drm/xe: Convert to USM lock to rwsem

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

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Himal 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 1378c633a3fbfeb344c486ffda0e920a21e62712)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 74e593c..fb7ac06 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -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);
 

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 24c8c2d..00e370d 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -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 */

diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c
index 00af059..5c3af2b 100644 (file)
--- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
@@ -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;
 

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 7acd5fc..a3d7cb7 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -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;