On Tue, 2024-05-28 at 08:51 +0200, Christian König wrote:2) Any contended lock held at loop start is completely encapsulated in the ww transaction and can and will be unlocked when exiting it, so this patch doesn't introduce any additional problems for userptr handling AFAICT.The drm_exec object was intentionally design to not have anything locked at the beginning of the loop. See the discussion I had with Sima around that when pushing the drm_exec object upstream. I would really like to stick with that design and honestly don't see the reason to change that. Contenting on a trylock seem to be much more questionable.The change here is to make sure we *don't* have contention in a trylock, which is otherwise inherent in the current drm_exec design.
My sentence was probably a bit misleading. What I wanted to say is that trylock as first thing in the loop sounds really odd to me.
See the intention of a trylock is to acquire something optional. What we do for the freshly allocated BO and the 'don't try to block with the mmap lock held' case is actually kind something different.
A clean approach would be to to have the BO initialization and backing store allocation steps separated. In this case you don't even need to use trylock here.
And for the VM fault locking case the clean approach would be to tell the drm_exec object of the vm_fault parameters so that this helper can do the drop all locks, drop the mmap lock, acquire the blocking lock and return -EAGAIN.
This has the huge benefit that we not only stop blocking for the faulted BO, but eventually all others which might need to move so that the faulted BO is CPU accessible. I think that this is actually the more problematic case.
What I'm trying to say here is that we end up with the contended lock grabbed at loop start you already conceptually have a conflicting lock held (the we_class::acquire_key). Both these can be resolved.
Yeah, I'm perfectly aware of that. But this is just a shortcoming of lockdep and not a real problem.
During the drm_exec code review we already moved the ww_acquire_init() into the cleanup function so that it's only called at the start of the loop. Background is that we ran into lockdep warnings with that otherwise.
But functionally it would still work if we do this in drm_exec_ini().
3) The need for a fully capable ww transaction helper moving forward. If we need a tool that also does userptr locking, then I think we need to separate that from the ww transaction tool and only pass the latter around to TTM.drm_exec is *not* meant to be a ww_transaction helper. The functionality here is to support drivers in their CS interface and that includes userptr handling as well as a couple of other things.Then if so, I don't think drm_exec is the correct functionality to pass to TTM to resolve the eviction issues, but rather a ww transaction helper that can be used standalone *and* by drm_exec. Now the functionality would be more or less what drm exec is today, but slightly augmented. But then IMHO instead of changing name and more or less replicating what drm_exec is today wouldn't it be a better idea to subclass drm_exec into a full-fledged CS helper at the time when that functionality is indeed added?
Mhm, interesting idea. But it still means that the base object needs to be designed in a way to not prevent the implementation of the subclass.
Christian.
/ThomasRegards, Christian.Thanks, Thomas On Wed, 2024-05-22 at 19:42 +0200, Thomas Hellström wrote:On Wed, 2024-05-22 at 18:52 +0200, Christian König wrote:Am 22.05.24 um 16:32 schrieb Thomas Hellström:On Wed, 2024-05-22 at 07:52 +0200, Christian König wrote:Am 21.05.24 um 09:16 schrieb Thomas Hellström:If contention and backoff occurs during a drm_exec ww transaction, the contended lock is not locked again until the next orinary attempt to lock a dma_resv lock. However, with the introduction of drm_exec_trylock(), that doesn't work, since the locking of the contended lock needs to be a sleeping lock. Neither can we ignore locking the contended lock during a trylock since that would violate at least the ww_mutex annotations. So resolve this by actually locking the contended lock during drm_exec_retry_on_contention(). However, this introduces a new point of failure since locking the contended lock may return - EINTR. Hence drm_exec_retry_on_contention() must take an error parameter and also return a value indicating success.After thinking more about that I have to pretty clearly NAK this.I thought we were beyond upfront NAKing in the first reply :/Well my memory could fail me, but I mentioned concerns on this approach before. I was a bit annoyed seeing that again. But could as well be that my response never got out or that I'm mixing things up.I haven't seen it at least. Last discussion on this I saw was here. I didn't see a follow-up on that. https://lore.kernel.org/dri-devel/953c157bf69df12d831a781f0f638d93717bb044.camel@xxxxxxxxxxxxxxx/It's an intentional design decision to guarantee that at the start of the loop no object is locked. This is because Sima and I wanted to integrate userptr handling into drm_exec as well in the long term.First I agree the interface looks worse with this patch. But I thought generic userptr handling were going to end up as a gpuvm helper (without using GEM objects) as we've discussed previously.We might be talking past each other. That sounds like SVM, e.g. on demand paging. What I mean is pre-faulting during command submission like radeon, amdgpu and i915 do for the userptr handling.Yes, then we're talking about the same thing. We discussed in this thread here, started by Dave. https://lore.kernel.org/dri-devel/CAPM=9twPgn+fpbkig0Vhjt=cJdHQFbNH_Z=sRhSZwuvLKhavbA@xxxxxxxxxxxxxx/ I still think the right place is in drm_gpuvm for this sort of stuff. And I think that's the concluding argument by Sima as well. In any case, If the planned drm_exec development is to be a full execbuf helper, I think we need a capable sub-helper for ONLY the ww transaction locking as well, with support for the various locking primitives. In particular if we're going to be able to port i915 ww transaction locking over. There are more uses of the ww locking transacions than execbuf.For that you need to re-start the whole handling similar to how you need to re-start for the mutex locking when you detect that the page array is stale, the difference is that you are not allowed to hold any resv locks while pre-faulting. That's why it is a requirement that the drm_exec loop starts without any locks held.But wouldn't you need an outer (userptr) loop and an inner (ww_transaction) loop for this? Why would we want to re-validate userptrs on -EDEADLKS?Anyway if still there would be helpers in drm_exec for some other generic userptr solution, those need to be done before the ww_acquire_ctx_init(). The contended locking here is done after, so I can't really see how these would clash.Yes, that indeed was a problem. The ww_acquire_ctx_init() was intentionally moved into drm_exec_cleanup() to partially prevent that issue. I haven't fully figured out how to do handle everything exactly, but at least in principle it can be made work. With this change here it becomes impossible.Still, If we need to come up with another solution, I think it's fair we clearly sort out why.I think we should just document that drm_exec_trylock() can't be used to lock the first BO in the loop and explicitly WARN if that's the case.Unfortunately that's not sufficient for the general use-case. If we want to keep the ttm_bo_vm approach of dropping the mmap lock when there is contention on the bo resv, we need to be able to trylock on first lock.Mhm, why exactly do we still have that dance in the first place? I mean we have sorted out the mmap() and dma_resv() locking order long ago. See dma_resv_lockdep() which is enforcing that.I explained that in my reply here: https://lore.kernel.org/dri-devel/953c157bf69df12d831a781f0f638d93717bb044.camel@xxxxxxxxxxxxxxx/ We shouldn't be holding the mmap lock when waiting for stuff. In particular not while waiting for mutexes that may be blocked by gpu activity.Also bo creation is using trylock but might be able to use a sleeping lock there. But if that sleeping lock triggers an - EDEADLK (DEBUG_WW_MUTEX_SLOWPATH) we have the weird situation of referencing an object that never was fully created as a contending object.I wanted to eliminate that as well by not validating the BO during initialization any more. So bo creation would then be: ttm_bo_init(bo) drm_exec_while_not_all_locked() { drm_exec_prepare_object(bo, 1); ttm_bo_validate(bo); } if (r) ttm_bo_put(bo); return r; I have that on a branch here somewhere prepared, but never got the time to clean it up.Still, bo creation and validation may be part of a ww transaction as well, like page-table bos (Although those are pre-locked so perhaps not a good example). But in the general case, I'm not sure this is sufficient for all use-cases. /ThomasRegards, Christian.So the only really working alternative solution I can see is that drm_exec_trylock simply fails if there is a contended lock and we'd need to live with the weird bo creation situation described above. /ThomasRegards, Christian.Cc: Christian König<christian.koenig@xxxxxxx> Cc: Somalapuram Amaranath<Amaranath.Somalapuram@xxxxxxx> Cc: Matthew Brost<matthew.brost@xxxxxxxxx> Cc:<dri-devel@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Thomas Hellström<thomas.hellstrom@xxxxxxxxxxxxxxx> --- .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 ++++--- -- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 ++-- drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c | 4 +- - drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 8 ++--- drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c | 8 ++--- drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c | 4 +- - drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c | 8 ++--- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 2 +- drivers/gpu/drm/drm_exec.c | 35 ++++++++++++++----- drivers/gpu/drm/drm_gpuvm.c | 8 ++--- drivers/gpu/drm/imagination/pvr_job.c | 2 +- drivers/gpu/drm/msm/msm_gem_submit.c | 2 +- drivers/gpu/drm/nouveau/nouveau_uvmm.c | 2 +- drivers/gpu/drm/tests/drm_exec_test.c | 12 +++---- drivers/gpu/drm/xe/xe_gt_pagefault.c | 4 +- - drivers/gpu/drm/xe/xe_vm.c | 10 +++--- include/drm/drm_exec.h | 23 +++++++++--- 17 files changed, 92 insertions(+), 62 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index e4d4e55c08ad..4a08a692aa1f 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -1152,12 +1152,12 @@ static int reserve_bo_and_vm(struct kgd_mem *mem, drm_exec_init(&ctx->exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); drm_exec_until_all_locked(&ctx->exec) { ret = amdgpu_vm_lock_pd(vm, &ctx->exec, 2); - drm_exec_retry_on_contention(&ctx-exec);+ ret = drm_exec_retry_on_contention(&ctx-exec,ret); if (unlikely(ret)) goto error; ret = drm_exec_prepare_obj(&ctx->exec, &bo-tbo.base, 1);- drm_exec_retry_on_contention(&ctx-exec);+ ret = drm_exec_retry_on_contention(&ctx-exec,ret); if (unlikely(ret)) goto error; } @@ -1199,14 +1199,14 @@ static int reserve_bo_and_cond_vms(struct kgd_mem *mem, ret = amdgpu_vm_lock_pd(entry-bo_va- base.vm,&ctx-exec,2); - drm_exec_retry_on_contention(&ctx-exec);+ ret = drm_exec_retry_on_contention(&ctx-exec, ret);if (unlikely(ret)) goto error; ++ctx->n_vms; } ret = drm_exec_prepare_obj(&ctx->exec, &bo-tbo.base, 1);- drm_exec_retry_on_contention(&ctx-exec);+ ret = drm_exec_retry_on_contention(&ctx-exec,ret); if (unlikely(ret)) goto error; } @@ -2619,7 +2619,7 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info) list_for_each_entry(peer_vm, &process_info-vm_list_head,vm_list_node) { ret = amdgpu_vm_lock_pd(peer_vm, &exec, 2); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); if (unlikely(ret)) goto unreserve_out; } @@ -2631,7 +2631,7 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info) gobj = &mem->bo->tbo.base; ret = drm_exec_prepare_obj(&exec, gobj, 1); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); if (unlikely(ret)) goto unreserve_out; } @@ -2875,7 +2875,7 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu * list_for_each_entry(peer_vm, &process_info-vm_list_head,vm_list_node) { ret = amdgpu_vm_lock_pd(peer_vm, &exec, 2); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); if (unlikely(ret)) { pr_err("Locking VM PD failed, ret: %d\n", ret); goto ttm_reserve_fail; @@ -2891,7 +2891,7 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu * gobj = &mem->bo->tbo.base; ret = drm_exec_prepare_obj(&exec, gobj, 1); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); if (unlikely(ret)) { pr_err("drm_exec_prepare _obj failed, ret: %d\n", ret); goto ttm_reserve_fail; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c index ec888fc6ead8..299e46a6d934 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c @@ -897,7 +897,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p, drm_exec_until_all_locked(&p->exec) { r = amdgpu_vm_lock_pd(&fpriv->vm, &p-exec,1 + p-gang_size);- drm_exec_retry_on_contention(&p->exec); + r = drm_exec_retry_on_contention(&p-exec,r); if (unlikely(r)) goto out_free_user_pages; @@ -905,7 +905,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p, /* One fence for TTM and one for each CS job */ r = drm_exec_prepare_obj(&p-exec,&e-bo- tbo.base,1 + p-gang_size);- drm_exec_retry_on_contention(&p-exec);+ r = drm_exec_retry_on_contention(&p-exec,r); if (unlikely(r)) goto out_free_user_pages; @@ -915,7 +915,7 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p, if (p->uf_bo) { r = drm_exec_prepare_obj(&p-exec,&p-uf_bo->tbo.base,1 + p-gang_size);- drm_exec_retry_on_contention(&p-exec);+ r = drm_exec_retry_on_contention(&p-exec,r); if (unlikely(r)) goto out_free_user_pages; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c index cfdf558b48b6..8b2b86c7a6c5 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c @@ -74,7 +74,7 @@ int amdgpu_map_static_csa(struct amdgpu_device *adev, struct amdgpu_vm *vm, r = amdgpu_vm_lock_pd(vm, &exec, 0); if (likely(!r)) r = drm_exec_lock_obj(&exec, &bo-tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) { DRM_ERROR("failed to reserve CSA,PD BOs: err=%d\n", r); goto error; @@ -114,7 +114,7 @@ int amdgpu_unmap_static_csa(struct amdgpu_device *adev, struct amdgpu_vm *vm, r = amdgpu_vm_lock_pd(vm, &exec, 0); if (likely(!r)) r = drm_exec_lock_obj(&exec, &bo-tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) { DRM_ERROR("failed to reserve CSA,PD BOs: err=%d\n", r); goto error; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c index 67c234bcf89f..17e16c971e21 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c @@ -239,12 +239,12 @@ static void amdgpu_gem_object_close(struct drm_gem_object *obj, drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0); drm_exec_until_all_locked(&exec) { r = drm_exec_prepare_obj(&exec, &bo-tbo.base,1); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto out_unlock; r = amdgpu_vm_lock_pd(vm, &exec, 0); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto out_unlock; } @@ -776,13 +776,13 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data, drm_exec_until_all_locked(&exec) { if (gobj) { r = drm_exec_lock_obj(&exec, gobj); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error; } r = amdgpu_vm_lock_pd(&fpriv->vm, &exec, 2); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c index 5ca5c47ab54e..1b1a5147606e 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c @@ -1221,12 +1221,12 @@ int amdgpu_mes_ctx_map_meta_data(struct amdgpu_device *adev, drm_exec_until_all_locked(&exec) { r = drm_exec_lock_obj(&exec, &ctx_data-meta_data_obj- tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error_fini_exec; r = amdgpu_vm_lock_pd(vm, &exec, 0); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error_fini_exec; } @@ -1292,12 +1292,12 @@ int amdgpu_mes_ctx_unmap_meta_data(struct amdgpu_device *adev, drm_exec_until_all_locked(&exec) { r = drm_exec_lock_obj(&exec, &ctx_data-meta_data_obj- tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto out_unlock; r = amdgpu_vm_lock_pd(vm, &exec, 0); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto out_unlock; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c index e22cb2b5cd92..72b8213e352c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c @@ -77,7 +77,7 @@ int amdgpu_seq64_map(struct amdgpu_device *adev, struct amdgpu_vm *vm, r = amdgpu_vm_lock_pd(vm, &exec, 0); if (likely(!r)) r = drm_exec_lock_obj(&exec, &bo-tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error; } @@ -138,7 +138,7 @@ void amdgpu_seq64_unmap(struct amdgpu_device *adev, struct amdgpu_fpriv *fpriv) r = amdgpu_vm_lock_pd(vm, &exec, 0); if (likely(!r)) r = drm_exec_lock_obj(&exec, &bo-tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c index e01c1c8e64c4..63392ce43945 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c @@ -89,12 +89,12 @@ static int map_ring_data(struct amdgpu_device *adev, struct amdgpu_vm *vm, drm_exec_init(&exec, 0, 0); drm_exec_until_all_locked(&exec) { r = drm_exec_lock_obj(&exec, &bo-tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error_fini_exec; r = amdgpu_vm_lock_pd(vm, &exec, 0); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto error_fini_exec; } @@ -152,12 +152,12 @@ static int unmap_ring_data(struct amdgpu_device *adev, struct amdgpu_vm *vm, drm_exec_init(&exec, 0, 0); drm_exec_until_all_locked(&exec) { r = drm_exec_lock_obj(&exec, &bo-tbo.base);- drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto out_unlock; r = amdgpu_vm_lock_pd(vm, &exec, 0); - drm_exec_retry_on_contention(&exec); + r = drm_exec_retry_on_contention(&exec, r); if (unlikely(r)) goto out_unlock; } diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 386875e6eb96..a3aa7fd22f6a 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -1499,7 +1499,7 @@ static int svm_range_reserve_bos(struct svm_validate_context *ctx, bool intr) vm = drm_priv_to_vm(pdd-drm_priv);r = amdgpu_vm_lock_pd(vm, &ctx-exec,2); - drm_exec_retry_on_contention(&ctx-exec);+ r = drm_exec_retry_on_contention(&ctx-exec, r);if (unlikely(r)) { pr_debug("failed %d to reserve bo\n", r); goto unreserve_out; diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c index 2da094bdf8a4..3770a5d30213 100644 --- a/drivers/gpu/drm/drm_exec.c +++ b/drivers/gpu/drm/drm_exec.c @@ -28,12 +28,12 @@ * drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT); * drm_exec_until_all_locked(&exec) { * ret = drm_exec_prepare_obj(&exec, boA, 1); - * drm_exec_retry_on_contention(&exec); + * ret = drm_exec_retry_on_contention(&exec, ret); * if (ret) * goto error; * * ret = drm_exec_prepare_obj(&exec, boB, 1); - * drm_exec_retry_on_contention(&exec); + * ret = drm_exec_retry_on_contention(&exec, ret); * if (ret) * goto error; * } @@ -48,7 +48,8 @@ */ /* Dummy value used to initially enter the retry loop */ -#define DRM_EXEC_DUMMY ((void *)~0) +#define DRM_EXEC_DUMMY ERR_PTR(-ESTALE) +#define DRM_EXEC_CONTENDED ERR_PTR(-EDEADLK) /* Unlock all objects and drop references */ static void drm_exec_unlock_all(struct drm_exec *exec) @@ -131,8 +132,7 @@ bool drm_exec_cleanup(struct drm_exec *exec) return true; } - drm_exec_unlock_all(exec); - exec->num_objects = 0; + exec->contended = NULL; return true; } EXPORT_SYMBOL(drm_exec_cleanup); @@ -194,6 +194,27 @@ static int drm_exec_lock_contended(struct drm_exec *exec) return ret; } +/** + * drm_exec_handle_contended() - Perform cleanup before a ww transaction restart + * @exec: Pointer to the drm_exec object. + * + * Unlocks all held resvs and re-locks the contended object. + * + * Return: 0 on success, negative error code on failure. + */ +int drm_exec_handle_contended(struct drm_exec *exec) +{ + int ret; + + drm_exec_unlock_all(exec); + exec->num_objects = 0; + ret = drm_exec_lock_contended(exec); + exec->contended = DRM_EXEC_CONTENDED; + + return ret; +} +EXPORT_SYMBOL(drm_exec_handle_contended); + /** * drm_exec_lock_obj - lock a GEM object for use * @exec: the drm_exec object with the state @@ -209,10 +230,6 @@ int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj) { int ret; - ret = drm_exec_lock_contended(exec); - if (unlikely(ret)) - return ret; - if (exec->prelocked == obj) { drm_gem_object_put(exec->prelocked); exec->prelocked = NULL; diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c index f9eb56f24bef..0923d6ae18e2 100644 --- a/drivers/gpu/drm/drm_gpuvm.c +++ b/drivers/gpu/drm/drm_gpuvm.c @@ -1254,18 +1254,18 @@ drm_gpuvm_exec_lock(struct drm_gpuvm_exec *vm_exec) drm_exec_until_all_locked(exec) { ret = drm_gpuvm_prepare_vm(gpuvm, exec, num_fences); - drm_exec_retry_on_contention(exec); + ret = drm_exec_retry_on_contention(exec, ret); if (ret) goto err; ret = drm_gpuvm_prepare_objects(gpuvm, exec, num_fences); - drm_exec_retry_on_contention(exec); + ret = drm_exec_retry_on_contention(exec, ret); if (ret) goto err; if (vm_exec->extra.fn) { ret = vm_exec-extra.fn(vm_exec);- drm_exec_retry_on_contention(exec); + ret = drm_exec_retry_on_contention(exec, ret); if (ret) goto err; } @@ -1346,7 +1346,7 @@ drm_gpuvm_exec_lock_range(struct drm_gpuvm_exec *vm_exec, drm_exec_until_all_locked(exec) { ret = drm_gpuvm_prepare_range(gpuvm, exec, addr, range, vm_exec-num_fences);- drm_exec_retry_on_contention(exec); + ret = drm_exec_retry_on_contention(exec, ret); if (ret) goto err; } diff --git a/drivers/gpu/drm/imagination/pvr_job.c b/drivers/gpu/drm/imagination/pvr_job.c index 78c2f3c6dce0..6e0ce6c4576c 100644 --- a/drivers/gpu/drm/imagination/pvr_job.c +++ b/drivers/gpu/drm/imagination/pvr_job.c @@ -574,7 +574,7 @@ prepare_job_resvs_for_each(struct drm_exec *exec, struct pvr_job_data *job_data, drm_exec_until_all_locked(exec) { int err = jobs_lock_all_objs(exec, job_data, job_count); - drm_exec_retry_on_contention(exec); + err = drm_exec_retry_on_contention(exec, err); if (err) return err; } diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c index fba78193127d..01992b43ea4b 100644 --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -259,7 +259,7 @@ static int submit_lock_objects(struct msm_gem_submit *submit) for (unsigned i = 0; i < submit->nr_bos; i++) { struct drm_gem_object *obj = submit-bos[i].obj;ret = drm_exec_prepare_obj(&submit-exec,obj, 1); - drm_exec_retry_on_contention(&su bmit-exec);+ ret = drm_exec_retry_on_contention(&submit->exec, ret); if (ret) goto error; } diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm/nouveau/nouveau_uvmm.c index ee02cd833c5e..0c871634fdfb 100644 --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c @@ -1350,7 +1350,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job *job, drm_exec_init(exec, vme->flags, 0); drm_exec_until_all_locked(exec) { ret = bind_lock_validate(job, exec, vme-num_fences);- drm_exec_retry_on_contention(exec); + ret = drm_exec_retry_on_contention(exec, ret); if (ret) { op = list_last_op(&bind_job-ops);goto unwind; diff --git a/drivers/gpu/drm/tests/drm_exec_test.c b/drivers/gpu/drm/tests/drm_exec_test.c index 81f928a429ba..28558fdb08df 100644 --- a/drivers/gpu/drm/tests/drm_exec_test.c +++ b/drivers/gpu/drm/tests/drm_exec_test.c @@ -63,7 +63,7 @@ static void test_lock(struct kunit *test) drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); drm_exec_until_all_locked(&exec) { ret = drm_exec_lock_obj(&exec, &gobj); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); KUNIT_EXPECT_EQ(test, ret, 0); if (ret) break; @@ -83,14 +83,14 @@ static void test_lock_unlock(struct kunit *test) drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); drm_exec_until_all_locked(&exec) { ret = drm_exec_lock_obj(&exec, &gobj); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); KUNIT_EXPECT_EQ(test, ret, 0); if (ret) break; drm_exec_unlock_obj(&exec, &gobj); ret = drm_exec_lock_obj(&exec, &gobj); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); KUNIT_EXPECT_EQ(test, ret, 0); if (ret) break; @@ -110,13 +110,13 @@ static void test_duplicates(struct kunit *test) drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0); drm_exec_until_all_locked(&exec) { ret = drm_exec_lock_obj(&exec, &gobj); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); KUNIT_EXPECT_EQ(test, ret, 0); if (ret) break; ret = drm_exec_lock_obj(&exec, &gobj); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); KUNIT_EXPECT_EQ(test, ret, 0); if (ret) break; @@ -137,7 +137,7 @@ static void test_prepare(struct kunit *test) drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); drm_exec_until_all_locked(&exec) { ret = drm_exec_prepare_obj(&exec, &gobj, 1); - drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); KUNIT_EXPECT_EQ(test, ret, 0); if (ret) break; diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c index 040dd142c49c..20ec1ab1b52d 100644 --- a/drivers/gpu/drm/xe/xe_gt_pagefault.c +++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c @@ -200,7 +200,7 @@ static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf) drm_exec_init(&exec, 0, 0); drm_exec_until_all_locked(&exec) { ret = xe_pf_begin(&exec, vma, atomic, tile-id);- drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); if (ret) goto unlock_dma_resv; @@ -543,7 +543,7 @@ static int handle_acc(struct xe_gt *gt, struct acc *acc) drm_exec_init(&exec, 0, 0); drm_exec_until_all_locked(&exec) { ret = xe_pf_begin(&exec, vma, true, tile-id);- drm_exec_retry_on_contention(&exec); + ret = drm_exec_retry_on_contention(&exec, ret); if (ret) break; } diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index e2ec148c9c33..335524e803e7 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -501,7 +501,7 @@ static void preempt_rebind_work_func(struct work_struct *w) bool done = false; err = xe_preempt_work_begin(&exec, vm, &done); - drm_exec_retry_on_contention(&exec); + err = drm_exec_retry_on_contention(&exec, err); if (err || done) { drm_exec_fini(&exec); if (err && xe_vm_validate_should_retry(&exec, err, &end)) @@ -1052,7 +1052,7 @@ static void xe_vma_destroy_unlocked(struct xe_vma *vma) drm_exec_init(&exec, 0, 0); drm_exec_until_all_locked(&exec) { err = xe_vm_lock_vma(&exec, vma); - drm_exec_retry_on_contention(&exec); + err = drm_exec_retry_on_contention(&exec, err); if (XE_WARN_ON(err)) break; } @@ -2148,11 +2148,11 @@ static struct xe_vma *new_vma(struct xe_vm *vm, struct drm_gpuva_op_map *op, err = 0; if (!bo->vm) { err = drm_exec_lock_obj(&exec, xe_vm_obj(vm)); - drm_exec_retry_on_conten tion (& exec); + err = drm_exec_retry_on_contention(&exec, err); } if (!err) { err = drm_exec_lock_obj(&exec, &bo->ttm.base); - drm_exec_retry_on_conten tion (& exec); + err = drm_exec_retry_on_contention(&exec, err); } if (err) { drm_exec_fini(&exec); @@ -2884,7 +2884,7 @@ static int vm_bind_ioctl_ops_execute(struct xe_vm *vm, DRM_EXEC_IGNORE_DUPLICATES, 0); drm_exec_until_all_locked(&exec) { err = vm_bind_ioctl_ops_lock_and_prep(&exec, vm, vops); - drm_exec_retry_on_contention(&exec); + err = drm_exec_retry_on_contention(&exec, err); if (err) goto unlock; diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h index aa786b828a0a..fafb40d96e38 100644 --- a/include/drm/drm_exec.h +++ b/include/drm/drm_exec.h @@ -51,6 +51,8 @@ struct drm_exec { struct drm_gem_object *prelocked; }; +int drm_exec_handle_contended(struct drm_exec *exec); + /** * drm_exec_obj() - Return the object for a give drm_exec index * @exec: Pointer to the drm_exec context @@ -113,15 +115,26 @@ __PASTE(__drm_exec_, __LINE__): \ /** * drm_exec_retry_on_contention - restart the loop to grap all locks * @exec: drm_exec object + * @_ret: The current error status * * Control flow helper to continue when a contention was detected and we need to * clean up and re-start the loop to prepare all GEM objects. + * + * Return: If no loop restart occurred: The error status. */ -#define drm_exec_retry_on_contention(exec) \ - do { \ - if (unlikely(drm_exec_is_contended(exec))) \ - goto *__drm_exec_retry_ptr; \ - } while (0) +#define drm_exec_retry_on_contention(exec, _ret) \ + ({ \ + struct drm_exec *__exec = (exec); \ + int __ret = (_ret); \ + \ + if (unlikely(drm_exec_is_contended(__exec))) { \ + WARN_ON(__ret != - EDEADLK); \ + __ret = drm_exec_handle_contended(__exec); \ + if (!__ret) \ + goto *__drm_exec_retry_ptr; \ + } \ + __ret; \ + }) /** * drm_exec_is_contended - check for contention
