind_deactivated;
                /**
                 * @rebind_work: worker to rebind invalidated userptrs / evicted
                 * BOs