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[23.128.96.18]) by mx.google.com with ESMTP id n11si2920538ejg.99.2021.03.11.17.45.29; Thu, 11 Mar 2021 17:45:51 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass (test mode) header.i=@ideasonboard.com header.s=mail header.b=U2VNk63w; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230433AbhCLBn4 (ORCPT + 99 others); Thu, 11 Mar 2021 20:43:56 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:33876 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229960AbhCLBnv (ORCPT ); Thu, 11 Mar 2021 20:43:51 -0500 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 7E1C688F; Fri, 12 Mar 2021 02:43:49 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1615513429; bh=1gieA2urQuS/+9QDXJpKW+VD4ZXjYbg3KRNmYZfMqfs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U2VNk63wD4+ugP6O6dAN6dvpM/ZDBkSFt5w2y9qghGvOy1q0aqbrbxHTt2Mu+KQFv abeMKwfyhlGogHbhp8h/ywTbSN3rFt8V8Gq9fLaYPvmh/n7pMUnDrXh1m1Zuf74nCK AcVpk6tbphNVwRmF9ldLLaY/ILnLtvuwNLsCCs5k= Date: Fri, 12 Mar 2021 03:43:15 +0200 From: Laurent Pinchart To: Christoph Hellwig Cc: Mauro Carvalho Chehab , Marek Szyprowski , Tomasz Figa , Ricardo Ribalda , Sergey Senozhatsky , iommu@lists.linux-foundation.org, Robin Murphy , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Subject: Re: [PATCH 6/6] media: uvcvideo: Use dma_alloc_noncontiguos API Message-ID: References: <20210301085236.947011-1-hch@lst.de> <20210301085236.947011-7-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org And I forgot to mention: On Fri, Mar 12, 2021 at 03:42:14AM +0200, Laurent Pinchart wrote: > Hi Christoph and Ricardo, > > Thank you for the patch. > > On Mon, Mar 01, 2021 at 09:52:36AM +0100, Christoph Hellwig wrote: > > From: Ricardo Ribalda > > > > On architectures where the is no coherent caching such as ARM use the > > s/the is/there is/ > > > dma_alloc_noncontiguos API and handle manually the cache flushing using > > s/dma_alloc_noncontiguos/dma_alloc_noncontiguous/ > > (and in the subject line too) > > > dma_sync_sgtable(). > > > > With this patch on the affected architectures we can measure up to 20x > > performance improvement in uvc_video_copy_data_work(). Wow, great work ! :-) > > > > Eg: aarch64 with an external usb camera > > > > NON_CONTIGUOUS > > frames: 999 > > packets: 999 > > empty: 0 (0 %) > > errors: 0 > > invalid: 0 > > pts: 0 early, 0 initial, 999 ok > > scr: 0 count ok, 0 diff ok > > sof: 2048 <= sof <= 0, freq 0.000 kHz > > bytes 67034480 : duration 33303 > > FPS: 29.99 > > URB: 523446/4993 uS/qty: 104.836 avg 132.532 std 13.230 min 831.094 max (uS) > > header: 76564/4993 uS/qty: 15.334 avg 15.229 std 3.438 min 186.875 max (uS) > > latency: 468945/4992 uS/qty: 93.939 avg 132.577 std 9.531 min 824.010 max (uS) > > decode: 54161/4993 uS/qty: 10.847 avg 6.313 std 1.614 min 111.458 max (uS) > > raw decode speed: 9.931 Gbits/s > > raw URB handling speed: 1.025 Gbits/s > > throughput: 16.102 Mbits/s > > URB decode CPU usage 0.162600 % > > > > COHERENT > > frames: 999 > > packets: 999 > > empty: 0 (0 %) > > errors: 0 > > invalid: 0 > > pts: 0 early, 0 initial, 999 ok > > scr: 0 count ok, 0 diff ok > > sof: 2048 <= sof <= 0, freq 0.000 kHz > > bytes 54683536 : duration 33302 > > FPS: 29.99 > > URB: 1478135/4000 uS/qty: 369.533 avg 390.357 std 22.968 min 3337.865 max (uS) > > header: 79761/4000 uS/qty: 19.940 avg 18.495 std 1.875 min 336.719 max (uS) > > latency: 281077/4000 uS/qty: 70.269 avg 83.102 std 5.104 min 735.000 max (uS) > > decode: 1197057/4000 uS/qty: 299.264 avg 318.080 std 1.615 min 2806.667 max (uS) > > raw decode speed: 365.470 Mbits/s > > raw URB handling speed: 295.986 Mbits/s > > throughput: 13.136 Mbits/s > > URB decode CPU usage 3.594500 % > > > > Signed-off-by: Ricardo Ribalda > > Reviewed-by: Tomasz Figa > > Signed-off-by: Christoph Hellwig > > --- > > drivers/media/usb/uvc/uvc_video.c | 79 ++++++++++++++++++++++--------- > > drivers/media/usb/uvc/uvcvideo.h | 4 +- > > 2 files changed, 60 insertions(+), 23 deletions(-) > > > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c > > index f2f565281e63ff..d008c68fb6c806 100644 > > --- a/drivers/media/usb/uvc/uvc_video.c > > +++ b/drivers/media/usb/uvc/uvc_video.c > > @@ -6,11 +6,13 @@ > > * Laurent Pinchart (laurent.pinchart@ideasonboard.com) > > */ > > > > Should we include ? > > > +#include > > #include > > #include > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -1096,6 +1098,26 @@ static int uvc_video_decode_start(struct uvc_streaming *stream, > > return data[0]; > > } > > > > +static inline struct device *stream_to_dmadev(struct uvc_streaming *stream) > > +{ > > + return bus_to_hcd(stream->dev->udev->bus)->self.sysdev; > > +} > > + > > +static void uvc_urb_dma_sync(struct uvc_urb *uvc_urb, bool for_device) > > +{ > > + struct device *dma_dev = stream_to_dmadev(uvc_urb->stream); > > + > > + if (for_device) { > > + dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt, > > + DMA_FROM_DEVICE); > > The uvcvideo driver also supports video output devices (they are fairly > rare, but they exist). We thus need to handle DMA_TO_DEVICE too. > > > + } else { > > + dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt, > > + DMA_FROM_DEVICE); > > + invalidate_kernel_vmap_range(uvc_urb->buffer, > > + uvc_urb->stream->urb_size); > > + } > > +} > > + > > /* > > * uvc_video_decode_data_work: Asynchronous memcpy processing > > * > > @@ -1117,6 +1139,8 @@ static void uvc_video_copy_data_work(struct work_struct *work) > > uvc_queue_buffer_release(op->buf); > > } > > > > + uvc_urb_dma_sync(uvc_urb, true); > > + > > ret = usb_submit_urb(uvc_urb->urb, GFP_KERNEL); > > if (ret < 0) > > dev_err(&uvc_urb->stream->intf->dev, > > @@ -1541,10 +1565,12 @@ static void uvc_video_complete(struct urb *urb) > > * Process the URB headers, and optionally queue expensive memcpy tasks > > * to be deferred to a work queue. > > */ > > + uvc_urb_dma_sync(uvc_urb, false); > > stream->decode(uvc_urb, buf, buf_meta); > > > > /* If no async work is needed, resubmit the URB immediately. */ > > if (!uvc_urb->async_operations) { > > + uvc_urb_dma_sync(uvc_urb, true); > > ret = usb_submit_urb(uvc_urb->urb, GFP_ATOMIC); > > if (ret < 0) > > dev_err(&stream->intf->dev, > > @@ -1560,24 +1586,46 @@ static void uvc_video_complete(struct urb *urb) > > */ > > static void uvc_free_urb_buffers(struct uvc_streaming *stream) > > { > > + struct device *dma_dev = stream_to_dmadev(stream); > > struct uvc_urb *uvc_urb; > > > > for_each_uvc_urb(uvc_urb, stream) { > > if (!uvc_urb->buffer) > > continue; > > > > -#ifndef CONFIG_DMA_NONCOHERENT > > - usb_free_coherent(stream->dev->udev, stream->urb_size, > > - uvc_urb->buffer, uvc_urb->dma); > > -#else > > - kfree(uvc_urb->buffer); > > -#endif > > + dma_vunmap_noncontiguous(dma_dev, uvc_urb->buffer); > > + dma_free_noncontiguous(dma_dev, stream->urb_size, uvc_urb->sgt, > > + DMA_FROM_DEVICE); > > + > > uvc_urb->buffer = NULL; > > Maybe also > > uvc_urb->sgt = NULL; > > ? It's not strictly mandatory, but may make use-after-free bugs easier > to spot. > > > } > > > > stream->urb_size = 0; > > } > > > > +static bool uvc_alloc_urb_buffer(struct uvc_streaming *stream, > > + struct uvc_urb *uvc_urb, gfp_t gfp_flags) > > +{ > > + struct device *dma_dev = stream_to_dmadev(stream); > > + > > + > > Extra blank line. > > > + uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size, > > + DMA_FROM_DEVICE, gfp_flags, 0); > > + if (!uvc_urb->sgt) > > + return false; > > + uvc_urb->dma = uvc_urb->sgt->sgl->dma_address; > > + > > + uvc_urb->buffer = dma_vmap_noncontiguous(dma_dev, stream->urb_size, > > + uvc_urb->sgt); > > + if (!uvc_urb->buffer) { > > + dma_free_noncontiguous(dma_dev, stream->urb_size, > > + uvc_urb->sgt, DMA_FROM_DEVICE); > > Same here, > > uvc_urb->sgt = NULL; > > > + return false; > > + } > > + > > + return true; > > +} > > + > > /* > > * Allocate transfer buffers. This function can be called with buffers > > * already allocated when resuming from suspend, in which case it will > > @@ -1608,19 +1656,11 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream, > > > > /* Retry allocations until one succeed. */ > > for (; npackets > 1; npackets /= 2) { > > + stream->urb_size = psize * npackets; > > A blank line here would be nice. > > > for (i = 0; i < UVC_URBS; ++i) { > > struct uvc_urb *uvc_urb = &stream->uvc_urb[i]; > > > > - stream->urb_size = psize * npackets; > > -#ifndef CONFIG_DMA_NONCOHERENT > > - uvc_urb->buffer = usb_alloc_coherent( > > - stream->dev->udev, stream->urb_size, > > - gfp_flags | __GFP_NOWARN, &uvc_urb->dma); > > -#else > > - uvc_urb->buffer = > > - kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN); > > -#endif > > - if (!uvc_urb->buffer) { > > + if (!uvc_alloc_urb_buffer(stream, uvc_urb, gfp_flags)) { > > uvc_free_urb_buffers(stream); > > break; > > } > > @@ -1730,12 +1770,8 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream, > > urb->context = uvc_urb; > > urb->pipe = usb_rcvisocpipe(stream->dev->udev, > > ep->desc.bEndpointAddress); > > -#ifndef CONFIG_DMA_NONCOHERENT > > urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP; > > urb->transfer_dma = uvc_urb->dma; > > -#else > > - urb->transfer_flags = URB_ISO_ASAP; > > -#endif > > urb->interval = ep->desc.bInterval; > > urb->transfer_buffer = uvc_urb->buffer; > > urb->complete = uvc_video_complete; > > @@ -1795,10 +1831,8 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream, > > > > usb_fill_bulk_urb(urb, stream->dev->udev, pipe, uvc_urb->buffer, > > size, uvc_video_complete, uvc_urb); > > -#ifndef CONFIG_DMA_NONCOHERENT > > urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; > > urb->transfer_dma = uvc_urb->dma; > > -#endif > > > > uvc_urb->urb = urb; > > } > > @@ -1895,6 +1929,7 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream, > > > > /* Submit the URBs. */ > > for_each_uvc_urb(uvc_urb, stream) { > > + uvc_urb_dma_sync(uvc_urb, true); > > ret = usb_submit_urb(uvc_urb->urb, gfp_flags); > > if (ret < 0) { > > dev_err(&stream->intf->dev, > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > > index 97df5ecd66c9a7..fec24f1eca1c96 100644 > > --- a/drivers/media/usb/uvc/uvcvideo.h > > +++ b/drivers/media/usb/uvc/uvcvideo.h > > @@ -545,7 +545,8 @@ struct uvc_copy_op { > > * @urb: the URB described by this context structure > > * @stream: UVC streaming context > > * @buffer: memory storage for the URB > > - * @dma: DMA coherent addressing for the urb_buffer > > + * @dma: Allocated DMA handle > > + * @sgt: sgt_table with the urb locations in memory > > * @async_operations: counter to indicate the number of copy operations > > * @copy_operations: work descriptors for asynchronous copy operations > > * @work: work queue entry for asynchronous decode > > @@ -556,6 +557,7 @@ struct uvc_urb { > > > > char *buffer; > > dma_addr_t dma; > > + struct sg_table *sgt; > > A forward declaration of struct sg_table with the other forward > declarations would be useful. > > > > > unsigned int async_operations; > > struct uvc_copy_op copy_operations[UVC_MAX_PACKETS]; -- Regards, Laurent Pinchart