| Message ID | 20210128145837.2250561-7-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/6] dma-mapping: remove the {alloc,free}_noncoherent methods | expand |
I just included this patch as-is, but here are a few comments: On Thu, Jan 28, 2021 at 03:58:37PM +0100, Christoph Hellwig wrote: > +static void uvc_urb_dma_sync(struct uvc_urb *uvc_urb, bool for_device) > +{ > + struct device *dma_dev = dma_dev = stream_to_dmadev(uvc_urb->stream); > + > + if (for_device) > + dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt, > + DMA_FROM_DEVICE); > + else > + dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt, > + DMA_FROM_DEVICE); > +} Given that we vmap the addresses this also needs flush_kernel_vmap_range / invalidate_kernel_vmap_range calls for VIVT architectures.
On Thu, Jan 28, 2021 at 4:03 PM Christoph Hellwig <hch@lst.de> wrote: > > From: Ricardo Ribalda <ribalda@chromium.org> > > On architectures where the is no coherent caching such as ARM use the > dma_alloc_noncontiguos API and handle manually the cache flushing using > dma_sync_sgtable(). > > With this patch on the affected architectures we can measure up to 20x > performance improvement in uvc_video_copy_data_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 <ribalda@chromium.org> > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/media/usb/uvc/uvc_video.c | 76 ++++++++++++++++++++++--------- > drivers/media/usb/uvc/uvcvideo.h | 4 +- > 2 files changed, 57 insertions(+), 23 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c > index a6a441d92b9488..9c051b55dc7bc6 100644 > --- a/drivers/media/usb/uvc/uvc_video.c > +++ b/drivers/media/usb/uvc/uvc_video.c > @@ -11,6 +11,7 @@ > #include <linux/module.h> > #include <linux/slab.h> > #include <linux/usb.h> > +#include <linux/usb/hcd.h> > #include <linux/videodev2.h> > #include <linux/vmalloc.h> > #include <linux/wait.h> > @@ -1097,6 +1098,23 @@ 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 = dma_dev = stream_to_dmadev(uvc_urb->stream); > + > + if (for_device) > + dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt, > + DMA_FROM_DEVICE); > + else > + dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt, > + DMA_FROM_DEVICE); > +} > + > /* > * uvc_video_decode_data_work: Asynchronous memcpy processing > * > @@ -1118,6 +1136,8 @@ 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) > uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n", > @@ -1539,10 +1559,12 @@ 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) > uvc_printk(KERN_ERR, > @@ -1559,24 +1581,47 @@ static void uvc_video_complete(struct urb *urb) > */ > static void uvc_free_urb_buffers(struct uvc_streaming *stream) > { > + struct device *dma_dev = 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, > + uvc_urb->dma, DMA_BIDIRECTIONAL); Maybe DMA_FROM_DEVICE instead of DMA_BIDIRECTIONAL ? > + > uvc_urb->buffer = NULL; > } > > 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); > + > + > + uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size, > + &uvc_urb->dma, DMA_BIDIRECTIONAL, > + gfp_flags); > + if (!uvc_urb->sgt) > + return false; > + > + 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, uvc_urb->dma, > + DMA_BIDIRECTIONAL); > + 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 > @@ -1607,19 +1652,11 @@ 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; > 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; > } > @@ -1728,12 +1765,8 @@ 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; > @@ -1793,10 +1826,8 @@ 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; > } > @@ -1891,6 +1922,7 @@ 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) { > uvc_printk(KERN_ERR, "Failed to submit URB %u (%d).\n", > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > index a3dfacf069c44d..a386114bd22999 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -521,7 +521,8 @@ 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 > @@ -532,6 +533,7 @@ struct uvc_urb { > > char *buffer; > dma_addr_t dma; > + struct sg_table *sgt; > > unsigned int async_operations; > struct uvc_copy_op copy_operations[UVC_MAX_PACKETS]; > -- > 2.29.2 >
HI Christoph Thanks for your comments On Thu, Jan 28, 2021 at 4:09 PM Christoph Hellwig <hch@lst.de> wrote: > > I just included this patch as-is, but here are a few comments: > > On Thu, Jan 28, 2021 at 03:58:37PM +0100, Christoph Hellwig wrote: > > +static void uvc_urb_dma_sync(struct uvc_urb *uvc_urb, bool for_device) > > +{ > > + struct device *dma_dev = dma_dev = stream_to_dmadev(uvc_urb->stream); > > + > > + if (for_device) > > + dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt, > > + DMA_FROM_DEVICE); > > + else > > + dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt, > > + DMA_FROM_DEVICE); > > +} > > Given that we vmap the addresses this also needs > flush_kernel_vmap_range / invalidate_kernel_vmap_range calls for > VIVT architectures. We only read from the device to the cpu. Then can we run only invalidate_kernel_vmap_range() ? something like ? 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 ); } Thanks! -- Ricardo Ribalda
On Thu, Jan 28, 2021 at 06:00:57PM +0100, Ricardo Ribalda wrote: > > Given that we vmap the addresses this also needs > > flush_kernel_vmap_range / invalidate_kernel_vmap_range calls for > > VIVT architectures. > > We only read from the device to the cpu. Then can we run only > invalidate_kernel_vmap_range() ? > > something like ? > 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 ); > } Yes. Right now we don't have a proper state machine for the *_kernel_vmap_range, but we should probably add one once usage of this grows. Until then I need to respin my API patch to document how callers need to use *_kernel_vmap_range, as well as adding the so far missing dma-debug support. As we're getting toward the end of the merge window I'll try to get this done ASAP. How should we plan to merge this code? Do you have a tree you'd like to pick up the whole thing for? Or should I create a dma-mapping tree branch that can be pulled in?
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index a6a441d92b9488..9c051b55dc7bc6 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -11,6 +11,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/usb.h> +#include <linux/usb/hcd.h> #include <linux/videodev2.h> #include <linux/vmalloc.h> #include <linux/wait.h> @@ -1097,6 +1098,23 @@ 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 = dma_dev = stream_to_dmadev(uvc_urb->stream); + + if (for_device) + dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt, + DMA_FROM_DEVICE); + else + dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt, + DMA_FROM_DEVICE); +} + /* * uvc_video_decode_data_work: Asynchronous memcpy processing * @@ -1118,6 +1136,8 @@ 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) uvc_printk(KERN_ERR, "Failed to resubmit video URB (%d).\n", @@ -1539,10 +1559,12 @@ 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) uvc_printk(KERN_ERR, @@ -1559,24 +1581,47 @@ static void uvc_video_complete(struct urb *urb) */ static void uvc_free_urb_buffers(struct uvc_streaming *stream) { + struct device *dma_dev = 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, + uvc_urb->dma, DMA_BIDIRECTIONAL); + uvc_urb->buffer = NULL; } 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); + + + uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size, + &uvc_urb->dma, DMA_BIDIRECTIONAL, + gfp_flags); + if (!uvc_urb->sgt) + return false; + + 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, uvc_urb->dma, + DMA_BIDIRECTIONAL); + 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 @@ -1607,19 +1652,11 @@ 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; 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; } @@ -1728,12 +1765,8 @@ 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; @@ -1793,10 +1826,8 @@ 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; } @@ -1891,6 +1922,7 @@ 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) { uvc_printk(KERN_ERR, "Failed to submit URB %u (%d).\n", diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h index a3dfacf069c44d..a386114bd22999 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -521,7 +521,8 @@ 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 @@ -532,6 +533,7 @@ struct uvc_urb { char *buffer; dma_addr_t dma; + struct sg_table *sgt; unsigned int async_operations; struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];