From patchwork Tue May 26 21:06:33 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robert Jarzmik X-Patchwork-Id: 6486011 Return-Path: X-Original-To: patchwork-dmaengine@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 129449F40A for ; Tue, 26 May 2015 21:08:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F13FE203FB for ; Tue, 26 May 2015 21:08:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFE15206D0 for ; Tue, 26 May 2015 21:08:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751876AbbEZVIH (ORCPT ); Tue, 26 May 2015 17:08:07 -0400 Received: from smtp01.smtpout.orange.fr ([80.12.242.123]:47423 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751412AbbEZVIE (ORCPT ); Tue, 26 May 2015 17:08:04 -0400 Received: from belgarion.home ([109.222.71.104]) by mwinf5d02 with ME id Yl7z1q0032EzjTh03l819K; Tue, 26 May 2015 23:08:02 +0200 X-ME-Helo: belgarion.home X-ME-Date: Tue, 26 May 2015 23:08:02 +0200 X-ME-IP: 109.222.71.104 From: Robert Jarzmik To: Vinod Koul , Jonathan Corbet Cc: dmaengine@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Robert Jarzmik , Lars-Peter Clausen , Maxime Ripard Subject: [PATCH RESEND 1/2] dmaengine: virt-dma: don't always free descriptor upon completion Date: Tue, 26 May 2015 23:06:33 +0200 Message-Id: <1432674394-32007-2-git-send-email-robert.jarzmik@free.fr> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1432674394-32007-1-git-send-email-robert.jarzmik@free.fr> References: <1432674394-32007-1-git-send-email-robert.jarzmik@free.fr> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM, RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=ham 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 This patch attempts to enhance the case of a transfer submitted multiple times, and where the cost of creating the descriptors chain is not negligible. This happens with big video buffers (several megabytes, ie. several thousands of linked descriptors in one scatter-gather list). In these cases, a video driver would want to do : - tx = dmaengine_prep_slave_sg() - dma_engine_submit(tx); - dma_async_issue_pending() - wait for video completion - read video data (or not, skipping a frame is also possible) - dma_engine_submit(tx) => here, the descriptors chain recalculation will take time => the dma coherent allocation over and over might create holes in the dma pool, which is counter-productive. - dma_async_issue_pending() - etc ... In order to cope with this case, virt-dma is modified to prevent freeing the descriptors upon completion if DMA_CTRL_ACK flag is set in the transfer. Signed-off-by: Robert Jarzmik Cc: Lars-Peter Clausen Cc: Maxime Ripard --- drivers/dma/virt-dma.c | 19 +++++++++++++------ drivers/dma/virt-dma.h | 13 ++++++++++++- 2 files changed, 25 insertions(+), 7 deletions(-) diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c index 6f80432..7d2c17d 100644 --- a/drivers/dma/virt-dma.c +++ b/drivers/dma/virt-dma.c @@ -29,7 +29,7 @@ dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx) spin_lock_irqsave(&vc->lock, flags); cookie = dma_cookie_assign(tx); - list_add_tail(&vd->node, &vc->desc_submitted); + list_move_tail(&vd->node, &vc->desc_submitted); spin_unlock_irqrestore(&vc->lock, flags); dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n", @@ -83,8 +83,10 @@ static void vchan_complete(unsigned long arg) cb_data = vd->tx.callback_param; list_del(&vd->node); - - vc->desc_free(vd); + if (async_tx_test_ack(&vd->tx)) + list_add(&vd->node, &vc->desc_allocated); + else + vc->desc_free(vd); if (cb) cb(cb_data); @@ -96,9 +98,13 @@ void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head) while (!list_empty(head)) { struct virt_dma_desc *vd = list_first_entry(head, struct virt_dma_desc, node); - list_del(&vd->node); - dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd); - vc->desc_free(vd); + if (async_tx_test_ack(&vd->tx)) { + list_move_tail(&vd->node, &vc->desc_allocated); + } else { + dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd); + list_del(&vd->node); + vc->desc_free(vd); + } } } EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list); @@ -108,6 +114,7 @@ void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev) dma_cookie_init(&vc->chan); spin_lock_init(&vc->lock); + INIT_LIST_HEAD(&vc->desc_allocated); INIT_LIST_HEAD(&vc->desc_submitted); INIT_LIST_HEAD(&vc->desc_issued); INIT_LIST_HEAD(&vc->desc_completed); diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h index 181b952..189e75d 100644 --- a/drivers/dma/virt-dma.h +++ b/drivers/dma/virt-dma.h @@ -29,6 +29,7 @@ struct virt_dma_chan { spinlock_t lock; /* protected by vc.lock */ + struct list_head desc_allocated; struct list_head desc_submitted; struct list_head desc_issued; struct list_head desc_completed; @@ -55,11 +56,16 @@ static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan struct virt_dma_desc *vd, unsigned long tx_flags) { extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); + unsigned long flags; dma_async_tx_descriptor_init(&vd->tx, &vc->chan); vd->tx.flags = tx_flags; vd->tx.tx_submit = vchan_tx_submit; + spin_lock_irqsave(&vc->lock, flags); + list_add_tail(&vd->node, &vc->desc_allocated); + spin_unlock_irqrestore(&vc->lock, flags); + return &vd->tx; } @@ -122,7 +128,8 @@ static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) } /** - * vchan_get_all_descriptors - obtain all submitted and issued descriptors + * vchan_get_all_descriptors - obtain all allocated, submitted and issued + * descriptors * vc: virtual channel to get descriptors from * head: list of descriptors found * @@ -134,6 +141,7 @@ static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, struct list_head *head) { + list_splice_tail_init(&vc->desc_allocated, head); list_splice_tail_init(&vc->desc_submitted, head); list_splice_tail_init(&vc->desc_issued, head); list_splice_tail_init(&vc->desc_completed, head); @@ -141,11 +149,14 @@ static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) { + struct virt_dma_desc *vd; unsigned long flags; LIST_HEAD(head); spin_lock_irqsave(&vc->lock, flags); vchan_get_all_descriptors(vc, &head); + list_for_each_entry(vd, &head, node) + async_tx_clear_ack(&vd->tx); spin_unlock_irqrestore(&vc->lock, flags); vchan_dma_desc_free_list(vc, &head);