From d63763749127b483ba042b2939ba39fd79792330 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 7 Feb 2018 21:05:44 +0000 Subject: [PATCH] drm/i915: Only allocate preempt context when required If we remove some hardcoded assumptions about the preempt context having a fixed id, reserved from use by normal user contexts, we may only allocate the i915_gem_context when required. Then the subsequent decisions on using preemption reduce to having the preempt context available. v2: Include an assert that we don't allocate the preempt context twice. Signed-off-by: Chris Wilson Cc: Michal Winiarski Cc: Tvrtko Ursulin Cc: Arkadiusz Hiler Cc: Mika Kuoppala Cc: Daniele Ceraolo Spurio Acked-by: Daniele Ceraolo Spurio Link: https://patchwork.freedesktop.org/patch/msgid/20180207210544.26351-3-chris@chris-wilson.co.uk Reviewed-by: Michel Thierry --- drivers/gpu/drm/i915/i915_gem_context.c | 31 ++++++++++--------- drivers/gpu/drm/i915/intel_engine_cs.c | 6 ++-- drivers/gpu/drm/i915/intel_guc_submission.c | 24 +++++++------- drivers/gpu/drm/i915/intel_lrc.c | 17 ++++++---- drivers/gpu/drm/i915/intel_ringbuffer.h | 5 +++ .../gpu/drm/i915/selftests/mock_gem_device.c | 6 ---- 6 files changed, 48 insertions(+), 41 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index 8337d15bb0e5..dd9efb9d0e0b 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -449,12 +449,18 @@ destroy_kernel_context(struct i915_gem_context **ctxp) i915_gem_context_free(ctx); } +static bool needs_preempt_context(struct drm_i915_private *i915) +{ + return HAS_LOGICAL_RING_PREEMPTION(i915); +} + int i915_gem_contexts_init(struct drm_i915_private *dev_priv) { struct i915_gem_context *ctx; - int err; + /* Reassure ourselves we are only called once */ GEM_BUG_ON(dev_priv->kernel_context); + GEM_BUG_ON(dev_priv->preempt_context); INIT_LIST_HEAD(&dev_priv->contexts.list); INIT_WORK(&dev_priv->contexts.free_work, contexts_free_worker); @@ -468,8 +474,7 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv) ctx = i915_gem_context_create_kernel(dev_priv, I915_PRIORITY_MIN); if (IS_ERR(ctx)) { DRM_ERROR("Failed to create default global context\n"); - err = PTR_ERR(ctx); - goto err; + return PTR_ERR(ctx); } /* * For easy recognisablity, we want the kernel context to be 0 and then @@ -479,23 +484,18 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv) dev_priv->kernel_context = ctx; /* highest priority; preempting task */ - ctx = i915_gem_context_create_kernel(dev_priv, INT_MAX); - if (IS_ERR(ctx)) { - DRM_ERROR("Failed to create default preempt context\n"); - err = PTR_ERR(ctx); - goto err_kernel_context; + if (needs_preempt_context(dev_priv)) { + ctx = i915_gem_context_create_kernel(dev_priv, INT_MAX); + if (!IS_ERR(ctx)) + dev_priv->preempt_context = ctx; + else + DRM_ERROR("Failed to create preempt context; disabling preemption\n"); } - dev_priv->preempt_context = ctx; DRM_DEBUG_DRIVER("%s context support initialized\n", dev_priv->engine[RCS]->context_size ? "logical" : "fake"); return 0; - -err_kernel_context: - destroy_kernel_context(&dev_priv->kernel_context); -err: - return err; } void i915_gem_contexts_lost(struct drm_i915_private *dev_priv) @@ -521,7 +521,8 @@ void i915_gem_contexts_fini(struct drm_i915_private *i915) { lockdep_assert_held(&i915->drm.struct_mutex); - destroy_kernel_context(&i915->preempt_context); + if (i915->preempt_context) + destroy_kernel_context(&i915->preempt_context); destroy_kernel_context(&i915->kernel_context); /* Must free all deferred contexts (via flush_workqueue) first */ diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index 7eebfbb95e89..bf634432c9c6 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -631,7 +631,7 @@ int intel_engine_init_common(struct intel_engine_cs *engine) * Similarly the preempt context must always be available so that * we can interrupt the engine at any time. */ - if (HAS_LOGICAL_RING_PREEMPTION(engine->i915)) { + if (engine->i915->preempt_context) { ring = engine->context_pin(engine, engine->i915->preempt_context); if (IS_ERR(ring)) { @@ -656,7 +656,7 @@ int intel_engine_init_common(struct intel_engine_cs *engine) err_breadcrumbs: intel_engine_fini_breadcrumbs(engine); err_unpin_preempt: - if (HAS_LOGICAL_RING_PREEMPTION(engine->i915)) + if (engine->i915->preempt_context) engine->context_unpin(engine, engine->i915->preempt_context); err_unpin_kernel: engine->context_unpin(engine, engine->i915->kernel_context); @@ -686,7 +686,7 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine) if (engine->default_state) i915_gem_object_put(engine->default_state); - if (HAS_LOGICAL_RING_PREEMPTION(engine->i915)) + if (engine->i915->preempt_context) engine->context_unpin(engine, engine->i915->preempt_context); engine->context_unpin(engine, engine->i915->kernel_context); } diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c index 4ea65df05e02..b43b58cc599b 100644 --- a/drivers/gpu/drm/i915/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/intel_guc_submission.c @@ -688,7 +688,7 @@ static void guc_dequeue(struct intel_engine_cs *engine) goto unlock; if (port_isset(port)) { - if (HAS_LOGICAL_RING_PREEMPTION(engine->i915)) { + if (engine->i915->preempt_context) { struct guc_preempt_work *preempt_work = &engine->i915->guc.preempt_work[engine->id]; @@ -984,17 +984,19 @@ static int guc_clients_create(struct intel_guc *guc) } guc->execbuf_client = client; - client = guc_client_alloc(dev_priv, - INTEL_INFO(dev_priv)->ring_mask, - GUC_CLIENT_PRIORITY_KMD_HIGH, - dev_priv->preempt_context); - if (IS_ERR(client)) { - DRM_ERROR("Failed to create GuC client for preemption!\n"); - guc_client_free(guc->execbuf_client); - guc->execbuf_client = NULL; - return PTR_ERR(client); + if (dev_priv->preempt_context) { + client = guc_client_alloc(dev_priv, + INTEL_INFO(dev_priv)->ring_mask, + GUC_CLIENT_PRIORITY_KMD_HIGH, + dev_priv->preempt_context); + if (IS_ERR(client)) { + DRM_ERROR("Failed to create GuC client for preemption!\n"); + guc_client_free(guc->execbuf_client); + guc->execbuf_client = NULL; + return PTR_ERR(client); + } + guc->preempt_client = client; } - guc->preempt_client = client; return 0; } diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 449fd1e95f1f..c2c8380a0121 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -161,7 +161,6 @@ #define EXECLISTS_REQUEST_SIZE 64 /* bytes */ #define WA_TAIL_DWORDS 2 #define WA_TAIL_BYTES (sizeof(u32) * WA_TAIL_DWORDS) -#define PREEMPT_ID 0x1 static int execlists_context_deferred_alloc(struct i915_gem_context *ctx, struct intel_engine_cs *engine); @@ -448,7 +447,8 @@ static void inject_preempt_context(struct intel_engine_cs *engine) &engine->i915->preempt_context->engine[engine->id]; unsigned int n; - GEM_BUG_ON(engine->i915->preempt_context->hw_id != PREEMPT_ID); + GEM_BUG_ON(engine->execlists.preempt_complete_status != + upper_32_bits(ce->lrc_desc)); GEM_BUG_ON(!IS_ALIGNED(ce->ring->size, WA_TAIL_BYTES)); memset(ce->ring->vaddr + ce->ring->tail, 0, WA_TAIL_BYTES); @@ -528,7 +528,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_HWACK)) goto unlock; - if (HAS_LOGICAL_RING_PREEMPTION(engine->i915) && + if (engine->i915->preempt_context && rb_entry(rb, struct i915_priolist, node)->priority > max(last->priotree.priority, 0)) { /* @@ -844,7 +844,7 @@ static void execlists_submission_tasklet(unsigned long data) GEM_BUG_ON(status & GEN8_CTX_STATUS_IDLE_ACTIVE); if (status & GEN8_CTX_STATUS_COMPLETE && - buf[2*head + 1] == PREEMPT_ID) { + buf[2*head + 1] == execlists->preempt_complete_status) { GEM_TRACE("%s preempt-idle\n", engine->name); execlists_cancel_port_requests(execlists); @@ -1967,7 +1967,7 @@ static void execlists_set_default_submission(struct intel_engine_cs *engine) engine->i915->caps.scheduler = I915_SCHEDULER_CAP_ENABLED | I915_SCHEDULER_CAP_PRIORITY; - if (HAS_LOGICAL_RING_PREEMPTION(engine->i915)) + if (engine->i915->preempt_context) engine->i915->caps.scheduler |= I915_SCHEDULER_CAP_PREEMPTION; } @@ -2045,6 +2045,11 @@ static int logical_ring_init(struct intel_engine_cs *engine) engine->execlists.elsp = engine->i915->regs + i915_mmio_reg_offset(RING_ELSP(engine)); + engine->execlists.preempt_complete_status = ~0u; + if (engine->i915->preempt_context) + engine->execlists.preempt_complete_status = + upper_32_bits(engine->i915->preempt_context->engine[engine->id].lrc_desc); + return 0; error: @@ -2307,7 +2312,7 @@ populate_lr_context(struct i915_gem_context *ctx, if (!engine->default_state) regs[CTX_CONTEXT_CONTROL + 1] |= _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT); - if (ctx->hw_id == PREEMPT_ID) + if (ctx == ctx->i915->preempt_context) regs[CTX_CONTEXT_CONTROL + 1] |= _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT | CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT); diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index a0e7a6c2a57c..8f1a4badf812 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -279,6 +279,11 @@ struct intel_engine_execlists { * @csb_use_mmio: access csb through mmio, instead of hwsp */ bool csb_use_mmio; + + /** + * @preempt_complete_status: expected CSB upon completing preemption + */ + u32 preempt_complete_status; }; #define INTEL_ENGINE_CS_MAX_NAME 8 diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c index 1bc61f3f76fc..3175db70cc6e 100644 --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c @@ -243,16 +243,10 @@ struct drm_i915_private *mock_gem_device(void) if (!i915->kernel_context) goto err_engine; - i915->preempt_context = mock_context(i915, NULL); - if (!i915->preempt_context) - goto err_kernel_context; - WARN_ON(i915_gemfs_init(i915)); return i915; -err_kernel_context: - i915_gem_context_put(i915->kernel_context); err_engine: for_each_engine(engine, i915, id) mock_engine_free(engine); -- 2.30.2