From patchwork Fri Jul 31 08:50:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11694461 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 D815F913 for ; Fri, 31 Jul 2020 08:50:26 +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 C06A920829 for ; Fri, 31 Jul 2020 08:50:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C06A920829 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 235C86EA25; Fri, 31 Jul 2020 08:50:26 +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 599E36EA1E for ; Fri, 31 Jul 2020 08:50:20 +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 21990228-1500050 for ; Fri, 31 Jul 2020 09:50:16 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Fri, 31 Jul 2020 09:50:12 +0100 Message-Id: <20200731085015.32368-4-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200731085015.32368-1-chris@chris-wilson.co.uk> References: <20200731085015.32368-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [CI 4/7] drm/i915: Keep the most recently used active-fence upon discard 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" Whenever an i915_active idles, we prune its tree of old fence slots to prevent a gradual leak should it be used to track many, many timelines. The downside is that we then have to frequently reallocate the rbtree. A compromise is that we keep the most recently used fence slot, and reuse that for the next active reference as that is the most likely timeline to be reused. Signed-off-by: Chris Wilson Reviewed-by: Thomas Hellström --- drivers/gpu/drm/i915/i915_active.c | 27 ++++++++++++++++++++------- drivers/gpu/drm/i915/i915_active.h | 4 ---- 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index 3a728401c09c..b9bd5578ff54 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -130,8 +130,8 @@ static inline void debug_active_assert(struct i915_active *ref) { } static void __active_retire(struct i915_active *ref) { + struct rb_root root = RB_ROOT; struct active_node *it, *n; - struct rb_root root; unsigned long flags; GEM_BUG_ON(i915_active_is_idle(ref)); @@ -143,9 +143,21 @@ __active_retire(struct i915_active *ref) GEM_BUG_ON(rcu_access_pointer(ref->excl.fence)); debug_active_deactivate(ref); - root = ref->tree; - ref->tree = RB_ROOT; - ref->cache = NULL; + /* Even if we have not used the cache, we may still have a barrier */ + if (!ref->cache) + ref->cache = fetch_node(ref->tree.rb_node); + + /* Keep the MRU cached node for reuse */ + if (ref->cache) { + /* Discard all other nodes in the tree */ + rb_erase(&ref->cache->node, &ref->tree); + root = ref->tree; + + /* Rebuild the tree with only the cached node */ + 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); + } spin_unlock_irqrestore(&ref->tree_lock, flags); @@ -156,6 +168,7 @@ __active_retire(struct i915_active *ref) /* ... except if you wait on it, you must manage your own references! */ wake_up_var(ref); + /* Finally free the discarded timeline tree */ rbtree_postorder_for_each_entry_safe(it, n, &root, node) { GEM_BUG_ON(i915_active_fence_isset(&it->base)); kmem_cache_free(global.slab_cache, it); @@ -745,16 +758,16 @@ int i915_sw_fence_await_active(struct i915_sw_fence *fence, return await_active(ref, flags, sw_await_fence, fence, fence); } -#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) void i915_active_fini(struct i915_active *ref) { debug_active_fini(ref); GEM_BUG_ON(atomic_read(&ref->count)); GEM_BUG_ON(work_pending(&ref->work)); - GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree)); mutex_destroy(&ref->mutex); + + if (ref->cache) + kmem_cache_free(global.slab_cache, ref->cache); } -#endif static inline bool is_idle_barrier(struct active_node *node, u64 idx) { diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h index 73ded3c52a04..b9e0394e2975 100644 --- a/drivers/gpu/drm/i915/i915_active.h +++ b/drivers/gpu/drm/i915/i915_active.h @@ -217,11 +217,7 @@ i915_active_is_idle(const struct i915_active *ref) return !atomic_read(&ref->count); } -#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) void i915_active_fini(struct i915_active *ref); -#else -static inline void i915_active_fini(struct i915_active *ref) { } -#endif int i915_active_acquire_preallocate_barrier(struct i915_active *ref, struct intel_engine_cs *engine);