From patchwork Mon Nov 23 11:34:26 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Harrison X-Patchwork-Id: 7679801 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 48ECA9F1BE for ; Mon, 23 Nov 2015 11:34:48 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2FC21206D7 for ; Mon, 23 Nov 2015 11:34:46 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id E9604206B6 for ; Mon, 23 Nov 2015 11:34:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6C59A721E9; Mon, 23 Nov 2015 03:34:44 -0800 (PST) X-Original-To: Intel-GFX@lists.freedesktop.org Delivered-To: Intel-GFX@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id 1A072721E7 for ; Mon, 23 Nov 2015 03:34:43 -0800 (PST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP; 23 Nov 2015 03:34:43 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,336,1444719600"; d="scan'208";a="937624" Received: from johnharr-linux.isw.intel.com ([10.102.226.93]) by fmsmga004.fm.intel.com with ESMTP; 23 Nov 2015 03:34:41 -0800 From: John.C.Harrison@Intel.com To: Intel-GFX@Lists.FreeDesktop.Org Date: Mon, 23 Nov 2015 11:34:26 +0000 Message-Id: <1448278471-31181-8-git-send-email-John.C.Harrison@Intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1448278471-31181-1-git-send-email-John.C.Harrison@Intel.com> References: <1448278471-31181-1-git-send-email-John.C.Harrison@Intel.com> Organization: Intel Corporation (UK) Ltd. - Co. Reg. #1134945 - Pipers Way, Swindon SN3 1RJ Subject: [Intel-gfx] [RFC 07/12] drm/i915: Delay the freeing of requests until retire time X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: John Harrison The request structure is reference counted. When the count reached zero, the request was immediately freed and all associated objects were unrefereced/unallocated. This meant that the driver mutex lock must be held at the point where the count reaches zero. This was fine while all references were held internally to the driver. However, the plan is to allow the underlying fence object (and hence the request itself) to be returned to other drivers and to userland. External users cannot be expected to acquire a driver private mutex lock. Rather than attempt to disentangle the request structure from the driver mutex lock, the decsion was to defer the free code until a later (safer) point. Hence this patch changes the unreference callback to merely move the request onto a delayed free list. The driver's retire worker thread will then process the list and actually call the free function on the requests. v2: New patch in series. v3: Updated after review comments by Tvrtko Ursulin. Rename list nodes to 'link' rather than 'list'. Update list processing to be more efficient/safer with respect to spinlocks. For: VIZ-5190 Signed-off-by: John Harrison Cc: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_drv.h | 22 +++---------------- drivers/gpu/drm/i915/i915_gem.c | 39 +++++++++++++++++++++++++++++---- drivers/gpu/drm/i915/intel_display.c | 2 +- drivers/gpu/drm/i915/intel_lrc.c | 2 ++ drivers/gpu/drm/i915/intel_pm.c | 2 +- drivers/gpu/drm/i915/intel_ringbuffer.c | 2 ++ drivers/gpu/drm/i915/intel_ringbuffer.h | 4 ++++ 7 files changed, 48 insertions(+), 25 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 7d6a7c0..fbf591f 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2185,14 +2185,9 @@ void i915_gem_track_fb(struct drm_i915_gem_object *old, * initial reference taken using kref_init */ struct drm_i915_gem_request { - /** - * Underlying object for implementing the signal/wait stuff. - * NB: Never return this fence object to user land! It is unsafe to - * let anything outside of the i915 driver get hold of the fence - * object as the clean up when decrementing the reference count - * requires holding the driver mutex lock. - */ + /** Underlying object for implementing the signal/wait stuff. */ struct fence fence; + struct list_head delayed_free_link; /** On Which ring this request was generated */ struct drm_i915_private *i915; @@ -2305,21 +2300,10 @@ i915_gem_request_reference(struct drm_i915_gem_request *req) static inline void i915_gem_request_unreference(struct drm_i915_gem_request *req) { - WARN_ON(!mutex_is_locked(&req->ring->dev->struct_mutex)); - fence_put(&req->fence); -} - -static inline void -i915_gem_request_unreference__unlocked(struct drm_i915_gem_request *req) -{ - struct drm_device *dev; - if (!req) return; - dev = req->ring->dev; - if (kref_put_mutex(&req->fence.refcount, fence_release, &dev->struct_mutex)) - mutex_unlock(&dev->struct_mutex); + fence_put(&req->fence); } static inline void i915_gem_request_assign(struct drm_i915_gem_request **pdst, diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 7a37fb7..171ae5f 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2617,10 +2617,27 @@ static void i915_set_reset_status(struct drm_i915_private *dev_priv, } } -static void i915_gem_request_free(struct fence *req_fence) +static void i915_gem_request_release(struct fence *req_fence) { struct drm_i915_gem_request *req = container_of(req_fence, typeof(*req), fence); + struct intel_engine_cs *ring = req->ring; + struct drm_i915_private *dev_priv = to_i915(ring->dev); + unsigned long flags; + + /* + * Need to add the request to a deferred dereference list to be + * processed at a mutex lock safe time. + */ + spin_lock_irqsave(&ring->delayed_free_lock, flags); + list_add_tail(&req->delayed_free_link, &ring->delayed_free_list); + spin_unlock_irqrestore(&ring->delayed_free_lock, flags); + + queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, 0); +} + +static void i915_gem_request_free(struct drm_i915_gem_request *req) +{ struct intel_context *ctx = req->ctx; WARN_ON(!mutex_is_locked(&req->ring->dev->struct_mutex)); @@ -2697,7 +2714,7 @@ static const struct fence_ops i915_gem_request_fops = { .enable_signaling = i915_gem_request_enable_signaling, .signaled = i915_gem_request_is_completed, .wait = fence_default_wait, - .release = i915_gem_request_free, + .release = i915_gem_request_release, .get_driver_name = i915_gem_request_get_driver_name, .get_timeline_name = i915_gem_request_get_timeline_name, .fence_value_str = i915_gem_request_fence_value_str, @@ -2951,6 +2968,10 @@ void i915_gem_reset(struct drm_device *dev) void i915_gem_retire_requests_ring(struct intel_engine_cs *ring) { + struct drm_i915_gem_request *req, *req_next; + LIST_HEAD(list_head); + unsigned long flags; + WARN_ON(i915_verify_lists(ring->dev)); /* Retire requests first as we use it above for the early return. @@ -2994,6 +3015,15 @@ i915_gem_retire_requests_ring(struct intel_engine_cs *ring) i915_gem_request_assign(&ring->trace_irq_req, NULL); } + /* Really free any requests that were recently unreferenced */ + spin_lock_irqsave(&ring->delayed_free_lock, flags); + list_splice_init(&ring->delayed_free_list, &list_head); + spin_unlock_irqrestore(&ring->delayed_free_lock, flags); + list_for_each_entry_safe(req, req_next, &list_head, delayed_free_link) { + list_del(&req->delayed_free_link); + i915_gem_request_free(req); + } + WARN_ON(i915_verify_lists(ring->dev)); } @@ -3184,7 +3214,7 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file) ret = __i915_wait_request(req[i], reset_counter, true, args->timeout_ns > 0 ? &args->timeout_ns : NULL, file->driver_priv); - i915_gem_request_unreference__unlocked(req[i]); + i915_gem_request_unreference(req[i]); } return ret; @@ -4179,7 +4209,7 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file) if (ret == 0) queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, 0); - i915_gem_request_unreference__unlocked(target); + i915_gem_request_unreference(target); return ret; } @@ -5036,6 +5066,7 @@ init_ring_lists(struct intel_engine_cs *ring) { INIT_LIST_HEAD(&ring->active_list); INIT_LIST_HEAD(&ring->request_list); + INIT_LIST_HEAD(&ring->delayed_free_list); } void diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 510365e..9291a1d 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -11256,7 +11256,7 @@ static void intel_mmio_flip_work_func(struct work_struct *work) mmio_flip->crtc->reset_counter, false, NULL, &mmio_flip->i915->rps.mmioflips)); - i915_gem_request_unreference__unlocked(mmio_flip->req); + i915_gem_request_unreference(mmio_flip->req); } intel_do_mmio_flip(mmio_flip); diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 2b56651..06a398a 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1920,7 +1920,9 @@ static int logical_ring_init(struct drm_device *dev, struct intel_engine_cs *rin ring->dev = dev; INIT_LIST_HEAD(&ring->active_list); INIT_LIST_HEAD(&ring->request_list); + INIT_LIST_HEAD(&ring->delayed_free_list); spin_lock_init(&ring->fence_lock); + spin_lock_init(&ring->delayed_free_lock); i915_gem_batch_pool_init(dev, &ring->batch_pool); init_waitqueue_head(&ring->irq_queue); diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index c207a3a..e2d34a6 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -7174,7 +7174,7 @@ static void __intel_rps_boost_work(struct work_struct *work) gen6_rps_boost(to_i915(req->ring->dev), NULL, req->emitted_jiffies); - i915_gem_request_unreference__unlocked(req); + i915_gem_request_unreference(req); kfree(boost); } diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index f4a6403..e5573e7 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -2158,7 +2158,9 @@ static int intel_init_ring_buffer(struct drm_device *dev, INIT_LIST_HEAD(&ring->request_list); INIT_LIST_HEAD(&ring->execlist_queue); INIT_LIST_HEAD(&ring->buffers); + INIT_LIST_HEAD(&ring->delayed_free_list); spin_lock_init(&ring->fence_lock); + spin_lock_init(&ring->delayed_free_lock); i915_gem_batch_pool_init(dev, &ring->batch_pool); memset(ring->semaphore.sync_seqno, 0, sizeof(ring->semaphore.sync_seqno)); diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 356b6a8..77384ed 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -301,6 +301,10 @@ struct intel_engine_cs { */ u32 last_submitted_seqno; + /* deferred free list to allow unreferencing requests outside the driver */ + struct list_head delayed_free_list; + spinlock_t delayed_free_lock; + bool gpu_caches_dirty; wait_queue_head_t irq_queue;