Agree, but libdrm doesn't allow concurrent submissions from same context, like protection 'pthread_mutex_lock(&context->sequence_mutex);' in amdgpu_cs_submit_one. Regards, David Zhou On 2017å¹´04æ??28æ?¥ 16:15, Christian König wrote: > Indeed, but after a bit of thinking I've found another problem with > that patch. > > When two threads are pushing jobs into the same scheduler context we > don't guarantee correct execution order any more! > > Before that patch it was handled by the exclusiveness we had because > of reserving the VM page tables, but now nothing prevents us from > calling amd_sched_entity_push_job() in nondeterministic order. > > In other words we need an additional lock in amdgpu_ctx_ring or > something like that. > > Regards, > Christian. > > Am 28.04.2017 um 04:51 schrieb Zhang, Jerry: >> Nice catch! >> Reviewed-by: Junwei Zhang <Jerry.Zhang at amd.com> >> >> Regards, >> Jerry (Junwei Zhang) >> >> Linux Base Graphics >> SRDC Software Development >> _____________________________________ >> >> >>> -----Original Message----- >>> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On >>> Behalf Of >>> Chunming Zhou >>> Sent: Friday, April 28, 2017 10:46 >>> To: amd-gfx at lists.freedesktop.org >>> Cc: Zhou, David(ChunMing) >>> Subject: [PATCH] drm/amdgpu: fix deadlock of reservation between cs >>> and gpu >>> reset v2 >>> >>> the case could happen when gpu reset: >>> 1. when gpu reset, cs can be continue until sw queue is full, then >>> push job will >>> wait with holding pd reservation. >>> 2. gpu_reset routine will also need pd reservation to restore page >>> table from >>> their shadow. >>> 3. cs is waiting for gpu_reset complete, but gpu reset is waiting >>> for cs releases >>> reservation. >>> >>> v2: handle amdgpu_cs_submit error path. >>> >>> Change-Id: I0f66d04b2bef3433035109623c8a5c5992c84202 >>> Signed-off-by: Chunming Zhou <David1.Zhou at amd.com> >>> Reviewed-by: Christian König <christian.koenig at amd.com> >>> Reviewed-by: Junwei Zhang <Jerry.Zhang at amd.com> >>> Reviewed-by: Monk Liu <monk.liu at amd.com> >>> --- >>> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c >>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c >>> index 26168df..699f5fe 100644 >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c >>> @@ -1074,6 +1074,7 @@ static int amdgpu_cs_submit(struct >>> amdgpu_cs_parser >>> *p, >>> cs->out.handle = amdgpu_ctx_add_fence(p->ctx, ring, p->fence); >>> job->uf_sequence = cs->out.handle; >>> amdgpu_job_free_resources(job); >>> + amdgpu_cs_parser_fini(p, 0, true); >>> >>> trace_amdgpu_cs_ioctl(job); >>> amd_sched_entity_push_job(&job->base); >>> @@ -1129,7 +1130,10 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void >>> *data, struct drm_file *filp) >>> goto out; >>> >>> r = amdgpu_cs_submit(&parser, cs); >>> + if (r) >>> + goto out; >>> >>> + return 0; >>> out: >>> amdgpu_cs_parser_fini(&parser, r, reserved_buffers); >>> return r; >>> -- >>> 1.9.1 >>> >>> _______________________________________________ >>> amd-gfx mailing list >>> amd-gfx at lists.freedesktop.org >>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx at lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx > >
