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=-16.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 B6969C83027 for ; Thu, 2 Sep 2021 16:42:05 +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 56637610D2 for ; Thu, 2 Sep 2021 16:42:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 56637610D2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CBFE66E7D3; Thu, 2 Sep 2021 16:42:01 +0000 (UTC) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by gabe.freedesktop.org (Postfix) with ESMTPS id E211C6E7D2; Thu, 2 Sep 2021 16:41:59 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10095"; a="206305004" X-IronPort-AV: E=Sophos;i="5.85,262,1624345200"; d="scan'208";a="206305004" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2021 09:41:58 -0700 X-IronPort-AV: E=Sophos;i="5.85,262,1624345200"; d="scan'208";a="461754207" Received: from rlsmith2-mobl1.amr.corp.intel.com (HELO [10.213.229.210]) ([10.213.229.210]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2021 09:41:55 -0700 To: Daniel Vetter Cc: Daniel Vetter , DRI Development , Intel Graphics Development , Maarten Lankhorst , Daniel Vetter , Jon Bloomfield , Chris Wilson , Joonas Lahtinen , =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= , Matthew Auld , Lionel Landwerlin , Dave Airlie , Jason Ekstrand References: <20210902142057.929669-1-daniel.vetter@ffwll.ch> <20210902142057.929669-7-daniel.vetter@ffwll.ch> <1cb4b910-ad02-ff02-46ef-7b3b4f393eb3@linux.intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: <68d369f3-b072-e138-8195-f6ff14f708a2@linux.intel.com> Date: Thu, 2 Sep 2021 17:41:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Intel-gfx] [PATCH 07/11] drm/i915: Add i915_gem_context_is_full_ppgtt 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 02/09/2021 16:22, Daniel Vetter wrote: > On Thu, Sep 02, 2021 at 03:54:36PM +0100, Tvrtko Ursulin wrote: >> On 02/09/2021 15:20, Daniel Vetter wrote: >>> And use it anywhere we have open-coded checks for ctx->vm that really >>> only check for full ppgtt. >>> >>> Plus for paranoia add a GEM_BUG_ON that checks it's really only set >>> when we have full ppgtt, just in case. gem_context->vm is different >>> since it's NULL in ggtt mode, unlike intel_context->vm or gt->vm, >>> which is always set. >>> >>> v2: 0day found a testcase that I missed. >>> >>> Reviewed-by: Maarten Lankhorst >>> Signed-off-by: Daniel Vetter >>> Cc: Jon Bloomfield >>> Cc: Chris Wilson >>> Cc: Maarten Lankhorst >>> Cc: Joonas Lahtinen >>> Cc: Daniel Vetter >>> Cc: "Thomas Hellström" >>> Cc: Matthew Auld >>> Cc: Lionel Landwerlin >>> Cc: Dave Airlie >>> Cc: Jason Ekstrand >>> --- >>> drivers/gpu/drm/i915/gem/i915_gem_context.c | 2 +- >>> drivers/gpu/drm/i915/gem/i915_gem_context.h | 7 +++++++ >>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +- >>> drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c | 6 +++--- >>> 4 files changed, 12 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c >>> index 7a566fb7cca4..1eec85944c1f 100644 >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c >>> @@ -1566,7 +1566,7 @@ static int get_ppgtt(struct drm_i915_file_private *file_priv, >>> int err; >>> u32 id; >>> - if (!rcu_access_pointer(ctx->vm)) >>> + if (!i915_gem_context_is_full_ppgtt(ctx)) >> >> It reads a bit wrong because GEM context cannot *be* full ppggt. It can be >> associated with a VM which is or isn't full ppgtt. So a test on a VM >> retrieved from a context is semnntically more correct. Perhaps you want to >> consider adding a helper to that effect instead? It could mean splitting >> into two helpers (getter + test) or maybe just renaming would work. Like >> i915_gem_context_has_full_ppgtt_vm(ctx)? > > The pointer isn't set when the driver/context isn't running in full ppgtt > mode. This is why I've added the GEM_BUG_ON to check we're not breaking > any invariants. So yeah it is a full ppgtt context or it's not, that is > indeed the question here. > > I'm happy to bikeshed the naming, but I don't see how your suggestion is > an improvement. I think the pointer being set or not is implementation detail, for instance we could have it always set just like it is in intel_context. I simply think GEM context *isn't* full ppgtt, but the VM is. And since GEM context *points* to a VM, *has* is the right verb in my mind. You did not write why do you not see has as more correct than is so I don't want to be guessing too much. Regards, Tvrtko >> >> Regards, >> >> Tvrtko >> >>> return -ENODEV; >>> rcu_read_lock(); >>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h >>> index da6e8b506d96..37536a260e6e 100644 >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.h >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h >>> @@ -154,6 +154,13 @@ i915_gem_context_vm(struct i915_gem_context *ctx) >>> return rcu_dereference_protected(ctx->vm, lockdep_is_held(&ctx->mutex)); >>> } >>> +static inline bool i915_gem_context_is_full_ppgtt(struct i915_gem_context *ctx) >>> +{ >>> + GEM_BUG_ON(!!rcu_access_pointer(ctx->vm) != HAS_FULL_PPGTT(ctx->i915)); >>> + >>> + return !!rcu_access_pointer(ctx->vm); >>> +} >>> + >>> static inline struct i915_address_space * >>> i915_gem_context_get_eb_vm(struct i915_gem_context *ctx) >>> { >>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c >>> index 905b1cbd22d5..40f08948f0b2 100644 >>> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c >>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c >>> @@ -749,7 +749,7 @@ static int eb_select_context(struct i915_execbuffer *eb) >>> return PTR_ERR(ctx); >>> eb->gem_context = ctx; >>> - if (rcu_access_pointer(ctx->vm)) >>> + if (i915_gem_context_is_full_ppgtt(ctx)) >>> eb->invalid_flags |= EXEC_OBJECT_NEEDS_GTT; >>> return 0; >>> diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c >>> index fc7fb33a3a52..947154e445a7 100644 >>> --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c >>> +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c >>> @@ -704,7 +704,7 @@ static int igt_ctx_exec(void *arg) >>> pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) [full-ppgtt? %s], err=%d\n", >>> ndwords, dw, max_dwords(obj), >>> engine->name, >>> - yesno(!!rcu_access_pointer(ctx->vm)), >>> + yesno(i915_gem_context_is_full_ppgtt(ctx)), >>> err); >>> intel_context_put(ce); >>> kernel_context_close(ctx); >>> @@ -838,7 +838,7 @@ static int igt_shared_ctx_exec(void *arg) >>> pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) [full-ppgtt? %s], err=%d\n", >>> ndwords, dw, max_dwords(obj), >>> engine->name, >>> - yesno(!!rcu_access_pointer(ctx->vm)), >>> + yesno(i915_gem_context_is_full_ppgtt(ctx)), >>> err); >>> intel_context_put(ce); >>> kernel_context_close(ctx); >>> @@ -1417,7 +1417,7 @@ static int igt_ctx_readonly(void *arg) >>> pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) [full-ppgtt? %s], err=%d\n", >>> ndwords, dw, max_dwords(obj), >>> ce->engine->name, >>> - yesno(!!ctx_vm(ctx)), >>> + yesno(i915_gem_context_is_full_ppgtt(ctx)), >>> err); >>> i915_gem_context_unlock_engines(ctx); >>> goto out_file; >>> >