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_SIGNED, DKIM_VALID,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 A54DCC4708F for ; Wed, 2 Jun 2021 21:24:56 +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 4FBB0613E7 for ; Wed, 2 Jun 2021 21:24:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4FBB0613E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jlekstrand.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A7C6D6EE6A; Wed, 2 Jun 2021 21:24:55 +0000 (UTC) Received: from mail-yb1-xb35.google.com (mail-yb1-xb35.google.com [IPv6:2607:f8b0:4864:20::b35]) by gabe.freedesktop.org (Postfix) with ESMTPS id CE8CF6EE74 for ; Wed, 2 Jun 2021 21:24:54 +0000 (UTC) Received: by mail-yb1-xb35.google.com with SMTP id y2so5760992ybq.13 for ; Wed, 02 Jun 2021 14:24:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jlekstrand-net.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=G51rildGrc4KjQJB/eWXCtw0VzLC7Z6eZIMi/Wu0Vuk=; b=FqC/V2E90xYtcxZTxkeOG06MEjaTWq8KOtiO4mSpncUzDvxratrbgkoSR6gP+uP/MF inZ2XR9fHxLzPIm+SiHLXKSQOzOQ9xTdC3TGcOhCv3ImiMYbIHr36IK7LevXH90Syhqc dl5NiOX/XCsoifv/x5Ww2XYwBk/H7O03elYbqW7YmLuCa8wKJHPtX3C9Pz+kM5LVfYbQ EW0+UGvOWJASNoQlnxtqt4/dzcZ9cA7UaLcqbog8pnuTx01vyu5r6ESLw6pZa7Ngi9oW d7CH5U260nwo86oiB1svah6jTomWG/Mi/8d4NT3LYypvke/Bq5QIkqqQFfKqEzW5n/eP M++w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=G51rildGrc4KjQJB/eWXCtw0VzLC7Z6eZIMi/Wu0Vuk=; b=ArDFv7RweV9DvtJZcJ/8F606U2yjio/AIzE2DVwYLLM5GyLCmoMyFxUe6/N961QnAO Gcplbnxlx0wU179jfpLkrm/xa6VWt2duW3LqQUb7iRbvlzzPqQ+9HK9Fh67ZiQGCjJPy AobnL5h20RNZGbDC4KEGQHAlP5GHaI2oDWU0kdQrZ46n8OvMvb5UQBIdvcQ4yHKMvLKu Ul+Q/Q69FwlLi8U6sJ5WRyrhxP/E1JALdVXeTNP7S+M2dr2mEh2rPJzHB03BpUrxXn7b w2VrMZQ32Q3fmS6Df/Ov20r2YEE0KbN26cASmm+izzUq6BnNcOhNrcBFSrpEEKEdBk4x y0DQ== X-Gm-Message-State: AOAM531K6Bi6J99RnideAVOaUWrCBHx0dLh2OLrzS+M2fUKUfW7XBNYX hXtJo6z634k5OwHPTZKVSzUJxXkWSTMjB/CzDACdFw== X-Google-Smtp-Source: ABdhPJyAxN9UT6PSvaT2XsuegpQIhKe2bZJLIOS/tF6O0OLhOisLKsJ360b94Hu2gkwFNkIgVyEuEP26Vkfe3a6kroY= X-Received: by 2002:a25:3415:: with SMTP id b21mr13439619yba.241.1622669093656; Wed, 02 Jun 2021 14:24:53 -0700 (PDT) MIME-Version: 1.0 References: <20210527162650.1182544-1-jason@jlekstrand.net> <20210527162650.1182544-17-jason@jlekstrand.net> In-Reply-To: From: Jason Ekstrand Date: Wed, 2 Jun 2021 16:24:42 -0500 Message-ID: Subject: Re: [Intel-gfx] [PATCH 16/29] drm/i915/gem: Add an intermediate proto_context struct To: Daniel Vetter Content-Type: text/plain; charset="UTF-8" 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: Intel GFX , Maling list - DRI developers Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, May 31, 2021 at 3:47 AM Daniel Vetter wrote: > > On Thu, May 27, 2021 at 11:26:37AM -0500, Jason Ekstrand wrote: > > The current context uAPI allows for two methods of setting context > > parameters: SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM. The > > former is allowed to be called at any time while the later happens as > > part of GEM_CONTEXT_CREATE. Currently, everything settable via one is > > settable via the other. While some params are fairly simple and setting > > them on a live context is harmless such the context priority, others are > > far trickier such as the VM or the set of engines. In order to swap out > > the VM, for instance, we have to delay until all current in-flight work > > is complete, swap in the new VM, and then continue. This leads to a > > plethora of potential race conditions we'd really rather avoid. > > > > Unfortunately, both methods of setting the VM and engine set are in > > ^the > > At least my English parser jumped there a bit and got confused :-) I believe what I wrote was correct but I'm happy to tweak it if it helps others' parsers. > > active use today so we can't simply disallow setting the VM or engine > > set vial SET_CONTEXT_PARAM. In order to work around this wart, this > > commit adds a proto-context struct which contains all the context create > > parameters. > > > > Signed-off-by: Jason Ekstrand > > I also looked at my review from the previous round and I think we have a > few opens there that haven't been addressed here. Would be nice to check > that out too and my reply there if you're disagreeing and want to paint > the shed differently :-) Ok, I'll try to dig it up. I miss GitLab and it's "resolve discussion" button so much.... > I've found a few other things needing polish below on top of the earlier > bits. > -Daniel > > > --- > > drivers/gpu/drm/i915/gem/i915_gem_context.c | 145 ++++++++++++++---- > > .../gpu/drm/i915/gem/i915_gem_context_types.h | 22 +++ > > .../gpu/drm/i915/gem/selftests/mock_context.c | 16 +- > > 3 files changed, 153 insertions(+), 30 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c > > index fc471243aa769..10bff488444b6 100644 > > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c > > @@ -191,6 +191,97 @@ static int validate_priority(struct drm_i915_private *i915, > > return 0; > > } > > > > +static void proto_context_close(struct i915_gem_proto_context *pc) > > +{ > > + if (pc->vm) > > + i915_vm_put(pc->vm); > > + kfree(pc); > > +} > > + > > +static int proto_context_set_persistence(struct drm_i915_private *i915, > > + struct i915_gem_proto_context *pc, > > + bool persist) > > +{ > > + if (persist) { > > + /* > > + * Only contexts that are short-lived [that will expire or be > > + * reset] are allowed to survive past termination. We require > > + * hangcheck to ensure that the persistent requests are healthy. > > + */ > > + if (!i915->params.enable_hangcheck) > > + return -EINVAL; > > + > > + __set_bit(UCONTEXT_PERSISTENCE, &pc->user_flags); > > + } else { > > + /* To cancel a context we use "preempt-to-idle" */ > > + if (!(i915->caps.scheduler & I915_SCHEDULER_CAP_PREEMPTION)) > > + return -ENODEV; > > + > > + /* > > + * If the cancel fails, we then need to reset, cleanly! > > + * > > + * If the per-engine reset fails, all hope is lost! We resort > > + * to a full GPU reset in that unlikely case, but realistically > > + * if the engine could not reset, the full reset does not fare > > + * much better. The damage has been done. > > + * > > + * However, if we cannot reset an engine by itself, we cannot > > + * cleanup a hanging persistent context without causing > > + * colateral damage, and we should not pretend we can by > > + * exposing the interface. > > + */ > > + if (!intel_has_reset_engine(&i915->gt)) > > + return -ENODEV; > > + > > + __clear_bit(UCONTEXT_PERSISTENCE, &pc->user_flags); > > + } > > + > > + return 0; > > +} > > + > > +static struct i915_gem_proto_context * > > +proto_context_create(struct drm_i915_private *i915, unsigned int flags) > > +{ > > + struct i915_gem_proto_context *pc, *err; > > + > > + pc = kzalloc(sizeof(*pc), GFP_KERNEL); > > + if (!pc) > > + return ERR_PTR(-ENOMEM); > > + > > + if (HAS_FULL_PPGTT(i915)) { > > + struct i915_ppgtt *ppgtt; > > + > > + ppgtt = i915_ppgtt_create(&i915->gt); > > + if (IS_ERR(ppgtt)) { > > + drm_dbg(&i915->drm, "PPGTT setup failed (%ld)\n", > > + PTR_ERR(ppgtt)); > > + err = ERR_CAST(ppgtt); > > + goto proto_close; > > + } > > + pc->vm = &ppgtt->vm; > > + } > > + > > + pc->user_flags = 0; > > + __set_bit(UCONTEXT_BANNABLE, &pc->user_flags); > > + __set_bit(UCONTEXT_RECOVERABLE, &pc->user_flags); > > + proto_context_set_persistence(i915, pc, true); > > You've lost the error handling here. No, I've not. This is where that helper is both wonderful and crazy annoying. We could have a helper to check whether or not a particular persistence setting is allowed. Instead (and this is what the old code does too), it's initialized to false by kzalloc and then we try to set it to true and ignore the failure. This ensures that, regardless of which options are allowed, we'll end up with an allowed one. Yeah, the more I type here the more I realize just how bad of an idea that is. :-) If you'd like, we can refactor things to have a validation function persistence_setting_valid() or maybe a pair requires_persistence() and persistence_allowed(). I'm open to other suggestions too. > > + pc->sched.priority = I915_PRIORITY_NORMAL; > > + > > + if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE) { > > + if (!HAS_EXECLISTS(i915)) { > > + err = ERR_PTR(-EINVAL); > > + goto proto_close; > > + } > > + pc->single_timeline = true; > > + } > > + > > + return pc; > > + > > +proto_close: > > + proto_context_close(pc); > > + return err; > > +} > > + > > static struct i915_address_space * > > context_get_vm_rcu(struct i915_gem_context *ctx) > > { > > @@ -660,7 +751,8 @@ static int __context_set_persistence(struct i915_gem_context *ctx, bool state) > > } > > > > static struct i915_gem_context * > > -__create_context(struct drm_i915_private *i915) > > +__create_context(struct drm_i915_private *i915, > > + const struct i915_gem_proto_context *pc) > > { > > struct i915_gem_context *ctx; > > struct i915_gem_engines *e; > > @@ -673,7 +765,7 @@ __create_context(struct drm_i915_private *i915) > > > > kref_init(&ctx->ref); > > ctx->i915 = i915; > > - ctx->sched.priority = I915_PRIORITY_NORMAL; > > + ctx->sched = pc->sched; > > mutex_init(&ctx->mutex); > > INIT_LIST_HEAD(&ctx->link); > > > > @@ -696,9 +788,7 @@ __create_context(struct drm_i915_private *i915) > > * is no remap info, it will be a NOP. */ > > ctx->remap_slice = ALL_L3_SLICES(i915); > > > > - i915_gem_context_set_bannable(ctx); > > - i915_gem_context_set_recoverable(ctx); > > - __context_set_persistence(ctx, true /* cgroup hook? */); > > + ctx->user_flags = pc->user_flags; > > > > for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp); i++) > > ctx->hang_timestamp[i] = jiffies - CONTEXT_FAST_HANG_JIFFIES; > > @@ -786,38 +876,23 @@ static void __assign_ppgtt(struct i915_gem_context *ctx, > > } > > > > static struct i915_gem_context * > > -i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) > > +i915_gem_create_context(struct drm_i915_private *i915, > > + const struct i915_gem_proto_context *pc) > > { > > struct i915_gem_context *ctx; > > int ret; > > > > - if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE && > > - !HAS_EXECLISTS(i915)) > > - return ERR_PTR(-EINVAL); > > - > > - ctx = __create_context(i915); > > + ctx = __create_context(i915, pc); > > if (IS_ERR(ctx)) > > return ctx; > > > > - if (HAS_FULL_PPGTT(i915)) { > > - struct i915_ppgtt *ppgtt; > > - > > - ppgtt = i915_ppgtt_create(&i915->gt); > > - if (IS_ERR(ppgtt)) { > > - drm_dbg(&i915->drm, "PPGTT setup failed (%ld)\n", > > - PTR_ERR(ppgtt)); > > - context_close(ctx); > > - return ERR_CAST(ppgtt); > > - } > > - > > + if (pc->vm) { > > mutex_lock(&ctx->mutex); > > - __assign_ppgtt(ctx, &ppgtt->vm); > > + __assign_ppgtt(ctx, pc->vm); > > mutex_unlock(&ctx->mutex); > > - > > - i915_vm_put(&ppgtt->vm); > > } > > > > - if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE) { > > + if (pc->single_timeline) { > > ret = drm_syncobj_create(&ctx->syncobj, > > DRM_SYNCOBJ_CREATE_SIGNALED, > > NULL); > > @@ -883,6 +958,7 @@ int i915_gem_context_open(struct drm_i915_private *i915, > > struct drm_file *file) > > { > > struct drm_i915_file_private *file_priv = file->driver_priv; > > + struct i915_gem_proto_context *pc; > > struct i915_gem_context *ctx; > > int err; > > u32 id; > > @@ -892,7 +968,14 @@ int i915_gem_context_open(struct drm_i915_private *i915, > > /* 0 reserved for invalid/unassigned ppgtt */ > > xa_init_flags(&file_priv->vm_xa, XA_FLAGS_ALLOC1); > > > > - ctx = i915_gem_create_context(i915, 0); > > + pc = proto_context_create(i915, 0); > > + if (IS_ERR(pc)) { > > + err = PTR_ERR(pc); > > + goto err; > > + } > > + > > + ctx = i915_gem_create_context(i915, pc); > > + proto_context_close(pc); > > if (IS_ERR(ctx)) { > > err = PTR_ERR(ctx); > > goto err; > > @@ -1884,6 +1967,7 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data, > > { > > struct drm_i915_private *i915 = to_i915(dev); > > struct drm_i915_gem_context_create_ext *args = data; > > + struct i915_gem_proto_context *pc; > > struct create_ext ext_data; > > int ret; > > u32 id; > > @@ -1906,7 +1990,12 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data, > > return -EIO; > > } > > > > - ext_data.ctx = i915_gem_create_context(i915, args->flags); > > + pc = proto_context_create(i915, args->flags); > > + if (IS_ERR(pc)) > > + return PTR_ERR(pc); > > + > > + ext_data.ctx = i915_gem_create_context(i915, pc); > > + proto_context_close(pc); > > if (IS_ERR(ext_data.ctx)) > > return PTR_ERR(ext_data.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 5f0673a2129f9..0bf337b6d89ac 100644 > > --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h > > @@ -66,6 +66,28 @@ struct i915_gem_engines_iter { > > const struct i915_gem_engines *engines; > > }; > > > > +/** > > + * struct i915_gem_proto_context - prototype context > > + * > > + * The struct i915_gem_proto_context represents the creation parameters for > > + * an i915_gem_context. This is used to gather parameters provided either > > a struct i915_gem_context Done. > With that you get an automatic neat hyperlink. See > > https://dri.freedesktop.org/docs/drm/doc-guide/kernel-doc.html#highlights-and-cross-references > > for what it all recognizes automatically. > > > + * through creation flags or via SET_CONTEXT_PARAM so that, when we create > > + * the final i915_gem_context, those parameters can be immutable. > > + */ > > +struct i915_gem_proto_context { > > + /** @vm: See i915_gem_context::vm */ > > Hyperlinks need &i915_gem_context.vm in kerneldoc. Same for the others > below. Fixed. I'll try to dig through your previous one now. I thought I'd gotten everything but clearly you found something I hadn't. --Jason > > + struct i915_address_space *vm; > > + > > + /** @user_flags: See i915_gem_context::user_flags */ > > + unsigned long user_flags; > > + > > + /** @sched: See i915_gem_context::sched */ > > + struct i915_sched_attr sched; > > + > > + /** @single_timeline: See See i915_gem_context::syncobj */ > > + bool single_timeline; > > +}; > > + > > /** > > * struct i915_gem_context - client state > > * > > diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c > > index 51b5a3421b400..e0f512ef7f3c6 100644 > > --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c > > +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c > > @@ -80,11 +80,17 @@ void mock_init_contexts(struct drm_i915_private *i915) > > struct i915_gem_context * > > live_context(struct drm_i915_private *i915, struct file *file) > > { > > + struct i915_gem_proto_context *pc; > > struct i915_gem_context *ctx; > > int err; > > u32 id; > > > > - ctx = i915_gem_create_context(i915, 0); > > + pc = proto_context_create(i915, 0); > > + if (IS_ERR(pc)) > > + return ERR_CAST(pc); > > + > > + ctx = i915_gem_create_context(i915, pc); > > + proto_context_close(pc); > > if (IS_ERR(ctx)) > > return ctx; > > > > @@ -142,8 +148,14 @@ struct i915_gem_context * > > kernel_context(struct drm_i915_private *i915) > > { > > struct i915_gem_context *ctx; > > + struct i915_gem_proto_context *pc; > > + > > + pc = proto_context_create(i915, 0); > > + if (IS_ERR(pc)) > > + return ERR_CAST(pc); > > > > - ctx = i915_gem_create_context(i915, 0); > > + ctx = i915_gem_create_context(i915, pc); > > + proto_context_close(pc); > > if (IS_ERR(ctx)) > > return ctx; > > > > -- > > 2.31.1 > > > > _______________________________________________ > > 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