From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82DFBC433EF for ; Tue, 19 Apr 2022 20:47:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357704AbiDSUtn (ORCPT ); Tue, 19 Apr 2022 16:49:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357370AbiDSUtm (ORCPT ); Tue, 19 Apr 2022 16:49:42 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39E4D4130B for ; Tue, 19 Apr 2022 13:46:59 -0700 (PDT) Received: from pendragon.ideasonboard.com (85-76-5-145-nat.elisa-mobile.fi [85.76.5.145]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E1A1425B; Tue, 19 Apr 2022 22:46:56 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1650401217; bh=Z7qVvTmzcoWqIVhENl92K6hHEseW+EyMDZ+60xOGgCs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kaJikOH29TQHROac3A5BTz58lYtZjBkgfzIzyFFIorEig/8M9eq2lCGTAJygaVSuB g9YlMYK8Tm7oiMFMqLwRjPEVP6/MJToell5d3++Oi5LEKFISZXOyuuaYXef3W0h98j wyfCeBbEX3ZkXKWtUooYeON9NjxIdajs9FgBI8SQ= Date: Tue, 19 Apr 2022 23:46:57 +0300 From: Laurent Pinchart To: Michael Grzeschik Cc: linux-usb@vger.kernel.org, balbi@kernel.org, paul.elder@ideasonboard.com, kernel@pengutronix.de, nicolas@ndufresne.ca, kieran.bingham@ideasonboard.com Subject: Re: [PATCH 3/5] usb: gadget: uvc: increase worker prio to WQ_HIGHPRI Message-ID: References: <20220402233914.3625405-1-m.grzeschik@pengutronix.de> <20220402233914.3625405-4-m.grzeschik@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220402233914.3625405-4-m.grzeschik@pengutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hi Michael, Thank you for the patch. On Sun, Apr 03, 2022 at 01:39:12AM +0200, Michael Grzeschik wrote: > Likewise to the uvcvideo hostside driver, this patch is changing the > simple workqueue to an async_wq with higher priority. This ensures that > the worker will not be scheduled away while the video stream is handled. > > Signed-off-by: Michael Grzeschik > --- > drivers/usb/gadget/function/uvc.h | 1 + > drivers/usb/gadget/function/uvc_v4l2.c | 2 +- > drivers/usb/gadget/function/uvc_video.c | 9 +++++++-- > 3 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index c3607a32b98624..ab537acdae3184 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -86,6 +86,7 @@ struct uvc_video { > struct usb_ep *ep; > > struct work_struct pump; > + struct workqueue_struct *async_wq; > > /* Frame parameters */ > u8 bpp; > diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c > index a2c78690c5c288..9b1488f7abd736 100644 > --- a/drivers/usb/gadget/function/uvc_v4l2.c > +++ b/drivers/usb/gadget/function/uvc_v4l2.c > @@ -170,7 +170,7 @@ uvc_v4l2_qbuf(struct file *file, void *fh, struct v4l2_buffer *b) > return ret; > > if (uvc->state == UVC_STATE_STREAMING) > - schedule_work(&video->pump); > + queue_work(video->async_wq, &video->pump); > > return ret; > } > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c > index 7f59a0c4740209..b1075e23a61010 100644 > --- a/drivers/usb/gadget/function/uvc_video.c > +++ b/drivers/usb/gadget/function/uvc_video.c > @@ -269,7 +269,7 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req) > spin_unlock_irqrestore(&video->req_lock, flags); > > if (uvc->state == UVC_STATE_STREAMING) > - schedule_work(&video->pump); > + queue_work(video->async_wq, &video->pump); > } > > static int > @@ -469,7 +469,7 @@ int uvcg_video_enable(struct uvc_video *video, int enable) > > video->req_int_count = 0; > > - schedule_work(&video->pump); > + queue_work(video->async_wq, &video->pump); > > return ret; > } > @@ -483,6 +483,11 @@ int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc) > spin_lock_init(&video->req_lock); > INIT_WORK(&video->pump, uvcg_video_pump); > > + /* Allocate a stream specific work queue for asynchronous tasks. */ You can drop the "stream" here. The gadget driver handles a single stream. > + video->async_wq = alloc_workqueue("uvcvideo", WQ_UNBOUND | WQ_HIGHPRI, 0); Unless I'm mistaken, an unbound work queue means that multiple CPUs will handle tasks in parallel. Is that safe ? > + if (!video->async_wq) > + return -EINVAL; No need to destroy the work queue somewhere ? > + > video->uvc = uvc; > video->fcc = V4L2_PIX_FMT_YUYV; > video->bpp = 16; -- Regards, Laurent Pinchart