From patchwork Tue Jan 5 15:35:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Maarten Lankhorst X-Patchwork-Id: 11999545 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 34092C433E0 for ; Tue, 5 Jan 2021 15:46:13 +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 F148C22BF3 for ; Tue, 5 Jan 2021 15:46:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F148C22BF3 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 2186F6E182; Tue, 5 Jan 2021 15:45:48 +0000 (UTC) Received: from mblankhorst.nl (mblankhorst.nl [141.105.120.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id EEA2B6E153 for ; Tue, 5 Jan 2021 15:45:40 +0000 (UTC) From: Maarten Lankhorst To: intel-gfx@lists.freedesktop.org Date: Tue, 5 Jan 2021 16:35:56 +0100 Message-Id: <20210105153558.134272-63-maarten.lankhorst@linux.intel.com> X-Mailer: git-send-email 2.30.0.rc1 In-Reply-To: <20210105153558.134272-1-maarten.lankhorst@linux.intel.com> References: <20210105153558.134272-1-maarten.lankhorst@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v6 62/64] drm/i915: Keep userpointer bindings if seqcount is unchanged, v2. 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: Dan Carpenter Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Instead of force unbinding and rebinding every time, we try to check if our notifier seqcount is still correct when pages are bound. This way we only rebind userptr when we need to, and prevent stalls. Changes since v1: - Missing mutex_unlock, reported by kbuild. Reported-by: kernel test robot Reported-by: Dan Carpenter Signed-off-by: Maarten Lankhorst Reviewed-by: Thomas Hellström --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 27 ++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index 84c3e8dc1491..44fc0df89784 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -274,12 +274,33 @@ int i915_gem_object_userptr_submit_init(struct drm_i915_gem_object *obj) if (ret) return ret; - /* Make sure userptr is unbound for next attempt, so we don't use stale pages. */ - ret = i915_gem_object_userptr_unbind(obj, false); + /* optimistically try to preserve current pages while unlocked */ + if (i915_gem_object_has_pages(obj) && + !mmu_interval_check_retry(&obj->userptr.notifier, + obj->userptr.notifier_seq)) { + spin_lock(&i915->mm.notifier_lock); + if (obj->userptr.pvec && + !mmu_interval_read_retry(&obj->userptr.notifier, + obj->userptr.notifier_seq)) { + obj->userptr.page_ref++; + + /* We can keep using the current binding, this is the fastpath */ + ret = 1; + } + spin_unlock(&i915->mm.notifier_lock); + } + + if (!ret) { + /* Make sure userptr is unbound for next attempt, so we don't use stale pages. */ + ret = i915_gem_object_userptr_unbind(obj, false); + } i915_gem_object_unlock(obj); - if (ret) + if (ret < 0) return ret; + if (ret > 0) + return 0; + notifier_seq = mmu_interval_read_begin(&obj->userptr.notifier); pvec = kvmalloc_array(num_pages, sizeof(struct page *), GFP_KERNEL);