From patchwork Tue Jun 8 09:28:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Hellstrom X-Patchwork-Id: 12306113 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 F2461C4743E for ; Tue, 8 Jun 2021 09:29:10 +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 C51A96124C for ; Tue, 8 Jun 2021 09:29:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C51A96124C 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=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 13EDA6EB61; Tue, 8 Jun 2021 09:29:06 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id A69826EB5F; Tue, 8 Jun 2021 09:29:03 +0000 (UTC) IronPort-SDR: f/LsqrneOAIkNDTXre8aq/zwTXPAkcmaWN8xVbcugHKd3wTlMfzNUTj//CafST94Xk1n0pXI30 SpeRlzhtIdFw== X-IronPort-AV: E=McAfee;i="6200,9189,10008"; a="226150949" X-IronPort-AV: E=Sophos;i="5.83,257,1616482800"; d="scan'208";a="226150949" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2021 02:29:03 -0700 IronPort-SDR: 3xpqC+8ivZPfIy1baRS4/OEeQKCwmebHkmaC72DLhsBSUwUYv2Ls95WOnGZBffmzGvGSxO3HGE f6Wkx8LZKd+w== X-IronPort-AV: E=Sophos;i="5.83,257,1616482800"; d="scan'208";a="551544350" Received: from mkayyal-mobl.ger.corp.intel.com (HELO thellst-mobl1.intel.com) ([10.249.254.115]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jun 2021 02:29:01 -0700 From: =?utf-8?q?Thomas_Hellstr=C3=B6m?= To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Date: Tue, 8 Jun 2021 11:28:38 +0200 Message-Id: <20210608092846.64198-2-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210608092846.64198-1-thomas.hellstrom@linux.intel.com> References: <20210608092846.64198-1-thomas.hellstrom@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 1/9] drm/i915: Reference objects on the ww object list 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: matthew.auld@intel.com, =?utf-8?q?Thomas_Hellstr=C3=B6m?= Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Since the ww transaction endpoint easily end up far out-of-scope of the objects on the ww object list, particularly for contending lock objects, make sure we reference objects on the list so they don't disappear under us. This comes with a performance penalty so it's been debated whether this is really needed. But I think this is motivated by the fact that locking is typically difficult to get right, and whatever we can do to make it simpler for developers moving forward should be done, unless the performance impact is far too high. Signed-off-by: Thomas Hellström Reviewed-by: Matthew Auld --- drivers/gpu/drm/i915/gem/i915_gem_object.h | 8 ++++++-- drivers/gpu/drm/i915/i915_gem.c | 4 ++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h index 7c0eb425cb3b..1fafcc89ecee 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h @@ -169,13 +169,17 @@ static inline int __i915_gem_object_lock(struct drm_i915_gem_object *obj, else ret = dma_resv_lock(obj->base.resv, ww ? &ww->ctx : NULL); - if (!ret && ww) + if (!ret && ww) { + i915_gem_object_get(obj); list_add_tail(&obj->obj_link, &ww->obj_list); + } if (ret == -EALREADY) ret = 0; - if (ret == -EDEADLK) + if (ret == -EDEADLK) { + i915_gem_object_get(obj); ww->contended = obj; + } return ret; } diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 589388dec48a..3f060ab58c5d 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1219,6 +1219,7 @@ static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww) while ((obj = list_first_entry_or_null(&ww->obj_list, struct drm_i915_gem_object, obj_link))) { list_del(&obj->obj_link); i915_gem_object_unlock(obj); + i915_gem_object_put(obj); } } @@ -1226,6 +1227,7 @@ void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj) { list_del(&obj->obj_link); i915_gem_object_unlock(obj); + i915_gem_object_put(obj); } void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww) @@ -1250,6 +1252,8 @@ int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww) if (!ret) list_add_tail(&ww->contended->obj_link, &ww->obj_list); + else + i915_gem_object_put(ww->contended); ww->contended = NULL;