From patchwork Tue Jun 15 13:14:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Hellstrom X-Patchwork-Id: 12321325 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,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 B5B48C49361 for ; Tue, 15 Jun 2021 13:15:11 +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 66D8D6109D for ; Tue, 15 Jun 2021 13:15:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 66D8D6109D 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 0C03F6E2C7; Tue, 15 Jun 2021 13:15:09 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id E242E89FF7 for ; Tue, 15 Jun 2021 13:15:06 +0000 (UTC) IronPort-SDR: zs7NsfWXklWo9hkmPYlIEYGU6TXDL+fCktHy/klyrzAWw/vkurTo9zj4xDqhiGsx16YwyruNr+ vOpkwadaqT5w== X-IronPort-AV: E=McAfee;i="6200,9189,10015"; a="205804346" X-IronPort-AV: E=Sophos;i="5.83,275,1616482800"; d="scan'208";a="205804346" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2021 06:15:06 -0700 IronPort-SDR: X1i8ayIE5tXNZngKL1Jy+0mTa0DrEq7OkVX6h8ZL+VrPv386bHx4PHaQZwyG5MTOBAjZowpqVL IK1plwuAHAng== X-IronPort-AV: E=Sophos;i="5.83,275,1616482800"; d="scan'208";a="554443304" Received: from vgribano-mobl.ccr.corp.intel.com (HELO thellst-mobl1.intel.com) ([10.249.254.53]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2021 06:15:05 -0700 From: =?utf-8?q?Thomas_Hellstr=C3=B6m?= To: intel-gfx@lists.freedesktop.org Date: Tue, 15 Jun 2021 15:14:40 +0200 Message-Id: <20210615131451.61023-2-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210615131451.61023-1-thomas.hellstrom@linux.intel.com> References: <20210615131451.61023-1-thomas.hellstrom@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v4 01/12] 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: =?utf-8?q?Thomas_Hellstr=C3=B6m?= , matthew.auld@intel.com 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 d66aa00d023a..241666931945 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 6a0a3f0e36e1..c62dcd0e341a 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1222,6 +1222,7 @@ 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); } } @@ -1229,6 +1230,7 @@ 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) @@ -1253,6 +1255,8 @@ 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;