On Wed, Oct 1, 2025 at 5:13 PM Boris Brezillon <[email protected]> wrote: > > On Wed, 1 Oct 2025 16:42:35 +0200 > Alice Ryhl <[email protected]> wrote: > > > On Wed, Oct 1, 2025 at 4:01 PM Danilo Krummrich <[email protected]> wrote: > > > > > > On Wed Oct 1, 2025 at 12:41 PM CEST, Alice Ryhl wrote: > > > > +/* > > > > + * Must be called with GEM mutex held. After releasing GEM mutex, > > > > + * drm_gpuvm_bo_defer_free_unlocked() must be called. > > > > + */ > > > > +static void > > > > +drm_gpuvm_bo_defer_free_locked(struct kref *kref) > > > > +{ > > > > + struct drm_gpuvm_bo *vm_bo = container_of(kref, struct > > > > drm_gpuvm_bo, > > > > + kref); > > > > + struct drm_gpuvm *gpuvm = vm_bo->vm; > > > > + > > > > + if (!drm_gpuvm_resv_protected(gpuvm)) { > > > > + drm_gpuvm_bo_list_del(vm_bo, extobj, true); > > > > + drm_gpuvm_bo_list_del(vm_bo, evict, true); > > > > + } > > > > + > > > > + list_del(&vm_bo->list.entry.gem); > > > > +} > > > > + > > > > +/* > > > > + * GEM mutex must not be held. Called after > > > > drm_gpuvm_bo_defer_free_locked(). > > > > + */ > > > > +static void > > > > +drm_gpuvm_bo_defer_free_unlocked(struct drm_gpuvm_bo *vm_bo) > > > > +{ > > > > + struct drm_gpuvm *gpuvm = vm_bo->vm; > > > > + > > > > + llist_add(&vm_bo->list.entry.bo_defer, &gpuvm->bo_defer); > > > > +} > > > > + > > > > +static void > > > > +drm_gpuvm_bo_defer_free(struct kref *kref) > > > > +{ > > > > + struct drm_gpuvm_bo *vm_bo = container_of(kref, struct > > > > drm_gpuvm_bo, > > > > + kref); > > > > + > > > > + mutex_lock(&vm_bo->obj->gpuva.lock); > > > > + drm_gpuvm_bo_defer_free_locked(kref); > > > > + mutex_unlock(&vm_bo->obj->gpuva.lock); > > > > + > > > > + /* > > > > + * It's important that the GEM stays alive for the duration in > > > > which we > > > > + * hold the mutex, but the instant we add the vm_bo to bo_defer, > > > > + * another thread might call drm_gpuvm_bo_deferred_cleanup() and > > > > put > > > > + * the GEM. Therefore, to avoid kfreeing a mutex we are holding, > > > > we add > > > > + * the vm_bo to bo_defer *after* releasing the GEM's mutex. > > > > + */ > > > > + drm_gpuvm_bo_defer_free_unlocked(vm_bo); > > > > +} > > > > > > So, you're splitting drm_gpuvm_bo_defer_free() into two functions, one > > > doing the > > > work that is required to be called with the gpuva lock held and one that > > > does > > > the work that does not require a lock, which makes perfect sense. > > > > > > However, the naming chosen for the two functions, i.e. > > > drm_gpuvm_bo_defer_free_unlocked() and drm_gpuvm_bo_defer_free_locked() is > > > confusing: > > > > > > What you mean semantically mean is "do part 1 with lock held" and "do > > > part 2 > > > without lock held", but the the chosen names suggest that both functions > > > are > > > identical, with the only difference that one takes the lock internally > > > and the > > > other one requires the caller to take the lock. > > > > > > It's probably better to name them after what they do and not what they're > > > part > > > of. If you prefer the latter, that's fine with me too, but please choose > > > a name > > > that makes this circumstance obvious. > > > > Fair point. Do you have naming suggestions? Otherwise I can name them > > drm_gpuvm_bo_defer_free_part1() and drm_gpuvm_bo_defer_free_part2(). > > :) > > drm_gpuvm_bo_free_deferral_extract_locked() and > drm_gpuvm_bo_free_deferral_enqueue()? Definitely not short names though.
With those names I have to do some additional line breaks. How about: drm_gpuvm_bo_into_zombie() drm_gpuvm_bo_defer_zombie() leaning on the zombie terminology I already added for the drm_gpuvm_bo_is_zombie() function. Alice
