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=-13.6 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=ham 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 2128FC433DB for ; Mon, 22 Mar 2021 16:59:37 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 96C2D61879 for ; Mon, 22 Mar 2021 16:59:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 96C2D61879 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2307E6E120; Mon, 22 Mar 2021 16:59:36 +0000 (UTC) Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by gabe.freedesktop.org (Postfix) with ESMTPS id 082F96E120 for ; Mon, 22 Mar 2021 16:59:34 +0000 (UTC) Received: by mail-wm1-x331.google.com with SMTP id g25so9634576wmh.0 for ; Mon, 22 Mar 2021 09:59:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=As8Z8EnfKpkSbRkP3jx1thKYSjxX4uFIhuJATv1SkHI=; b=fUH2CoGEy+WVnlxlYExWun9Xsi1pFfQxFPg5qpXLBL6tIfMRadmr7UUZVGN7XyTPMc yaofYmnrl05QHc5cYGdySqogabnQkFSt2J06pwlpXxx33V2j1GaMP7ODPDZCZhCEeNcK 0jntvEtLgW5CqEVWLO7xguawySVW5fyA3rItQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=As8Z8EnfKpkSbRkP3jx1thKYSjxX4uFIhuJATv1SkHI=; b=N3/lT34XUF4hAYuOReQt8vniNsKQssjfvASJ3+IxGaF7eRxWaFVRgb/BOlXg5NBa7I 8oTUJEd10aD+KCnCBQd5Gifm7YIoKPye2w8p/YFkQ5Ksis5NHDS9zF35BPTU3lTGEucx NMp9v9NMDp30JWzpVZ1ndVyJpVXDy/mUM0jEgKi4YKVL3H3Xvds1Ugwso2h2bd9qZQyJ Y0J8QKWi1kFUKxCRKDkWDe9twbjqJmZbmho3e5b9DpcVItGCPAm27cOCQyxZFJgdLYBT l+wTUPzAsh4oC6WQeSVoIK6zQqgKxTGjEDC+/NzVukp2otgVyBxPqrlq0nM0w8KbM794 T+sw== X-Gm-Message-State: AOAM530wz63IKXTA7RAsdljw721HHWuvebOq3Bad/qAhoP+2llPuJ42B L70JdYYl9QYchmDf0aUgLbAOqA== X-Google-Smtp-Source: ABdhPJwPzDIgIyGPwSQ6OoWIBt4kBEQj8ubMZtYAH2JL91WunKnQYKEcLKpeUjWo4q3Jr3Y43APCJg== X-Received: by 2002:a1c:7fcd:: with SMTP id a196mr24990wmd.180.1616432373507; Mon, 22 Mar 2021 09:59:33 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id h62sm13209wmf.37.2021.03.22.09.59.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Mar 2021 09:59:32 -0700 (PDT) Date: Mon, 22 Mar 2021 17:59:31 +0100 From: Daniel Vetter To: Jason Ekstrand Message-ID: References: <20210319223856.2983244-1-jason@jlekstrand.net> <20210319223856.2983244-5-jason@jlekstrand.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210319223856.2983244-5-jason@jlekstrand.net> X-Operating-System: Linux phenom 5.7.0-1-amd64 Subject: Re: [Intel-gfx] [PATCH 4/4] drm/i915: Implement SINGLE_TIMELINE with a syncobj X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Fri, Mar 19, 2021 at 05:38:56PM -0500, Jason Ekstrand wrote: > I'd love to delete the SINGLE_TIMELINE API because it leaks an > implementation detail of contexts through to the API and is something > that userspace can do itself, trivially. Unfortunately, it's used by > the media driver so we can't do that. We can, however, do the next-best > thing which is to embed a syncobj in the context and do exactly what > we'd expect from userspace internally. > > This has a couple of advantages. One is that we're no longer leaking a > detail of the current execlist scheduler which will be problematic when > we try to add GuC scheduling. Second is that, together with deleting > the CLONE_CONTEXT API, we should now have a 1:1 mapping between > intel_context and intel_timeline which should make some of our locking > mess a bit easier. > > Signed-off-by: Jason Ekstrand > Cc: Maarten Lankhorst > Cc: Matthew Brost > --- > drivers/gpu/drm/i915/gem/i915_gem_context.c | 47 ++++--------------- > .../gpu/drm/i915/gem/i915_gem_context_types.h | 8 +++- > .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 15 ++++++ > 3 files changed, 32 insertions(+), 38 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c > index f88bac19333ec..e094f4a1ca4cd 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c > @@ -67,6 +67,8 @@ > #include > #include > > +#include > + > #include "gt/gen6_ppgtt.h" > #include "gt/intel_context.h" > #include "gt/intel_engine_heartbeat.h" > @@ -224,10 +226,6 @@ static void intel_context_set_gem(struct intel_context *ce, > ce->vm = vm; > } > > - GEM_BUG_ON(ce->timeline); > - if (ctx->timeline) > - ce->timeline = intel_timeline_get(ctx->timeline); > - > if (ctx->sched.priority >= I915_PRIORITY_NORMAL && > intel_engine_has_timeslices(ce->engine)) > __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags); > @@ -344,8 +342,8 @@ void i915_gem_context_release(struct kref *ref) > mutex_destroy(&ctx->engines_mutex); > mutex_destroy(&ctx->lut_mutex); > > - if (ctx->timeline) > - intel_timeline_put(ctx->timeline); > + if (ctx->syncobj) > + drm_syncobj_put(ctx->syncobj); > > put_pid(ctx->pid); > mutex_destroy(&ctx->mutex); > @@ -790,33 +788,11 @@ static void __assign_ppgtt(struct i915_gem_context *ctx, > i915_vm_close(vm); > } > > -static void __set_timeline(struct intel_timeline **dst, > - struct intel_timeline *src) > -{ > - struct intel_timeline *old = *dst; > - > - *dst = src ? intel_timeline_get(src) : NULL; > - > - if (old) > - intel_timeline_put(old); > -} > - > -static void __apply_timeline(struct intel_context *ce, void *timeline) > -{ > - __set_timeline(&ce->timeline, timeline); > -} > - > -static void __assign_timeline(struct i915_gem_context *ctx, > - struct intel_timeline *timeline) > -{ > - __set_timeline(&ctx->timeline, timeline); > - context_apply_all(ctx, __apply_timeline, timeline); > -} > - > static struct i915_gem_context * > i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) > { > struct i915_gem_context *ctx; > + int ret; > > if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE && > !HAS_EXECLISTS(i915)) > @@ -845,16 +821,13 @@ i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) > } > > if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE) { > - struct intel_timeline *timeline; > - > - timeline = intel_timeline_create(&i915->gt); > - if (IS_ERR(timeline)) { > + ret = drm_syncobj_create(&ctx->syncobj, > + DRM_SYNCOBJ_CREATE_SIGNALED, > + NULL); > + if (ret) { > context_close(ctx); > - return ERR_CAST(timeline); > + return ERR_PTR(ret); > } > - > - __assign_timeline(ctx, timeline); > - intel_timeline_put(timeline); > } > > trace_i915_context_create(ctx); > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h > index 676592e27e7d2..8a5fdd163b79d 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h > @@ -83,7 +83,13 @@ struct i915_gem_context { > struct i915_gem_engines __rcu *engines; > struct mutex engines_mutex; /* guards writes to engines */ > > - struct intel_timeline *timeline; > + /** > + * @syncobj: Shared timeline syncobj > + * > + * When the SHARED_TIMELINE flag is set on context creation, this > + * provides automatic implicit synchronization across all engines. I think we should explain a bit more what this actually does, i.e. emulate it using a syncobj, but unlike the real timeline it does not make any total order guarantees. Since userspace doesn't expect that. > + */ > + struct drm_syncobj *syncobj; > > /** > * @vm: unique address space (GTT) > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c > index 96403130a373d..2c56796f6a71b 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c > @@ -3295,6 +3295,15 @@ i915_gem_do_execbuffer(struct drm_device *dev, > goto err_vma; > } > > + if (eb.gem_context->syncobj) { I think would be good to wrap these in unlikely, least also because it's nice documentation. -Daniel > + struct dma_fence *fence; > + > + fence = drm_syncobj_fence_get(eb.gem_context->syncobj); > + err = i915_request_await_dma_fence(eb.request, fence); > + if (err) > + goto err_ext; > + } > + > if (in_fence) { > if (args->flags & I915_EXEC_FENCE_SUBMIT) > err = i915_request_await_execution(eb.request, > @@ -3351,6 +3360,12 @@ i915_gem_do_execbuffer(struct drm_device *dev, > fput(out_fence->file); > } > } > + > + if (eb.gem_context->syncobj) { > + drm_syncobj_replace_fence(eb.gem_context->syncobj, > + &eb.request->fence); > + } > + > i915_request_put(eb.request); > > err_vma: > -- > 2.29.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx