From patchwork Tue Jul 28 15:30:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11689419 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E7B59138C for ; Tue, 28 Jul 2020 15:31:08 +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 D0B34206D4 for ; Tue, 28 Jul 2020 15:31:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D0B34206D4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk 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 854EB6E378; Tue, 28 Jul 2020 15:31:05 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id DDEC86E375 for ; Tue, 28 Jul 2020 15:31:03 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from build.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 21959610-1500050 for multiple; Tue, 28 Jul 2020 16:30:49 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 28 Jul 2020 16:30:47 +0100 Message-Id: <20200728153049.27682-5-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200728153049.27682-1-chris@chris-wilson.co.uk> References: <20200728153049.27682-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 5/7] drm/i915: Make the stale cached active node available for any timeline 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: thomas.hellstrom@intel.com, Chris Wilson Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Rather than require the next timeline after idling to match the MRU before idling, reset the index on the node and allow it to match the first request. However, this requires cmpxchg(u64) and so is not trivial on 32b, so for compatibility we just fallback to keeping the cached node pointing to the MRU timeline. Signed-off-by: Chris Wilson Reviewed-by: Thomas Hellström --- drivers/gpu/drm/i915/i915_active.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index b9bd5578ff54..03b246cb8466 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -157,6 +157,10 @@ __active_retire(struct i915_active *ref) rb_link_node(&ref->cache->node, NULL, &ref->tree.rb_node); rb_insert_color(&ref->cache->node, &ref->tree); GEM_BUG_ON(ref->tree.rb_node != &ref->cache->node); + + /* Make the cached node available for reuse with any timeline */ + if (IS_ENABLED(CONFIG_64BIT)) + ref->cache->timeline = 0; /* needs cmpxchg(u64) */ } spin_unlock_irqrestore(&ref->tree_lock, flags); @@ -235,6 +239,8 @@ static struct active_node *__active_lookup(struct i915_active *ref, u64 idx) { struct active_node *it; + GEM_BUG_ON(idx == 0); /* 0 is the unordered timeline, rsvd for cache */ + /* * We track the most recently used timeline to skip a rbtree search * for the common case, under typical loads we never need the rbtree @@ -243,8 +249,17 @@ static struct active_node *__active_lookup(struct i915_active *ref, u64 idx) * current timeline. */ it = READ_ONCE(ref->cache); - if (it && it->timeline == idx) - return it; + if (it) { + u64 cached = READ_ONCE(it->timeline); + + if (cached == idx) + return it; + +#ifdef CONFIG_64BIT /* for cmpxchg(u64) */ + if (!cached && !cmpxchg(&it->timeline, 0, idx)) + return it; +#endif + } BUILD_BUG_ON(offsetof(typeof(*it), node));