From patchwork Tue Mar 24 12:07:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11455239 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 08A9D15AB for ; Tue, 24 Mar 2020 12:07:45 +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 DC00C20870 for ; Tue, 24 Mar 2020 12:07:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC00C20870 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 37B616E270; Tue, 24 Mar 2020 12:07:44 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5D56C6E270 for ; Tue, 24 Mar 2020 12:07:42 +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 20673276-1500050 for multiple; Tue, 24 Mar 2020 12:07:18 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 24 Mar 2020 12:07:18 +0000 Message-Id: <20200324120718.977-2-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200324120718.977-1-chris@chris-wilson.co.uk> References: <20200324120718.977-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 2/2] drm/i915: Immediately execute the fenced work 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" If the caller allows and we do not have to wait for any signals, immediately execute the work within the caller's process. By doing so we avoid the overhead of scheduling a new task, and the latency in executing it, at the cost of pulling that work back into the immediate context. (Sometimes we still prefer to offload the task to another cpu, especially if we plan on executing many such tasks in parallel for this client.) Signed-off-by: Chris Wilson --- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +- drivers/gpu/drm/i915/i915_sw_fence_work.c | 5 +++- drivers/gpu/drm/i915/i915_sw_fence_work.h | 23 +++++++++++++++++++ drivers/gpu/drm/i915/i915_vma.c | 2 +- 4 files changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 1e06f5e36bbd..32e27831f423 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -1823,7 +1823,7 @@ static int eb_parse_pipeline(struct i915_execbuffer *eb, dma_resv_add_excl_fence(shadow->resv, &pw->base.dma); dma_resv_unlock(shadow->resv); - dma_fence_work_commit(&pw->base); + dma_fence_work_commit_imm(&pw->base); return 0; err_batch_unlock: diff --git a/drivers/gpu/drm/i915/i915_sw_fence_work.c b/drivers/gpu/drm/i915/i915_sw_fence_work.c index 997b2998f1f2..a3a81bb8f2c3 100644 --- a/drivers/gpu/drm/i915/i915_sw_fence_work.c +++ b/drivers/gpu/drm/i915/i915_sw_fence_work.c @@ -38,7 +38,10 @@ fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state) if (!f->dma.error) { dma_fence_get(&f->dma); - queue_work(system_unbound_wq, &f->work); + if (test_bit(DMA_FENCE_WORK_IMM, &f->dma.flags)) + fence_work(&f->work); + else + queue_work(system_unbound_wq, &f->work); } else { fence_complete(f); } diff --git a/drivers/gpu/drm/i915/i915_sw_fence_work.h b/drivers/gpu/drm/i915/i915_sw_fence_work.h index 3a22b287e201..2c409f11c5c5 100644 --- a/drivers/gpu/drm/i915/i915_sw_fence_work.h +++ b/drivers/gpu/drm/i915/i915_sw_fence_work.h @@ -32,6 +32,10 @@ struct dma_fence_work { const struct dma_fence_work_ops *ops; }; +enum { + DMA_FENCE_WORK_IMM = DMA_FENCE_FLAG_USER_BITS, +}; + void dma_fence_work_init(struct dma_fence_work *f, const struct dma_fence_work_ops *ops); int dma_fence_work_chain(struct dma_fence_work *f, struct dma_fence *signal); @@ -41,4 +45,23 @@ static inline void dma_fence_work_commit(struct dma_fence_work *f) i915_sw_fence_commit(&f->chain); } +/** + * dma_fence_work_commit_imm: Commit the fence, and if possible execute locally. + * @f: the fenced worker + * + * Instead of always scheduling a worker to execute the callback (see + * dma_fence_work_commit()), we try to execute the callback immediately in + * the local context. It is required that the fence be committed before it + * is published, and that no other threads try to tamper with the number + * of asynchronous waits on the fence (or else the callback will be + * executed in the wrong context, i.e. not the callers). + */ +static inline void dma_fence_work_commit_imm(struct dma_fence_work *f) +{ + if (atomic_read(&f->chain.pending) <= 1) + __set_bit(DMA_FENCE_WORK_IMM, &f->dma.flags); + + dma_fence_work_commit(f); +} + #endif /* I915_SW_FENCE_WORK_H */ diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 08699fa069aa..191577a98390 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -980,7 +980,7 @@ int i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags) mutex_unlock(&vma->vm->mutex); err_fence: if (work) - dma_fence_work_commit(&work->base); + dma_fence_work_commit_imm(&work->base); if (wakeref) intel_runtime_pm_put(&vma->vm->i915->runtime_pm, wakeref); err_pages: