On 10/13/23 13:38, Thomas Hellström wrote:
On Mon, 2023-10-09 at 01:32 +0200, Danilo Krummrich wrote:Provide a common dma-resv for GEM objects not being used outside of this GPU-VM. This is used in a subsequent patch to generalize dma-resv, external and evicted object handling and GEM validation. Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx> --- drivers/gpu/drm/drm_gpuvm.c | 56 +++++++++++++++++++++++++- drivers/gpu/drm/nouveau/nouveau_uvmm.c | 13 +++++- include/drm/drm_gpuvm.h | 35 +++++++++++++++- 3 files changed, 99 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c index 02ecb45a2544..ebda9d594165 100644 --- a/drivers/gpu/drm/drm_gpuvm.c +++ b/drivers/gpu/drm/drm_gpuvm.c @@ -61,6 +61,15 @@ * contained within struct drm_gpuva already. Hence, for inserting &drm_gpuva * entries from within dma-fence signalling critical sections it is enough to * pre-allocate the &drm_gpuva structures. + * + * &drm_gem_objects which are private to a single VM can share a common + * &dma_resv in order to improve locking efficiency (e.g. with &drm_exec). + * For this purpose drivers must pass a &drm_gem_object to drm_gpuvm_init(), in + * the following called 'root object', which serves as the containerNit: Perhaps resv object altough it might typically be the root page- table object, that doesn't have any meaning to drm_gpuvm, which uses it solely as a container for the resv?
With "root" I didn't want to refer to the object representing the root page-table object, but being *the* object every other (internal) object needs to keep a reference to. Maybe I should be more explicit here and say that drivers need to make sure every internal object requires a reference to take a reference to this root object.
of the + * GPUVM's shared &dma_resv. This root object can be a driver specific + * &drm_gem_object, such as the &drm_gem_object containing the root page table, + * but it can also be a 'dummy' object, which can be allocated with + * drm_gpuvm_root_object_alloc(). *//**@@ -652,9 +661,47 @@ drm_gpuvm_range_valid(struct drm_gpuvm *gpuvm, !drm_gpuvm_in_kernel_node(gpuvm, addr, range); }+static void+drm_gpuvm_gem_object_free(struct drm_gem_object *obj) +{ + drm_gem_object_release(obj); + kfree(obj); +} + +static const struct drm_gem_object_funcs drm_gpuvm_object_funcs = { + .free = drm_gpuvm_gem_object_free, +}; + +/** + * drm_gpuvm_root_object_alloc() - allocate a dummy &drm_gem_object + * @drm: the drivers &drm_device + * + * Allocates a dummy &drm_gem_object which can be passed to drm_gpuvm_init() in + * order to serve as root GEM object providing the &drm_resv shared across + * &drm_gem_objects local to a single GPUVM. + * + * Returns: the &drm_gem_object on success, NULL on failure + */ +struct drm_gem_object * +drm_gpuvm_root_object_alloc(struct drm_device *drm) +{ + struct drm_gem_object *obj; + + obj = kzalloc(sizeof(*obj), GFP_KERNEL); + if (!obj) + return NULL; + + obj->funcs = &drm_gpuvm_object_funcs; + drm_gem_private_object_init(drm, obj, 0); + + return obj; +} +EXPORT_SYMBOL_GPL(drm_gpuvm_root_object_alloc); + /** * drm_gpuvm_init() - initialize a &drm_gpuvm * @gpuvm: pointer to the &drm_gpuvm to initialize + * @r_obj: the root &drm_gem_object providing the GPUVM's common &dma_resv * @name: the name of the GPU VA space * @start_offset: the start offset of the GPU VA space * @range: the size of the GPU VA space @@ -668,7 +715,7 @@ drm_gpuvm_range_valid(struct drm_gpuvm *gpuvm, * &name is expected to be managed by the surrounding driver structures. */ void -drm_gpuvm_init(struct drm_gpuvm *gpuvm, +drm_gpuvm_init(struct drm_gpuvm *gpuvm, struct drm_gem_object *r_obj, const char *name, u64 start_offset, u64 range, u64 reserve_offset, u64 reserve_range, @@ -683,6 +730,9 @@ drm_gpuvm_init(struct drm_gpuvm *gpuvm,gpuvm->name = name ? name : "unknown";gpuvm->ops = ops; + gpuvm->r_obj = r_obj; + + drm_gem_object_get(r_obj);memset(&gpuvm->kernel_alloc_node, 0, sizeof(structdrm_gpuva));@@ -713,7 +763,9 @@ drm_gpuvm_destroy(struct drm_gpuvm *gpuvm)__drm_gpuva_remove(&gpuvm->kernel_alloc_node);WARN(!RB_EMPTY_ROOT(&gpuvm->rb.tree.rb_root),- "GPUVA tree is not empty, potentially leaking memory."); + "GPUVA tree is not empty, potentially leaking memory.\n");Should we cache the drm device in struct drm_gpuvm and use drm_warn() here instead of WARN?
I'd guess the additional backtrace of WARN() isn't overly useful in this case. However, it might be a bit more obvious in dmesg due to its verboseness. Not a strong opinion on that, though.
+ + drm_gem_object_put(gpuvm->r_obj); } EXPORT_SYMBOL_GPL(drm_gpuvm_destroy);diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.cb/drivers/gpu/drm/nouveau/nouveau_uvmm.c index 5cf892c50f43..4dea847ef989 100644 --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c @@ -1808,8 +1808,9 @@ int nouveau_uvmm_init(struct nouveau_uvmm *uvmm, struct nouveau_cli *cli, u64 kernel_managed_addr, u64 kernel_managed_size) { - int ret; + struct drm_gem_object *r_obj; u64 kernel_managed_end = kernel_managed_addr + kernel_managed_size; + int ret;mutex_init(&uvmm->mutex);dma_resv_init(&uvmm->resv); @@ -1833,14 +1834,22 @@ nouveau_uvmm_init(struct nouveau_uvmm *uvmm, struct nouveau_cli *cli, goto out_unlock; }+ r_obj = drm_gpuvm_root_object_alloc(cli->drm->dev);+ if (!r_obj) { + ret = -ENOMEM; + goto out_unlock; + } + uvmm->kernel_managed_addr = kernel_managed_addr; uvmm->kernel_managed_size = kernel_managed_size;- drm_gpuvm_init(&uvmm->base, cli->name,+ drm_gpuvm_init(&uvmm->base, r_obj, cli->name, NOUVEAU_VA_SPACE_START, NOUVEAU_VA_SPACE_END, kernel_managed_addr, kernel_managed_size, NULL); + /* GPUVM takes care from here on. */ + drm_gem_object_put(r_obj);ret = nvif_vmm_ctor(&cli->mmu, "uvmm",cli->vmm.vmm.object.oclass, RAW, diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h index c7ed6bf441d4..0aec14d8b259 100644 --- a/include/drm/drm_gpuvm.h +++ b/include/drm/drm_gpuvm.h @@ -238,9 +238,15 @@ struct drm_gpuvm { * @ops: &drm_gpuvm_ops providing the split/merge steps to drivers */ const struct drm_gpuvm_ops *ops; + + /** + * @r_obj: Root GEM object; representing the GPUVM's common &dma_resv. + */ + struct drm_gem_object *r_obj; };-void drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name,+void drm_gpuvm_init(struct drm_gpuvm *gpuvm, struct drm_gem_object *r_obj, + const char *name, u64 start_offset, u64 range, u64 reserve_offset, u64 reserve_range, const struct drm_gpuvm_ops *ops); @@ -248,6 +254,33 @@ void drm_gpuvm_destroy(struct drm_gpuvm *gpuvm);bool drm_gpuvm_interval_empty(struct drm_gpuvm *gpuvm, u64 addr, u64range);+struct drm_gem_object *+drm_gpuvm_root_object_alloc(struct drm_device *drm); + +/** + * drm_gpuvm_resv() - returns the &drm_gpuvm's &dma_resv + * @gpuvm__: the &drm_gpuvm + * + * Returns: a pointer to the &drm_gpuvm's shared &dma_resv + */ +#define drm_gpuvm_resv(gpuvm__) ((gpuvm__)->r_obj->resv) + +/** + * drm_gpuvm_resv_obj() - returns the &drm_gem_object holding the &drm_gpuvm's + * &dma_resv + * @gpuvm__: the &drm_gpuvm + * + * Returns: a pointer to the &drm_gem_object holding the &drm_gpuvm's shared + * &dma_resv + */ +#define drm_gpuvm_resv_obj(gpuvm__) ((gpuvm__)->r_obj) + +#define drm_gpuvm_resv_held(gpuvm__) \ + dma_resv_held(drm_gpuvm_resv(gpuvm__)) + +#define drm_gpuvm_resv_assert_held(gpuvm__) \ + dma_resv_assert_held(drm_gpuvm_resv(gpuvm__)) + static inline struct drm_gpuva * __drm_gpuva_next(struct drm_gpuva *va) {Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
