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bh=oJpSbgH1kSgDU7Y0Hz6JGSQ7iOD1Ubft/YjW5Br290M=; b=eZ06dPYx9Q0BMTa07WfDLElAayQqqXIXyLmvy7xEnsuaMF6lmkaw7bDFp9ly2p9V6i 392fLShJBv1BHl2YHIHR4Yw+AksH9IZF/aSMWRORiLYrAWBh7qT7MEJewfLwtQC1MOTW CKS1eGPlBBKiKpgoOR7BmOTLquF38vbOlW+cV3LvzpaThZ9bVpbeItQLJrpX+vg8+BbY OfnOi0R0t5TiUF5v5XdSmdxGuBbOTdji/WLVUqd2ctY0eVLq6YvxQbR5KK6Ock9IWFI+ Ly9GlxZ96YuNCBC4D5TtQuFpOVE1/ef+/barYIq1gbx63Io5GPlWB5bQDTefwkfVM5gR KOFA== X-Gm-Message-State: AOAM531RZ6b+V683bGos4weJOpm0DFNMLR1p++7SmESfaFiq2knAv+Og NO3DU9evDpO3909gKNDaMd2eXg== X-Google-Smtp-Source: ABdhPJw9UtwjQJxnEy8IJZh5KJnbYGRJV0mwbd+Yy5+O32Tmg0b1PQe33g4RiZ28BWXJHl47JY6dwA== X-Received: by 2002:a5d:4086:: with SMTP id o6mr6788445wrp.379.1625738553754; Thu, 08 Jul 2021 03:02:33 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id z4sm1501065wmf.9.2021.07.08.03.02.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jul 2021 03:02:32 -0700 (PDT) Date: Thu, 8 Jul 2021 12:02:29 +0200 From: Daniel Vetter To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Daniel Vetter , DRI Development , Steven Price , Daniel Vetter , Lucas Stach , Russell King , Christian Gmeiner , Qiang Yu , Rob Herring , Tomeu Vizoso , Alyssa Rosenzweig , David Airlie , Sumit Semwal , Masahiro Yamada , Kees Cook , Adam Borowski , Nick Terrell , Mauro Carvalho Chehab , Paul Menzel , Sami Tolvanen , Viresh Kumar , Alex Deucher , Dave Airlie , Nirmoy Das , Deepak R Varma , Lee Jones , Kevin Wang , Chen Li , Luben Tuikov , Marek =?utf-8?B?T2zFocOhaw==?= , Dennis Li , Maarten Lankhorst , Andrey Grodzovsky , Sonny Jiang , Boris Brezillon , Tian Tao , Jack Zhang , The etnaviv authors , lima@lists.freedesktop.org, "open list:DMA BUFFER SHARING FRAMEWORK" , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Emma Anholt Subject: Re: [PATCH v2 01/11] drm/sched: Split drm_sched_job_init Message-ID: References: <8387b5f8-a5f6-fc2d-48e6-4bb0768ac642@amd.com> <7933a995-0c95-9339-5385-a24681f6df3a@amd.com> <4369ee92-7eba-3faa-4d9c-08901d3506aa@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4369ee92-7eba-3faa-4d9c-08901d3506aa@amd.com> X-Operating-System: Linux phenom 5.10.0-7-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Thu, Jul 08, 2021 at 09:53:00AM +0200, Christian König wrote: > Am 08.07.21 um 09:19 schrieb Daniel Vetter: > > On Thu, Jul 8, 2021 at 9:09 AM Daniel Vetter wrote: > > > On Thu, Jul 8, 2021 at 8:56 AM Christian König wrote: > > > > Am 07.07.21 um 18:32 schrieb Daniel Vetter: > > > > > On Wed, Jul 7, 2021 at 2:58 PM Christian König wrote: > > > > > > Am 07.07.21 um 14:13 schrieb Daniel Vetter: > > > > > > > On Wed, Jul 7, 2021 at 1:57 PM Christian König wrote: > > > > > > > > Am 07.07.21 um 13:14 schrieb Daniel Vetter: > > > > > > > > > On Wed, Jul 7, 2021 at 11:30 AM Christian König > > > > > > > > > wrote: > > > > > > > > > > Am 02.07.21 um 23:38 schrieb Daniel Vetter: > > > > > > > > > > > This is a very confusingly named function, because not just does it > > > > > > > > > > > init an object, it arms it and provides a point of no return for > > > > > > > > > > > pushing a job into the scheduler. It would be nice if that's a bit > > > > > > > > > > > clearer in the interface. > > > > > > > > > > > > > > > > > > > > > > But the real reason is that I want to push the dependency tracking > > > > > > > > > > > helpers into the scheduler code, and that means drm_sched_job_init > > > > > > > > > > > must be called a lot earlier, without arming the job. > > > > > > > > > > > > > > > > > > > > > > v2: > > > > > > > > > > > - don't change .gitignore (Steven) > > > > > > > > > > > - don't forget v3d (Emma) > > > > > > > > > > > > > > > > > > > > > > v3: Emma noticed that I leak the memory allocated in > > > > > > > > > > > drm_sched_job_init if we bail out before the point of no return in > > > > > > > > > > > subsequent driver patches. To be able to fix this change > > > > > > > > > > > drm_sched_job_cleanup() so it can handle being called both before and > > > > > > > > > > > after drm_sched_job_arm(). > > > > > > > > > > Thinking more about this, I'm not sure if this really works. > > > > > > > > > > > > > > > > > > > > See drm_sched_job_init() was also calling drm_sched_entity_select_rq() > > > > > > > > > > to update the entity->rq association. > > > > > > > > > > > > > > > > > > > > And that can only be done later on when we arm the fence as well. > > > > > > > > > Hm yeah, but that's a bug in the existing code I think: We already > > > > > > > > > fail to clean up if we fail to allocate the fences. So I think the > > > > > > > > > right thing to do here is to split the checks into job_init, and do > > > > > > > > > the actual arming/rq selection in job_arm? I'm not entirely sure > > > > > > > > > what's all going on there, the first check looks a bit like trying to > > > > > > > > > schedule before the entity is set up, which is a driver bug and should > > > > > > > > > have a WARN_ON? > > > > > > > > No you misunderstood me, the problem is something else. > > > > > > > > > > > > > > > > You asked previously why the call to drm_sched_job_init() was so late in > > > > > > > > the CS. > > > > > > > > > > > > > > > > The reason for this was not alone the scheduler fence init, but also the > > > > > > > > call to drm_sched_entity_select_rq(). > > > > > > > Ah ok, I think I can fix that. Needs a prep patch to first make > > > > > > > drm_sched_entity_select infallible, then should be easy to do. > > > > > > > > > > > > > > > > The 2nd check around last_scheduled I have honeslty no idea what it's > > > > > > > > > even trying to do. > > > > > > > > You mean that here? > > > > > > > > > > > > > > > > fence = READ_ONCE(entity->last_scheduled); > > > > > > > > if (fence && !dma_fence_is_signaled(fence)) > > > > > > > > return; > > > > > > > > > > > > > > > > This makes sure that load balancing is not moving the entity to a > > > > > > > > different scheduler while there are still jobs running from this entity > > > > > > > > on the hardware, > > > > > > > Yeah after a nap that idea crossed my mind too. But now I have locking > > > > > > > questions, afaiui the scheduler thread updates this, without taking > > > > > > > any locks - entity dequeuing is lockless. And here we read the fence > > > > > > > and then seem to yolo check whether it's signalled? What's preventing > > > > > > > a use-after-free here? There's no rcu or anything going on here at > > > > > > > all, and it's outside of the spinlock section, which starts a bit > > > > > > > further down. > > > > > > The last_scheduled fence of an entity can only change when there are > > > > > > jobs on the entities queued, and we have just ruled that out in the > > > > > > check before. > > > > > There aren't any barriers, so the cpu could easily run the two checks > > > > > the other way round. I'll ponder this and figure out where exactly we > > > > > need docs for the constraint and/or barriers to make this work as > > > > > intended. As-is I'm not seeing how it does ... > > > > spsc_queue_count() provides the necessary barrier with the atomic_read(). > > > atomic_t is fully unordered, except when it's a read-modify-write > > Wasn't awake yet, I think the rule is read-modify-write and return > > previous value gives you full barrier. So stuff like cmpxchg, but also > > a few others. See atomic_t.txt under ODERING heading (yes that > > maintainer refuses to accept .rst so I can't just link you to the > > right section, it's silly). get/set and even RMW atomic ops that don't > > return anything are all fully unordered. > > As far as I know that not completely correct. The rules around atomics i > once learned are: > > 1. Everything which modifies something is a write barrier. > 2. Everything which returns something is a read barrier. > > And I know a whole bunch of use cases where this is relied upon in the core > kernel, so I'm pretty sure that's correct. That's against what the doc says, and also it would mean stuff like atomic_read_acquire or smp_mb__after/before_atomic is completely pointless. On x86 you're right, anywhere else where there's no total store ordering I you're wrong. If there's code that relies on this it needs to be fixed and properly documented. I did go through the squeue code a bit, and might be better to just replace this with a core data structure. -Daniel > In this case the write barrier is the atomic_dec() in spsc_queue_pop() and > the read barrier is the aromic_read() in spsc_queue_count(). > > The READ_ONCE() is actually not even necessary as far as I can see. > > Christian. > > > -Daniel > > > > > > > atomic op, then it's a full barrier. So yeah you need more here. But > > > also since you only need a read barrier on one side, and a write > > > barrier on the other, you don't actually need a cpu barriers on x86. > > > And READ_ONCE gives you the compiler barrier on one side at least, I > > > haven't found it on the writer side yet. > > > > > > > But yes a comment would be really nice here. I had to think for a while > > > > why we don't need this as well. > > > I'm typing a patch, which after a night's sleep I realized has the > > > wrong barriers. And now I'm also typing some doc improvements for > > > drm_sched_entity and related functions. > > > > > > > Christian. > > > > > > > > > -Daniel > > > > > > > > > > > Christian. > > > > > > > > > > > > > > > > > > > -Daniel > > > > > > > > > > > > > > > Regards > > > > > > > > Christian. > > > > > > > > > > > > > > > > > -Daniel > > > > > > > > > > > > > > > > > > > Christian. > > > > > > > > > > > > > > > > > > > > > Also improve the kerneldoc for this. > > > > > > > > > > > > > > > > > > > > > > Acked-by: Steven Price (v2) > > > > > > > > > > > Signed-off-by: Daniel Vetter > > > > > > > > > > > Cc: Lucas Stach > > > > > > > > > > > Cc: Russell King > > > > > > > > > > > Cc: Christian Gmeiner > > > > > > > > > > > Cc: Qiang Yu > > > > > > > > > > > Cc: Rob Herring > > > > > > > > > > > Cc: Tomeu Vizoso > > > > > > > > > > > Cc: Steven Price > > > > > > > > > > > Cc: Alyssa Rosenzweig > > > > > > > > > > > Cc: David Airlie > > > > > > > > > > > Cc: Daniel Vetter > > > > > > > > > > > Cc: Sumit Semwal > > > > > > > > > > > Cc: "Christian König" > > > > > > > > > > > Cc: Masahiro Yamada > > > > > > > > > > > Cc: Kees Cook > > > > > > > > > > > Cc: Adam Borowski > > > > > > > > > > > Cc: Nick Terrell > > > > > > > > > > > Cc: Mauro Carvalho Chehab > > > > > > > > > > > Cc: Paul Menzel > > > > > > > > > > > Cc: Sami Tolvanen > > > > > > > > > > > Cc: Viresh Kumar > > > > > > > > > > > Cc: Alex Deucher > > > > > > > > > > > Cc: Dave Airlie > > > > > > > > > > > Cc: Nirmoy Das > > > > > > > > > > > Cc: Deepak R Varma > > > > > > > > > > > Cc: Lee Jones > > > > > > > > > > > Cc: Kevin Wang > > > > > > > > > > > Cc: Chen Li > > > > > > > > > > > Cc: Luben Tuikov > > > > > > > > > > > Cc: "Marek Olšák" > > > > > > > > > > > Cc: Dennis Li > > > > > > > > > > > Cc: Maarten Lankhorst > > > > > > > > > > > Cc: Andrey Grodzovsky > > > > > > > > > > > Cc: Sonny Jiang > > > > > > > > > > > Cc: Boris Brezillon > > > > > > > > > > > Cc: Tian Tao > > > > > > > > > > > Cc: Jack Zhang > > > > > > > > > > > Cc: etnaviv@lists.freedesktop.org > > > > > > > > > > > Cc: lima@lists.freedesktop.org > > > > > > > > > > > Cc: linux-media@vger.kernel.org > > > > > > > > > > > Cc: linaro-mm-sig@lists.linaro.org > > > > > > > > > > > Cc: Emma Anholt > > > > > > > > > > > --- > > > > > > > > > > > drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/etnaviv/etnaviv_sched.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/lima/lima_sched.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/panfrost/panfrost_job.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/scheduler/sched_entity.c | 6 ++-- > > > > > > > > > > > drivers/gpu/drm/scheduler/sched_fence.c | 17 +++++---- > > > > > > > > > > > drivers/gpu/drm/scheduler/sched_main.c | 46 +++++++++++++++++++++--- > > > > > > > > > > > drivers/gpu/drm/v3d/v3d_gem.c | 2 ++ > > > > > > > > > > > include/drm/gpu_scheduler.h | 7 +++- > > > > > > > > > > > 10 files changed, 74 insertions(+), 14 deletions(-) > > > > > > > > > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c > > > > > > > > > > > index c5386d13eb4a..a4ec092af9a7 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c > > > > > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c > > > > > > > > > > > @@ -1226,6 +1226,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p, > > > > > > > > > > > if (r) > > > > > > > > > > > goto error_unlock; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > /* No memory allocation is allowed while holding the notifier lock. > > > > > > > > > > > * The lock is held until amdgpu_cs_submit is finished and fence is > > > > > > > > > > > * added to BOs. > > > > > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c > > > > > > > > > > > index d33e6d97cc89..5ddb955d2315 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c > > > > > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c > > > > > > > > > > > @@ -170,6 +170,8 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity, > > > > > > > > > > > if (r) > > > > > > > > > > > return r; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > *f = dma_fence_get(&job->base.s_fence->finished); > > > > > > > > > > > amdgpu_job_free_resources(job); > > > > > > > > > > > drm_sched_entity_push_job(&job->base, entity); > > > > > > > > > > > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c > > > > > > > > > > > index feb6da1b6ceb..05f412204118 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c > > > > > > > > > > > +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c > > > > > > > > > > > @@ -163,6 +163,8 @@ int etnaviv_sched_push_job(struct drm_sched_entity *sched_entity, > > > > > > > > > > > if (ret) > > > > > > > > > > > goto out_unlock; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&submit->sched_job); > > > > > > > > > > > + > > > > > > > > > > > submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished); > > > > > > > > > > > submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr, > > > > > > > > > > > submit->out_fence, 0, > > > > > > > > > > > diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c > > > > > > > > > > > index dba8329937a3..38f755580507 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/lima/lima_sched.c > > > > > > > > > > > +++ b/drivers/gpu/drm/lima/lima_sched.c > > > > > > > > > > > @@ -129,6 +129,8 @@ int lima_sched_task_init(struct lima_sched_task *task, > > > > > > > > > > > return err; > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&task->base); > > > > > > > > > > > + > > > > > > > > > > > task->num_bos = num_bos; > > > > > > > > > > > task->vm = lima_vm_get(vm); > > > > > > > > > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c > > > > > > > > > > > index 71a72fb50e6b..2992dc85325f 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/panfrost/panfrost_job.c > > > > > > > > > > > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c > > > > > > > > > > > @@ -288,6 +288,8 @@ int panfrost_job_push(struct panfrost_job *job) > > > > > > > > > > > goto unlock; > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > job->render_done_fence = dma_fence_get(&job->base.s_fence->finished); > > > > > > > > > > > > > > > > > > > > > > ret = panfrost_acquire_object_fences(job->bos, job->bo_count, > > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c > > > > > > > > > > > index 79554aa4dbb1..f7347c284886 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/scheduler/sched_entity.c > > > > > > > > > > > +++ b/drivers/gpu/drm/scheduler/sched_entity.c > > > > > > > > > > > @@ -485,9 +485,9 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity) > > > > > > > > > > > * @sched_job: job to submit > > > > > > > > > > > * @entity: scheduler entity > > > > > > > > > > > * > > > > > > > > > > > - * Note: To guarantee that the order of insertion to queue matches > > > > > > > > > > > - * the job's fence sequence number this function should be > > > > > > > > > > > - * called with drm_sched_job_init under common lock. > > > > > > > > > > > + * Note: To guarantee that the order of insertion to queue matches the job's > > > > > > > > > > > + * fence sequence number this function should be called with drm_sched_job_arm() > > > > > > > > > > > + * under common lock. > > > > > > > > > > > * > > > > > > > > > > > * Returns 0 for success, negative error code otherwise. > > > > > > > > > > > */ > > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c > > > > > > > > > > > index 69de2c76731f..c451ee9a30d7 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/scheduler/sched_fence.c > > > > > > > > > > > +++ b/drivers/gpu/drm/scheduler/sched_fence.c > > > > > > > > > > > @@ -90,7 +90,7 @@ static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f) > > > > > > > > > > > * > > > > > > > > > > > * Free up the fence memory after the RCU grace period. > > > > > > > > > > > */ > > > > > > > > > > > -static void drm_sched_fence_free(struct rcu_head *rcu) > > > > > > > > > > > +void drm_sched_fence_free(struct rcu_head *rcu) > > > > > > > > > > > { > > > > > > > > > > > struct dma_fence *f = container_of(rcu, struct dma_fence, rcu); > > > > > > > > > > > struct drm_sched_fence *fence = to_drm_sched_fence(f); > > > > > > > > > > > @@ -152,11 +152,10 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f) > > > > > > > > > > > } > > > > > > > > > > > EXPORT_SYMBOL(to_drm_sched_fence); > > > > > > > > > > > > > > > > > > > > > > -struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity, > > > > > > > > > > > - void *owner) > > > > > > > > > > > +struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity, > > > > > > > > > > > + void *owner) > > > > > > > > > > > { > > > > > > > > > > > struct drm_sched_fence *fence = NULL; > > > > > > > > > > > - unsigned seq; > > > > > > > > > > > > > > > > > > > > > > fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL); > > > > > > > > > > > if (fence == NULL) > > > > > > > > > > > @@ -166,13 +165,19 @@ struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity, > > > > > > > > > > > fence->sched = entity->rq->sched; > > > > > > > > > > > spin_lock_init(&fence->lock); > > > > > > > > > > > > > > > > > > > > > > + return fence; > > > > > > > > > > > +} > > > > > > > > > > > + > > > > > > > > > > > +void drm_sched_fence_init(struct drm_sched_fence *fence, > > > > > > > > > > > + struct drm_sched_entity *entity) > > > > > > > > > > > +{ > > > > > > > > > > > + unsigned seq; > > > > > > > > > > > + > > > > > > > > > > > seq = atomic_inc_return(&entity->fence_seq); > > > > > > > > > > > dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled, > > > > > > > > > > > &fence->lock, entity->fence_context, seq); > > > > > > > > > > > dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished, > > > > > > > > > > > &fence->lock, entity->fence_context + 1, seq); > > > > > > > > > > > - > > > > > > > > > > > - return fence; > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > module_init(drm_sched_fence_slab_init); > > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c > > > > > > > > > > > index 33c414d55fab..5e84e1500c32 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/scheduler/sched_main.c > > > > > > > > > > > +++ b/drivers/gpu/drm/scheduler/sched_main.c > > > > > > > > > > > @@ -48,9 +48,11 @@ > > > > > > > > > > > #include > > > > > > > > > > > #include > > > > > > > > > > > #include > > > > > > > > > > > +#include > > > > > > > > > > > #include > > > > > > > > > > > > > > > > > > > > > > #include > > > > > > > > > > > +#include > > > > > > > > > > > #include > > > > > > > > > > > #include > > > > > > > > > > > > > > > > > > > > > > @@ -569,7 +571,6 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext); > > > > > > > > > > > > > > > > > > > > > > /** > > > > > > > > > > > * drm_sched_job_init - init a scheduler job > > > > > > > > > > > - * > > > > > > > > > > > * @job: scheduler job to init > > > > > > > > > > > * @entity: scheduler entity to use > > > > > > > > > > > * @owner: job owner for debugging > > > > > > > > > > > @@ -577,6 +578,9 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext); > > > > > > > > > > > * Refer to drm_sched_entity_push_job() documentation > > > > > > > > > > > * for locking considerations. > > > > > > > > > > > * > > > > > > > > > > > + * Drivers must make sure drm_sched_job_cleanup() if this function returns > > > > > > > > > > > + * successfully, even when @job is aborted before drm_sched_job_arm() is called. > > > > > > > > > > > + * > > > > > > > > > > > * Returns 0 for success, negative error code otherwise. > > > > > > > > > > > */ > > > > > > > > > > > int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > @@ -594,7 +598,7 @@ int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > job->sched = sched; > > > > > > > > > > > job->entity = entity; > > > > > > > > > > > job->s_priority = entity->rq - sched->sched_rq; > > > > > > > > > > > - job->s_fence = drm_sched_fence_create(entity, owner); > > > > > > > > > > > + job->s_fence = drm_sched_fence_alloc(entity, owner); > > > > > > > > > > > if (!job->s_fence) > > > > > > > > > > > return -ENOMEM; > > > > > > > > > > > job->id = atomic64_inc_return(&sched->job_id_count); > > > > > > > > > > > @@ -606,13 +610,47 @@ int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > EXPORT_SYMBOL(drm_sched_job_init); > > > > > > > > > > > > > > > > > > > > > > /** > > > > > > > > > > > - * drm_sched_job_cleanup - clean up scheduler job resources > > > > > > > > > > > + * drm_sched_job_arm - arm a scheduler job for execution > > > > > > > > > > > + * @job: scheduler job to arm > > > > > > > > > > > + * > > > > > > > > > > > + * This arms a scheduler job for execution. Specifically it initializes the > > > > > > > > > > > + * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv > > > > > > > > > > > + * or other places that need to track the completion of this job. > > > > > > > > > > > + * > > > > > > > > > > > + * Refer to drm_sched_entity_push_job() documentation for locking > > > > > > > > > > > + * considerations. > > > > > > > > > > > * > > > > > > > > > > > + * This can only be called if drm_sched_job_init() succeeded. > > > > > > > > > > > + */ > > > > > > > > > > > +void drm_sched_job_arm(struct drm_sched_job *job) > > > > > > > > > > > +{ > > > > > > > > > > > + drm_sched_fence_init(job->s_fence, job->entity); > > > > > > > > > > > +} > > > > > > > > > > > +EXPORT_SYMBOL(drm_sched_job_arm); > > > > > > > > > > > + > > > > > > > > > > > +/** > > > > > > > > > > > + * drm_sched_job_cleanup - clean up scheduler job resources > > > > > > > > > > > * @job: scheduler job to clean up > > > > > > > > > > > + * > > > > > > > > > > > + * Cleans up the resources allocated with drm_sched_job_init(). > > > > > > > > > > > + * > > > > > > > > > > > + * Drivers should call this from their error unwind code if @job is aborted > > > > > > > > > > > + * before drm_sched_job_arm() is called. > > > > > > > > > > > + * > > > > > > > > > > > + * After that point of no return @job is committed to be executed by the > > > > > > > > > > > + * scheduler, and this function should be called from the > > > > > > > > > > > + * &drm_sched_backend_ops.free_job callback. > > > > > > > > > > > */ > > > > > > > > > > > void drm_sched_job_cleanup(struct drm_sched_job *job) > > > > > > > > > > > { > > > > > > > > > > > - dma_fence_put(&job->s_fence->finished); > > > > > > > > > > > + if (!kref_read(&job->s_fence->finished.refcount)) { > > > > > > > > > > > + /* drm_sched_job_arm() has been called */ > > > > > > > > > > > + dma_fence_put(&job->s_fence->finished); > > > > > > > > > > > + } else { > > > > > > > > > > > + /* aborted job before committing to run it */ > > > > > > > > > > > + drm_sched_fence_free(&job->s_fence->finished.rcu); > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > job->s_fence = NULL; > > > > > > > > > > > } > > > > > > > > > > > EXPORT_SYMBOL(drm_sched_job_cleanup); > > > > > > > > > > > diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c > > > > > > > > > > > index 4eb354226972..5c3a99027ecd 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/v3d/v3d_gem.c > > > > > > > > > > > +++ b/drivers/gpu/drm/v3d/v3d_gem.c > > > > > > > > > > > @@ -475,6 +475,8 @@ v3d_push_job(struct v3d_file_priv *v3d_priv, > > > > > > > > > > > if (ret) > > > > > > > > > > > return ret; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > job->done_fence = dma_fence_get(&job->base.s_fence->finished); > > > > > > > > > > > > > > > > > > > > > > /* put by scheduler job completion */ > > > > > > > > > > > diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h > > > > > > > > > > > index 88ae7f331bb1..83afc3aa8e2f 100644 > > > > > > > > > > > --- a/include/drm/gpu_scheduler.h > > > > > > > > > > > +++ b/include/drm/gpu_scheduler.h > > > > > > > > > > > @@ -348,6 +348,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched); > > > > > > > > > > > int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > struct drm_sched_entity *entity, > > > > > > > > > > > void *owner); > > > > > > > > > > > +void drm_sched_job_arm(struct drm_sched_job *job); > > > > > > > > > > > void drm_sched_entity_modify_sched(struct drm_sched_entity *entity, > > > > > > > > > > > struct drm_gpu_scheduler **sched_list, > > > > > > > > > > > unsigned int num_sched_list); > > > > > > > > > > > @@ -387,8 +388,12 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity, > > > > > > > > > > > enum drm_sched_priority priority); > > > > > > > > > > > bool drm_sched_entity_is_ready(struct drm_sched_entity *entity); > > > > > > > > > > > > > > > > > > > > > > -struct drm_sched_fence *drm_sched_fence_create( > > > > > > > > > > > +struct drm_sched_fence *drm_sched_fence_alloc( > > > > > > > > > > > struct drm_sched_entity *s_entity, void *owner); > > > > > > > > > > > +void drm_sched_fence_init(struct drm_sched_fence *fence, > > > > > > > > > > > + struct drm_sched_entity *entity); > > > > > > > > > > > +void drm_sched_fence_free(struct rcu_head *rcu); > > > > > > > > > > > + > > > > > > > > > > > void drm_sched_fence_scheduled(struct drm_sched_fence *fence); > > > > > > > > > > > void drm_sched_fence_finished(struct drm_sched_fence *fence); > > > > > > > > > > > > > > > > > -- > > > Daniel Vetter > > > Software Engineer, Intel Corporation > > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fblog.ffwll.ch%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C1ac51fc78f9f4e2f08a808d941e0c013%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637613255881294371%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=PRGZl6tUAc7FrL39mu%2BBV2AfC02Mz9R2Neqs5TjdB6M%3D&reserved=0 > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fblog.ffwll.ch%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C1ac51fc78f9f4e2f08a808d941e0c013%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637613255881294371%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=PRGZl6tUAc7FrL39mu%2BBV2AfC02Mz9R2Neqs5TjdB6M%3D&reserved=0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B635CC07E99 for ; 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Thu, 08 Jul 2021 03:02:33 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id z4sm1501065wmf.9.2021.07.08.03.02.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jul 2021 03:02:32 -0700 (PDT) Date: Thu, 8 Jul 2021 12:02:29 +0200 From: Daniel Vetter To: Christian =?iso-8859-1?Q?K=F6nig?= Subject: Re: [PATCH v2 01/11] drm/sched: Split drm_sched_job_init Message-ID: References: <8387b5f8-a5f6-fc2d-48e6-4bb0768ac642@amd.com> <7933a995-0c95-9339-5385-a24681f6df3a@amd.com> <4369ee92-7eba-3faa-4d9c-08901d3506aa@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4369ee92-7eba-3faa-4d9c-08901d3506aa@amd.com> X-Operating-System: Linux phenom 5.10.0-7-amd64 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Emma Anholt , Adam Borowski , David Airlie , Daniel Vetter , DRI Development , Sonny Jiang , Nirmoy Das , Daniel Vetter , Lee Jones , Jack Zhang , lima@lists.freedesktop.org, Mauro Carvalho Chehab , Masahiro Yamada , Steven Price , Luben Tuikov , Alyssa Rosenzweig , Sami Tolvanen , Viresh Kumar , Dave Airlie , Dennis Li , Chen Li , Paul Menzel , Kevin Wang , Kees Cook , Marek =?utf-8?B?T2zFocOhaw==?= , Russell King , The etnaviv authors , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Nick Terrell , Deepak R Varma , Tomeu Vizoso , Boris Brezillon , Qiang Yu , Alex Deucher , Tian Tao , "open list:DMA BUFFER SHARING FRAMEWORK" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Jul 08, 2021 at 09:53:00AM +0200, Christian König wrote: > Am 08.07.21 um 09:19 schrieb Daniel Vetter: > > On Thu, Jul 8, 2021 at 9:09 AM Daniel Vetter wrote: > > > On Thu, Jul 8, 2021 at 8:56 AM Christian König wrote: > > > > Am 07.07.21 um 18:32 schrieb Daniel Vetter: > > > > > On Wed, Jul 7, 2021 at 2:58 PM Christian König wrote: > > > > > > Am 07.07.21 um 14:13 schrieb Daniel Vetter: > > > > > > > On Wed, Jul 7, 2021 at 1:57 PM Christian König wrote: > > > > > > > > Am 07.07.21 um 13:14 schrieb Daniel Vetter: > > > > > > > > > On Wed, Jul 7, 2021 at 11:30 AM Christian König > > > > > > > > > wrote: > > > > > > > > > > Am 02.07.21 um 23:38 schrieb Daniel Vetter: > > > > > > > > > > > This is a very confusingly named function, because not just does it > > > > > > > > > > > init an object, it arms it and provides a point of no return for > > > > > > > > > > > pushing a job into the scheduler. It would be nice if that's a bit > > > > > > > > > > > clearer in the interface. > > > > > > > > > > > > > > > > > > > > > > But the real reason is that I want to push the dependency tracking > > > > > > > > > > > helpers into the scheduler code, and that means drm_sched_job_init > > > > > > > > > > > must be called a lot earlier, without arming the job. > > > > > > > > > > > > > > > > > > > > > > v2: > > > > > > > > > > > - don't change .gitignore (Steven) > > > > > > > > > > > - don't forget v3d (Emma) > > > > > > > > > > > > > > > > > > > > > > v3: Emma noticed that I leak the memory allocated in > > > > > > > > > > > drm_sched_job_init if we bail out before the point of no return in > > > > > > > > > > > subsequent driver patches. To be able to fix this change > > > > > > > > > > > drm_sched_job_cleanup() so it can handle being called both before and > > > > > > > > > > > after drm_sched_job_arm(). > > > > > > > > > > Thinking more about this, I'm not sure if this really works. > > > > > > > > > > > > > > > > > > > > See drm_sched_job_init() was also calling drm_sched_entity_select_rq() > > > > > > > > > > to update the entity->rq association. > > > > > > > > > > > > > > > > > > > > And that can only be done later on when we arm the fence as well. > > > > > > > > > Hm yeah, but that's a bug in the existing code I think: We already > > > > > > > > > fail to clean up if we fail to allocate the fences. So I think the > > > > > > > > > right thing to do here is to split the checks into job_init, and do > > > > > > > > > the actual arming/rq selection in job_arm? I'm not entirely sure > > > > > > > > > what's all going on there, the first check looks a bit like trying to > > > > > > > > > schedule before the entity is set up, which is a driver bug and should > > > > > > > > > have a WARN_ON? > > > > > > > > No you misunderstood me, the problem is something else. > > > > > > > > > > > > > > > > You asked previously why the call to drm_sched_job_init() was so late in > > > > > > > > the CS. > > > > > > > > > > > > > > > > The reason for this was not alone the scheduler fence init, but also the > > > > > > > > call to drm_sched_entity_select_rq(). > > > > > > > Ah ok, I think I can fix that. Needs a prep patch to first make > > > > > > > drm_sched_entity_select infallible, then should be easy to do. > > > > > > > > > > > > > > > > The 2nd check around last_scheduled I have honeslty no idea what it's > > > > > > > > > even trying to do. > > > > > > > > You mean that here? > > > > > > > > > > > > > > > > fence = READ_ONCE(entity->last_scheduled); > > > > > > > > if (fence && !dma_fence_is_signaled(fence)) > > > > > > > > return; > > > > > > > > > > > > > > > > This makes sure that load balancing is not moving the entity to a > > > > > > > > different scheduler while there are still jobs running from this entity > > > > > > > > on the hardware, > > > > > > > Yeah after a nap that idea crossed my mind too. But now I have locking > > > > > > > questions, afaiui the scheduler thread updates this, without taking > > > > > > > any locks - entity dequeuing is lockless. And here we read the fence > > > > > > > and then seem to yolo check whether it's signalled? What's preventing > > > > > > > a use-after-free here? There's no rcu or anything going on here at > > > > > > > all, and it's outside of the spinlock section, which starts a bit > > > > > > > further down. > > > > > > The last_scheduled fence of an entity can only change when there are > > > > > > jobs on the entities queued, and we have just ruled that out in the > > > > > > check before. > > > > > There aren't any barriers, so the cpu could easily run the two checks > > > > > the other way round. I'll ponder this and figure out where exactly we > > > > > need docs for the constraint and/or barriers to make this work as > > > > > intended. As-is I'm not seeing how it does ... > > > > spsc_queue_count() provides the necessary barrier with the atomic_read(). > > > atomic_t is fully unordered, except when it's a read-modify-write > > Wasn't awake yet, I think the rule is read-modify-write and return > > previous value gives you full barrier. So stuff like cmpxchg, but also > > a few others. See atomic_t.txt under ODERING heading (yes that > > maintainer refuses to accept .rst so I can't just link you to the > > right section, it's silly). get/set and even RMW atomic ops that don't > > return anything are all fully unordered. > > As far as I know that not completely correct. The rules around atomics i > once learned are: > > 1. Everything which modifies something is a write barrier. > 2. Everything which returns something is a read barrier. > > And I know a whole bunch of use cases where this is relied upon in the core > kernel, so I'm pretty sure that's correct. That's against what the doc says, and also it would mean stuff like atomic_read_acquire or smp_mb__after/before_atomic is completely pointless. On x86 you're right, anywhere else where there's no total store ordering I you're wrong. If there's code that relies on this it needs to be fixed and properly documented. I did go through the squeue code a bit, and might be better to just replace this with a core data structure. -Daniel > In this case the write barrier is the atomic_dec() in spsc_queue_pop() and > the read barrier is the aromic_read() in spsc_queue_count(). > > The READ_ONCE() is actually not even necessary as far as I can see. > > Christian. > > > -Daniel > > > > > > > atomic op, then it's a full barrier. So yeah you need more here. But > > > also since you only need a read barrier on one side, and a write > > > barrier on the other, you don't actually need a cpu barriers on x86. > > > And READ_ONCE gives you the compiler barrier on one side at least, I > > > haven't found it on the writer side yet. > > > > > > > But yes a comment would be really nice here. I had to think for a while > > > > why we don't need this as well. > > > I'm typing a patch, which after a night's sleep I realized has the > > > wrong barriers. And now I'm also typing some doc improvements for > > > drm_sched_entity and related functions. > > > > > > > Christian. > > > > > > > > > -Daniel > > > > > > > > > > > Christian. > > > > > > > > > > > > > > > > > > > -Daniel > > > > > > > > > > > > > > > Regards > > > > > > > > Christian. > > > > > > > > > > > > > > > > > -Daniel > > > > > > > > > > > > > > > > > > > Christian. > > > > > > > > > > > > > > > > > > > > > Also improve the kerneldoc for this. > > > > > > > > > > > > > > > > > > > > > > Acked-by: Steven Price (v2) > > > > > > > > > > > Signed-off-by: Daniel Vetter > > > > > > > > > > > Cc: Lucas Stach > > > > > > > > > > > Cc: Russell King > > > > > > > > > > > Cc: Christian Gmeiner > > > > > > > > > > > Cc: Qiang Yu > > > > > > > > > > > Cc: Rob Herring > > > > > > > > > > > Cc: Tomeu Vizoso > > > > > > > > > > > Cc: Steven Price > > > > > > > > > > > Cc: Alyssa Rosenzweig > > > > > > > > > > > Cc: David Airlie > > > > > > > > > > > Cc: Daniel Vetter > > > > > > > > > > > Cc: Sumit Semwal > > > > > > > > > > > Cc: "Christian König" > > > > > > > > > > > Cc: Masahiro Yamada > > > > > > > > > > > Cc: Kees Cook > > > > > > > > > > > Cc: Adam Borowski > > > > > > > > > > > Cc: Nick Terrell > > > > > > > > > > > Cc: Mauro Carvalho Chehab > > > > > > > > > > > Cc: Paul Menzel > > > > > > > > > > > Cc: Sami Tolvanen > > > > > > > > > > > Cc: Viresh Kumar > > > > > > > > > > > Cc: Alex Deucher > > > > > > > > > > > Cc: Dave Airlie > > > > > > > > > > > Cc: Nirmoy Das > > > > > > > > > > > Cc: Deepak R Varma > > > > > > > > > > > Cc: Lee Jones > > > > > > > > > > > Cc: Kevin Wang > > > > > > > > > > > Cc: Chen Li > > > > > > > > > > > Cc: Luben Tuikov > > > > > > > > > > > Cc: "Marek Olšák" > > > > > > > > > > > Cc: Dennis Li > > > > > > > > > > > Cc: Maarten Lankhorst > > > > > > > > > > > Cc: Andrey Grodzovsky > > > > > > > > > > > Cc: Sonny Jiang > > > > > > > > > > > Cc: Boris Brezillon > > > > > > > > > > > Cc: Tian Tao > > > > > > > > > > > Cc: Jack Zhang > > > > > > > > > > > Cc: etnaviv@lists.freedesktop.org > > > > > > > > > > > Cc: lima@lists.freedesktop.org > > > > > > > > > > > Cc: linux-media@vger.kernel.org > > > > > > > > > > > Cc: linaro-mm-sig@lists.linaro.org > > > > > > > > > > > Cc: Emma Anholt > > > > > > > > > > > --- > > > > > > > > > > > drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/etnaviv/etnaviv_sched.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/lima/lima_sched.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/panfrost/panfrost_job.c | 2 ++ > > > > > > > > > > > drivers/gpu/drm/scheduler/sched_entity.c | 6 ++-- > > > > > > > > > > > drivers/gpu/drm/scheduler/sched_fence.c | 17 +++++---- > > > > > > > > > > > drivers/gpu/drm/scheduler/sched_main.c | 46 +++++++++++++++++++++--- > > > > > > > > > > > drivers/gpu/drm/v3d/v3d_gem.c | 2 ++ > > > > > > > > > > > include/drm/gpu_scheduler.h | 7 +++- > > > > > > > > > > > 10 files changed, 74 insertions(+), 14 deletions(-) > > > > > > > > > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c > > > > > > > > > > > index c5386d13eb4a..a4ec092af9a7 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c > > > > > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c > > > > > > > > > > > @@ -1226,6 +1226,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p, > > > > > > > > > > > if (r) > > > > > > > > > > > goto error_unlock; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > /* No memory allocation is allowed while holding the notifier lock. > > > > > > > > > > > * The lock is held until amdgpu_cs_submit is finished and fence is > > > > > > > > > > > * added to BOs. > > > > > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c > > > > > > > > > > > index d33e6d97cc89..5ddb955d2315 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c > > > > > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c > > > > > > > > > > > @@ -170,6 +170,8 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity, > > > > > > > > > > > if (r) > > > > > > > > > > > return r; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > *f = dma_fence_get(&job->base.s_fence->finished); > > > > > > > > > > > amdgpu_job_free_resources(job); > > > > > > > > > > > drm_sched_entity_push_job(&job->base, entity); > > > > > > > > > > > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c > > > > > > > > > > > index feb6da1b6ceb..05f412204118 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c > > > > > > > > > > > +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c > > > > > > > > > > > @@ -163,6 +163,8 @@ int etnaviv_sched_push_job(struct drm_sched_entity *sched_entity, > > > > > > > > > > > if (ret) > > > > > > > > > > > goto out_unlock; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&submit->sched_job); > > > > > > > > > > > + > > > > > > > > > > > submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished); > > > > > > > > > > > submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr, > > > > > > > > > > > submit->out_fence, 0, > > > > > > > > > > > diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c > > > > > > > > > > > index dba8329937a3..38f755580507 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/lima/lima_sched.c > > > > > > > > > > > +++ b/drivers/gpu/drm/lima/lima_sched.c > > > > > > > > > > > @@ -129,6 +129,8 @@ int lima_sched_task_init(struct lima_sched_task *task, > > > > > > > > > > > return err; > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&task->base); > > > > > > > > > > > + > > > > > > > > > > > task->num_bos = num_bos; > > > > > > > > > > > task->vm = lima_vm_get(vm); > > > > > > > > > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c > > > > > > > > > > > index 71a72fb50e6b..2992dc85325f 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/panfrost/panfrost_job.c > > > > > > > > > > > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c > > > > > > > > > > > @@ -288,6 +288,8 @@ int panfrost_job_push(struct panfrost_job *job) > > > > > > > > > > > goto unlock; > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > job->render_done_fence = dma_fence_get(&job->base.s_fence->finished); > > > > > > > > > > > > > > > > > > > > > > ret = panfrost_acquire_object_fences(job->bos, job->bo_count, > > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c > > > > > > > > > > > index 79554aa4dbb1..f7347c284886 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/scheduler/sched_entity.c > > > > > > > > > > > +++ b/drivers/gpu/drm/scheduler/sched_entity.c > > > > > > > > > > > @@ -485,9 +485,9 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity) > > > > > > > > > > > * @sched_job: job to submit > > > > > > > > > > > * @entity: scheduler entity > > > > > > > > > > > * > > > > > > > > > > > - * Note: To guarantee that the order of insertion to queue matches > > > > > > > > > > > - * the job's fence sequence number this function should be > > > > > > > > > > > - * called with drm_sched_job_init under common lock. > > > > > > > > > > > + * Note: To guarantee that the order of insertion to queue matches the job's > > > > > > > > > > > + * fence sequence number this function should be called with drm_sched_job_arm() > > > > > > > > > > > + * under common lock. > > > > > > > > > > > * > > > > > > > > > > > * Returns 0 for success, negative error code otherwise. > > > > > > > > > > > */ > > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c > > > > > > > > > > > index 69de2c76731f..c451ee9a30d7 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/scheduler/sched_fence.c > > > > > > > > > > > +++ b/drivers/gpu/drm/scheduler/sched_fence.c > > > > > > > > > > > @@ -90,7 +90,7 @@ static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f) > > > > > > > > > > > * > > > > > > > > > > > * Free up the fence memory after the RCU grace period. > > > > > > > > > > > */ > > > > > > > > > > > -static void drm_sched_fence_free(struct rcu_head *rcu) > > > > > > > > > > > +void drm_sched_fence_free(struct rcu_head *rcu) > > > > > > > > > > > { > > > > > > > > > > > struct dma_fence *f = container_of(rcu, struct dma_fence, rcu); > > > > > > > > > > > struct drm_sched_fence *fence = to_drm_sched_fence(f); > > > > > > > > > > > @@ -152,11 +152,10 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f) > > > > > > > > > > > } > > > > > > > > > > > EXPORT_SYMBOL(to_drm_sched_fence); > > > > > > > > > > > > > > > > > > > > > > -struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity, > > > > > > > > > > > - void *owner) > > > > > > > > > > > +struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity, > > > > > > > > > > > + void *owner) > > > > > > > > > > > { > > > > > > > > > > > struct drm_sched_fence *fence = NULL; > > > > > > > > > > > - unsigned seq; > > > > > > > > > > > > > > > > > > > > > > fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL); > > > > > > > > > > > if (fence == NULL) > > > > > > > > > > > @@ -166,13 +165,19 @@ struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity, > > > > > > > > > > > fence->sched = entity->rq->sched; > > > > > > > > > > > spin_lock_init(&fence->lock); > > > > > > > > > > > > > > > > > > > > > > + return fence; > > > > > > > > > > > +} > > > > > > > > > > > + > > > > > > > > > > > +void drm_sched_fence_init(struct drm_sched_fence *fence, > > > > > > > > > > > + struct drm_sched_entity *entity) > > > > > > > > > > > +{ > > > > > > > > > > > + unsigned seq; > > > > > > > > > > > + > > > > > > > > > > > seq = atomic_inc_return(&entity->fence_seq); > > > > > > > > > > > dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled, > > > > > > > > > > > &fence->lock, entity->fence_context, seq); > > > > > > > > > > > dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished, > > > > > > > > > > > &fence->lock, entity->fence_context + 1, seq); > > > > > > > > > > > - > > > > > > > > > > > - return fence; > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > module_init(drm_sched_fence_slab_init); > > > > > > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c > > > > > > > > > > > index 33c414d55fab..5e84e1500c32 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/scheduler/sched_main.c > > > > > > > > > > > +++ b/drivers/gpu/drm/scheduler/sched_main.c > > > > > > > > > > > @@ -48,9 +48,11 @@ > > > > > > > > > > > #include > > > > > > > > > > > #include > > > > > > > > > > > #include > > > > > > > > > > > +#include > > > > > > > > > > > #include > > > > > > > > > > > > > > > > > > > > > > #include > > > > > > > > > > > +#include > > > > > > > > > > > #include > > > > > > > > > > > #include > > > > > > > > > > > > > > > > > > > > > > @@ -569,7 +571,6 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext); > > > > > > > > > > > > > > > > > > > > > > /** > > > > > > > > > > > * drm_sched_job_init - init a scheduler job > > > > > > > > > > > - * > > > > > > > > > > > * @job: scheduler job to init > > > > > > > > > > > * @entity: scheduler entity to use > > > > > > > > > > > * @owner: job owner for debugging > > > > > > > > > > > @@ -577,6 +578,9 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext); > > > > > > > > > > > * Refer to drm_sched_entity_push_job() documentation > > > > > > > > > > > * for locking considerations. > > > > > > > > > > > * > > > > > > > > > > > + * Drivers must make sure drm_sched_job_cleanup() if this function returns > > > > > > > > > > > + * successfully, even when @job is aborted before drm_sched_job_arm() is called. > > > > > > > > > > > + * > > > > > > > > > > > * Returns 0 for success, negative error code otherwise. > > > > > > > > > > > */ > > > > > > > > > > > int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > @@ -594,7 +598,7 @@ int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > job->sched = sched; > > > > > > > > > > > job->entity = entity; > > > > > > > > > > > job->s_priority = entity->rq - sched->sched_rq; > > > > > > > > > > > - job->s_fence = drm_sched_fence_create(entity, owner); > > > > > > > > > > > + job->s_fence = drm_sched_fence_alloc(entity, owner); > > > > > > > > > > > if (!job->s_fence) > > > > > > > > > > > return -ENOMEM; > > > > > > > > > > > job->id = atomic64_inc_return(&sched->job_id_count); > > > > > > > > > > > @@ -606,13 +610,47 @@ int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > EXPORT_SYMBOL(drm_sched_job_init); > > > > > > > > > > > > > > > > > > > > > > /** > > > > > > > > > > > - * drm_sched_job_cleanup - clean up scheduler job resources > > > > > > > > > > > + * drm_sched_job_arm - arm a scheduler job for execution > > > > > > > > > > > + * @job: scheduler job to arm > > > > > > > > > > > + * > > > > > > > > > > > + * This arms a scheduler job for execution. Specifically it initializes the > > > > > > > > > > > + * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv > > > > > > > > > > > + * or other places that need to track the completion of this job. > > > > > > > > > > > + * > > > > > > > > > > > + * Refer to drm_sched_entity_push_job() documentation for locking > > > > > > > > > > > + * considerations. > > > > > > > > > > > * > > > > > > > > > > > + * This can only be called if drm_sched_job_init() succeeded. > > > > > > > > > > > + */ > > > > > > > > > > > +void drm_sched_job_arm(struct drm_sched_job *job) > > > > > > > > > > > +{ > > > > > > > > > > > + drm_sched_fence_init(job->s_fence, job->entity); > > > > > > > > > > > +} > > > > > > > > > > > +EXPORT_SYMBOL(drm_sched_job_arm); > > > > > > > > > > > + > > > > > > > > > > > +/** > > > > > > > > > > > + * drm_sched_job_cleanup - clean up scheduler job resources > > > > > > > > > > > * @job: scheduler job to clean up > > > > > > > > > > > + * > > > > > > > > > > > + * Cleans up the resources allocated with drm_sched_job_init(). > > > > > > > > > > > + * > > > > > > > > > > > + * Drivers should call this from their error unwind code if @job is aborted > > > > > > > > > > > + * before drm_sched_job_arm() is called. > > > > > > > > > > > + * > > > > > > > > > > > + * After that point of no return @job is committed to be executed by the > > > > > > > > > > > + * scheduler, and this function should be called from the > > > > > > > > > > > + * &drm_sched_backend_ops.free_job callback. > > > > > > > > > > > */ > > > > > > > > > > > void drm_sched_job_cleanup(struct drm_sched_job *job) > > > > > > > > > > > { > > > > > > > > > > > - dma_fence_put(&job->s_fence->finished); > > > > > > > > > > > + if (!kref_read(&job->s_fence->finished.refcount)) { > > > > > > > > > > > + /* drm_sched_job_arm() has been called */ > > > > > > > > > > > + dma_fence_put(&job->s_fence->finished); > > > > > > > > > > > + } else { > > > > > > > > > > > + /* aborted job before committing to run it */ > > > > > > > > > > > + drm_sched_fence_free(&job->s_fence->finished.rcu); > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > job->s_fence = NULL; > > > > > > > > > > > } > > > > > > > > > > > EXPORT_SYMBOL(drm_sched_job_cleanup); > > > > > > > > > > > diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c > > > > > > > > > > > index 4eb354226972..5c3a99027ecd 100644 > > > > > > > > > > > --- a/drivers/gpu/drm/v3d/v3d_gem.c > > > > > > > > > > > +++ b/drivers/gpu/drm/v3d/v3d_gem.c > > > > > > > > > > > @@ -475,6 +475,8 @@ v3d_push_job(struct v3d_file_priv *v3d_priv, > > > > > > > > > > > if (ret) > > > > > > > > > > > return ret; > > > > > > > > > > > > > > > > > > > > > > + drm_sched_job_arm(&job->base); > > > > > > > > > > > + > > > > > > > > > > > job->done_fence = dma_fence_get(&job->base.s_fence->finished); > > > > > > > > > > > > > > > > > > > > > > /* put by scheduler job completion */ > > > > > > > > > > > diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h > > > > > > > > > > > index 88ae7f331bb1..83afc3aa8e2f 100644 > > > > > > > > > > > --- a/include/drm/gpu_scheduler.h > > > > > > > > > > > +++ b/include/drm/gpu_scheduler.h > > > > > > > > > > > @@ -348,6 +348,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched); > > > > > > > > > > > int drm_sched_job_init(struct drm_sched_job *job, > > > > > > > > > > > struct drm_sched_entity *entity, > > > > > > > > > > > void *owner); > > > > > > > > > > > +void drm_sched_job_arm(struct drm_sched_job *job); > > > > > > > > > > > void drm_sched_entity_modify_sched(struct drm_sched_entity *entity, > > > > > > > > > > > struct drm_gpu_scheduler **sched_list, > > > > > > > > > > > unsigned int num_sched_list); > > > > > > > > > > > @@ -387,8 +388,12 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity, > > > > > > > > > > > enum drm_sched_priority priority); > > > > > > > > > > > bool drm_sched_entity_is_ready(struct drm_sched_entity *entity); > > > > > > > > > > > > > > > > > > > > > > -struct drm_sched_fence *drm_sched_fence_create( > > > > > > > > > > > +struct drm_sched_fence *drm_sched_fence_alloc( > > > > > > > > > > > struct drm_sched_entity *s_entity, void *owner); > > > > > > > > > > > +void drm_sched_fence_init(struct drm_sched_fence *fence, > > > > > > > > > > > + struct drm_sched_entity *entity); > > > > > > > > > > > +void drm_sched_fence_free(struct rcu_head *rcu); > > > > > > > > > > > + > > > > > > > > > > > void drm_sched_fence_scheduled(struct drm_sched_fence *fence); > > > > > > > > > > > void drm_sched_fence_finished(struct drm_sched_fence *fence); > > > > > > > > > > > > > > > > > -- > > > Daniel Vetter > > > Software Engineer, Intel Corporation > > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fblog.ffwll.ch%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C1ac51fc78f9f4e2f08a808d941e0c013%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637613255881294371%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=PRGZl6tUAc7FrL39mu%2BBV2AfC02Mz9R2Neqs5TjdB6M%3D&reserved=0 > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fblog.ffwll.ch%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C1ac51fc78f9f4e2f08a808d941e0c013%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637613255881294371%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=PRGZl6tUAc7FrL39mu%2BBV2AfC02Mz9R2Neqs5TjdB6M%3D&reserved=0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch