From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7E1808C1E; Tue, 3 Sep 2024 13:59:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725371958; cv=none; b=dn8x31AFivQtAXccK9seyZzPkjdQFMkVyhCxet9GPZ8H5qQkcv1t4s8st+KqjVCuoJfqXWjvHvH3QO6iK+FxGU6l8+jwM8jhR3F0KaEEuD3MatMOcVn0iFugkmni7VuwGyARHk5dM7KaPucbqqK90LDJjn2a0FE6XYr2Plk7vZ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725371958; c=relaxed/simple; bh=dEf9tRqQz/W6OZFzWQPD1lKesvSyRmRiSidq/+SEC84=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TJkOLmbgUub3zjklErDwxRNO8bxKyhx7zh7KB3SLNQA+7LXdp1rqNwuGHV4cjRoB3gavkjeHFWcFomn4+1lIKQAtUGe869dInVjl84Exo6oRmdy6DeOTW/b9jnCRkLJulqpYpDUDukJ5QGSPdhVKJuJNE4keKMF4KLwPJa3pnt8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qH7sRs97; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qH7sRs97" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 903D8C4CEC4; Tue, 3 Sep 2024 13:59:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725371958; bh=dEf9tRqQz/W6OZFzWQPD1lKesvSyRmRiSidq/+SEC84=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qH7sRs97PMMF79vJ0o/S3r24Rasz0xGVR298zqCPX+dUiC3XsFjrVo69QKQvcjybP xFxnqtoMWClMNZfPBbcM/FjMtvhc6r++VEKaXpsk8z0rsOYui6HTL72dbYiFhBN0hl N3mpg4a93TwIYfPN0Z+xqc9+kif01kejr1v0T/hJzBVpPMj0N5/5lVMx/6yRiBWAuQ dKDXXdu7kdzt8QImXkVX5LJKqhFXcBpvHzFCZPrzCwNPmgXqarEPgVIloIQQ88UhMc nSP3QdESEc7uZGIBg8T1wKzxr5A59GPNzGCAg2VyHbu+GOv1eQkkRxYdlOZuf14yz7 +Su0KN+Jj0Mdg== Date: Tue, 3 Sep 2024 14:59:13 +0100 From: Lee Jones To: Dmitry Rokosov Cc: pavel@ucw.cz, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, kernel@salutedevices.com, rockosov@gmail.com, Alexey Romanov Subject: Re: ATTENTION USERS/TESTERS: Re: [PATCH v1] leds: introduce ordered workqueue for leds events instead of system_wq Message-ID: <20240903135913.GV6858@google.com> References: <20240820155407.32729-1-ddrokosov@salutedevices.com> <20240822133819.GJ6858@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240822133819.GJ6858@google.com> On Thu, 22 Aug 2024, Lee Jones wrote: > INTENTIONAL TOP POST: > > This is going to need more time on the list and hopefully draws the > attention of some potentially affected users / to-be testers. Another call for users to test this before I review/apply it. Plan is to rotate it in to -next just after -rc1 has been released. That should give it quite a few weeks in -next for people to test. > > This allows to setup ordered workqueue for leds events. This may be > > useful, because default 'system_wq' does not guarantee execution order > > of each work_struct, thus for several brightness update requests (for > > multiple leds), real brightness switch could be in random order. > > > > Yes, for sysfs-based leds we have flush_work() call inside > > brightness_store() operation, but it's blocking call, so userspace > > caller can be blocked at a long time, which means leds animation stream > > can be broken. > > > > Ordered workqueue has the same behaviour as system_wq + flush_work(), > > but all scheduled works are async and userspace caller is not blocked, > > which it better for userspace animation scheduling. > > > > Signed-off-by: Alexey Romanov > > Signed-off-by: Dmitry Rokosov > > --- > > drivers/leds/led-class.c | 12 +++++++++++- > > drivers/leds/led-core.c | 6 +++--- > > include/linux/leds.h | 1 + > > 3 files changed, 15 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c > > index ba1be15cfd8e..fba12471cf1f 100644 > > --- a/drivers/leds/led-class.c > > +++ b/drivers/leds/led-class.c > > @@ -25,6 +25,8 @@ > > static DEFINE_MUTEX(leds_lookup_lock); > > static LIST_HEAD(leds_lookup_list); > > > > +static struct workqueue_struct *leds_wq; > > + > > static ssize_t brightness_show(struct device *dev, > > struct device_attribute *attr, char *buf) > > { > > @@ -57,7 +59,6 @@ static ssize_t brightness_store(struct device *dev, > > if (state == LED_OFF) > > led_trigger_remove(led_cdev); > > led_set_brightness(led_cdev, state); > > - flush_work(&led_cdev->set_brightness_work); > > > > ret = size; > > unlock: > > @@ -549,6 +550,8 @@ int led_classdev_register_ext(struct device *parent, > > > > led_update_brightness(led_cdev); > > > > + led_cdev->wq = leds_wq; > > + > > led_init_core(led_cdev); > > > > #ifdef CONFIG_LEDS_TRIGGERS > > @@ -667,12 +670,19 @@ EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); > > > > static int __init leds_init(void) > > { > > + leds_wq = alloc_ordered_workqueue("leds", 0); > > + if (!leds_wq) { > > + pr_err("failed to create leds ordered workqueue\n"); > > + return -ENOMEM; > > + } > > + > > return class_register(&leds_class); > > } > > > > static void __exit leds_exit(void) > > { > > class_unregister(&leds_class); > > + destroy_workqueue(leds_wq); > > } > > > > subsys_initcall(leds_init); > > diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c > > index 89c9806cc97f..9769ac49be20 100644 > > --- a/drivers/leds/led-core.c > > +++ b/drivers/leds/led-core.c > > @@ -266,7 +266,7 @@ void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on > > led_cdev->delayed_delay_on = delay_on; > > led_cdev->delayed_delay_off = delay_off; > > set_bit(LED_SET_BLINK, &led_cdev->work_flags); > > - schedule_work(&led_cdev->set_brightness_work); > > + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); > > return; > > } > > > > @@ -297,7 +297,7 @@ void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness) > > */ > > if (!brightness) { > > set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); > > - schedule_work(&led_cdev->set_brightness_work); > > + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); > > } else { > > set_bit(LED_BLINK_BRIGHTNESS_CHANGE, > > &led_cdev->work_flags); > > @@ -333,7 +333,7 @@ void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value) > > set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags); > > } > > > > - schedule_work(&led_cdev->set_brightness_work); > > + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); > > } > > EXPORT_SYMBOL_GPL(led_set_brightness_nopm); > > > > diff --git a/include/linux/leds.h b/include/linux/leds.h > > index 6300313c46b7..7c9f1cb12ab9 100644 > > --- a/include/linux/leds.h > > +++ b/include/linux/leds.h > > @@ -169,6 +169,7 @@ struct led_classdev { > > int new_blink_brightness; > > void (*flash_resume)(struct led_classdev *led_cdev); > > > > + struct workqueue_struct *wq; /* LED workqueue */ > > struct work_struct set_brightness_work; > > int delayed_set_value; > > unsigned long delayed_delay_on; > > -- > > 2.43.0 > > > > > > -- > Lee Jones [李琼斯] -- Lee Jones [李琼斯]