Commit d1ef9671 authored by Matthew Brost's avatar Matthew Brost Committed by Lucas De Marchi
Browse files

drm/xe: Convert to USM lock to rwsem 



Remove contention from GPU fault path for ASID->VM lookup.

Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Reviewed-by: default avatarHimal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240918054436.1971839-1-matthew.brost@intel.com


(cherry picked from commit 1378c633)
Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
parent cb589770

drivers/gpu/drm/xe/xe_device.c

+1 −3
Original line number Diff line number Diff line
@@ -339,9 +339,7 @@ struct xe_device *xe_device_create(struct pci_dev *pdev, 


	init_waitqueue_head(&xe->ufence_wq);



	err = drmm_mutex_init(&xe->drm, &xe->usm.lock);

	if (err)

		goto err;

	init_rwsem(&xe->usm.lock);



	xa_init_flags(&xe->usm.asid_to_vm, XA_FLAGS_ALLOC);

drivers/gpu/drm/xe/xe_device_types.h

+1 −1
Original line number Diff line number Diff line
@@ -369,7 +369,7 @@ struct xe_device { 
		/** @usm.next_asid: next ASID, used to cyclical alloc asids */

		u32 next_asid;

		/** @usm.lock: protects UM state */

		struct mutex lock;

		struct rw_semaphore lock;

	} usm;



	/** @pinned: pinned BO state */

drivers/gpu/drm/xe/xe_gt_pagefault.c

+4 −4
Original line number Diff line number Diff line
@@ -198,13 +198,13 @@ static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf) 
		return -EFAULT;



	/* ASID to VM */

	mutex_lock(&xe->usm.lock);

	down_read(&xe->usm.lock);

	vm = xa_load(&xe->usm.asid_to_vm, pf->asid);

	if (vm && xe_vm_in_fault_mode(vm))

		xe_vm_get(vm);

	else

		vm = NULL;

	mutex_unlock(&xe->usm.lock);

	up_read(&xe->usm.lock);

	if (!vm)

		return -EINVAL;
@@ -549,11 +549,11 @@ static int handle_acc(struct xe_gt *gt, struct acc *acc) 
		return -EINVAL;



	/* ASID to VM */

	mutex_lock(&xe->usm.lock);

	down_read(&xe->usm.lock);

	vm = xa_load(&xe->usm.asid_to_vm, acc->asid);

	if (vm)

		xe_vm_get(vm);

	mutex_unlock(&xe->usm.lock);

	up_read(&xe->usm.lock);

	if (!vm || !xe_vm_in_fault_mode(vm))

		return -EINVAL;

drivers/gpu/drm/xe/xe_vm.c

+4 −4
Original line number Diff line number Diff line
@@ -1613,7 +1613,7 @@ void xe_vm_close_and_put(struct xe_vm *vm) 


	up_write(&vm->lock);



	mutex_lock(&xe->usm.lock);

	down_write(&xe->usm.lock);

	if (vm->usm.asid) {

		void *lookup;
@@ -1623,7 +1623,7 @@ void xe_vm_close_and_put(struct xe_vm *vm) 
		lookup = xa_erase(&xe->usm.asid_to_vm, vm->usm.asid);

		xe_assert(xe, lookup == vm);

	}

	mutex_unlock(&xe->usm.lock);

	up_write(&xe->usm.lock);



	for_each_tile(tile, xe, id)

		xe_range_fence_tree_fini(&vm->rftree[id]);
@@ -1772,11 +1772,11 @@ int xe_vm_create_ioctl(struct drm_device *dev, void *data, 
		goto err_close_and_put;



	if (xe->info.has_asid) {

		mutex_lock(&xe->usm.lock);

		down_write(&xe->usm.lock);

		err = xa_alloc_cyclic(&xe->usm.asid_to_vm, &asid, vm,

				      XA_LIMIT(1, XE_MAX_ASID - 1),

				      &xe->usm.next_asid, GFP_KERNEL);

		mutex_unlock(&xe->usm.lock);

		up_write(&xe->usm.lock);

		if (err < 0)

			goto err_free_id;