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 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 BE678C48BCF for ; Wed, 9 Jun 2021 11:28:54 +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 2873161184 for ; Wed, 9 Jun 2021 11:28:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2873161184 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch 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 6FA326E283; Wed, 9 Jun 2021 11:28:53 +0000 (UTC) Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by gabe.freedesktop.org (Postfix) with ESMTPS id F214F89E69 for ; Wed, 9 Jun 2021 11:28:51 +0000 (UTC) Received: by mail-wr1-x435.google.com with SMTP id f2so25032527wri.11 for ; Wed, 09 Jun 2021 04:28:51 -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=DSOZqqxMYrCmbDc/qIrzNxvXXydaoyaAzXzXYYfVSkI=; b=GtiYagN/czC8PTFfjxPmJUKVCSxGWrkylH92NM9tchzJdFsIik4YbJy1F/AvmNJSCz lFoDYsQSXafApm1hU6pb7YffgLVg1fAYD8XaghweyGJvIpXf6xg6S3TKAE8mzNtJDtJV QAC8KuTe8Xp9lVigXcenCOKd7QUAa2ygMp1MA= 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=DSOZqqxMYrCmbDc/qIrzNxvXXydaoyaAzXzXYYfVSkI=; b=r3NVKmHs7nZ5oFjXcpxk7US3Z6vDeAj0/meAOu0JTcrt+DQnmUJBB2KrINa+kVJEH+ K5PjjeT+t2diC1CrbrfA3reBs8mqpuACVtkaTU8i2MaShoDBMAD2vMxI0gXcwJEl4kFG sPqH7+PeqWvL/lvumRfr/XdbZGWt87w2v+qBadqTzz7t8AUMDb7sjR+OzwHBK0G6MXxx bNzNO0EwRv6HIIVrEFd74uIUlJWUCY8bd2YOVKDje3TfJf811sBnPy4IbOseXPL+Tki/ e15riDt3+gYM5N2iQko/Lfs/hsylkRIc3HqBcIPfCTTzf4JmiZOhyakMyCO6TCcnf5AC tyxg== X-Gm-Message-State: AOAM530u19+jxdydJHysFIeENEiC4bpvyBlc6unmMKuKS5WUEKrmadsM Sid72LrkiM95XDCRxjPboK/v0aTz6/NZ3w== X-Google-Smtp-Source: ABdhPJxT/s/1sBRMDUBT6+hf5GKAjdvysChJlnsfCae73xE8svX36sZUjJKTHXEbzZ3j/B5Sy5wQXA== X-Received: by 2002:a05:6000:1a8f:: with SMTP id f15mr19554050wry.260.1623238130403; Wed, 09 Jun 2021 04:28:50 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id q3sm23307019wrr.43.2021.06.09.04.28.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Jun 2021 04:28:49 -0700 (PDT) Date: Wed, 9 Jun 2021 13:28:47 +0200 From: Daniel Vetter To: Jason Ekstrand Subject: Re: [Intel-gfx] [PATCH 16/31] drm/i915/gem: Add an intermediate proto_context struct (v4) Message-ID: References: <20210609043613.102962-1-jason@jlekstrand.net> <20210609043613.102962-17-jason@jlekstrand.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210609043613.102962-17-jason@jlekstrand.net> X-Operating-System: Linux phenom 5.10.32scarlett+ 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@lists.freedesktop.org, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Jun 08, 2021 at 11:35:58PM -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 the engine set are in > 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. > > v2 (Daniel Vetter): > - Better commit message > - Use __set/clear_bit instead of set/clear_bit because there's no race > and we don't need the atomics > > v3 (Daniel Vetter): > - Use manual bitops and BIT() instead of __set_bit > > v4 (Daniel Vetter): > - Add a changelog to the commit message > - Better hyperlinking in docs > - Create the default PPGTT in i915_gem_create_context > > Signed-off-by: Jason Ekstrand > --- > drivers/gpu/drm/i915/gem/i915_gem_context.c | 124 +++++++++++++++--- > .../gpu/drm/i915/gem/i915_gem_context_types.h | 22 ++++ > .../gpu/drm/i915/gem/selftests/mock_context.c | 16 ++- > 3 files changed, 145 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c > index f9a6eac78c0ae..b5d8c1ff5d7b3 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c > @@ -191,6 +191,83 @@ 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; > + > + pc->user_flags |= BIT(UCONTEXT_PERSISTENCE); > + } 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; > + > + pc->user_flags &= ~BIT(UCONTEXT_PERSISTENCE); > + } > + > + 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); > + > + pc->user_flags = BIT(UCONTEXT_BANNABLE) | > + BIT(UCONTEXT_RECOVERABLE); > + proto_context_set_persistence(i915, pc, true); I think we're down to the bikeshed here that I think should be open-coded for clarity of what exactly is going on. But maybe better in a distinct patch. Reviewed-by: Daniel Vetter > + 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 +737,8 @@ 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 +751,7 @@ __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 +774,7 @@ __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; > @@ -786,20 +862,22 @@ 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)) { > + if (pc->vm) { > + /* __assign_ppgtt() requires this mutex to be held */ > + mutex_lock(&ctx->mutex); > + __assign_ppgtt(ctx, pc->vm); > + mutex_unlock(&ctx->mutex); > + } else if (HAS_FULL_PPGTT(i915)) { > struct i915_ppgtt *ppgtt; > > ppgtt = i915_ppgtt_create(&i915->gt); > @@ -810,14 +888,16 @@ i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) > return ERR_CAST(ppgtt); > } > > + /* __assign_ppgtt() requires this mutex to be held */ > mutex_lock(&ctx->mutex); > __assign_ppgtt(ctx, &ppgtt->vm); > mutex_unlock(&ctx->mutex); > > + /* __assign_ppgtt() takes another reference for us */ > 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 +963,7 @@ 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 +973,14 @@ 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 +1972,7 @@ 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 +1995,12 @@ 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..e0bdf3e298a6a 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 > + * a struct i915_gem_context. This is used to gather parameters provided > + * either 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 */ > + 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