From: Takashi Iwai <tiwai@suse.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>,
perex@perex.cz, anna-maria@linutronix.de,
alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
peterz@infradead.org, mingo@redhat.com, hch@lst.de,
keescook@chromium.org, john.stultz@linaro.org,
tglx@linutronix.de
Subject: Re: [PATCH 23/25 v2] ALSA/dummy: Replace tasklet with softirq hrtimer
Date: Tue, 05 Sep 2017 18:02:36 +0200 [thread overview]
Message-ID: <s5h4lshm8v7.wl-tiwai@suse.de> (raw)
In-Reply-To: <20170905155351.2xmwyxrirndfwtgo@breakpoint.cc>
On Tue, 05 Sep 2017 17:53:51 +0200,
Sebastian Andrzej Siewior wrote:
>
> From: Thomas Gleixner <tglx@linutronix.de>
>
> The tasklet is used to defer the execution of snd_pcm_period_elapsed() to
> the softirq context. Using the CLOCK_MONOTONIC_SOFT base invokes the timer
> callback in softirq context as well which renders the tasklet useless.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
> Cc: Jaroslav Kysela <perex@perex.cz>
> Cc: Takashi Iwai <tiwai@suse.com>
> Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> Cc: alsa-devel@alsa-project.org
> [o-takashi: avoid stall due to a call of hrtimer_cancel() on a callback
> of hrtimer]
> Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
> On 2017-09-02 10:19:45 [+0900], Takashi Sakamoto wrote:
> > Yep. I request the authors to include this
> Thank you for providing a fix.
>
> v1…v2: merged Takashi Sakamoto fixup of the original patch into v2.
>
> So this patch now is okay?
Note that you can try it by yourself easily, as it's a dummy driver
that doesn't need anything special. Just run aplay for that device
(e.g. aplay -Dplughw:2 for card#2) can reproduce the original
problem.
> @@ -394,7 +386,12 @@ static enum hrtimer_restart dummy_hrtimer_callback(struct hrtimer *timer)
> dpcm = container_of(timer, struct dummy_hrtimer_pcm, timer);
> if (!atomic_read(&dpcm->running))
> return HRTIMER_NORESTART;
> - tasklet_schedule(&dpcm->tasklet);
> +
> + /* In a case of XRUN, this calls .trigger to stop PCM substream. */
As mentioned, the stop happens not only with XRUN but also in a normal
situation by draining.
Other than that, looks OK to me (but not tested it).
thanks,
Takashi
> + snd_pcm_period_elapsed(dpcm->substream);
> + if (!atomic_read(&dpcm->running))
> + return HRTIMER_NORESTART;
> +
> hrtimer_forward_now(timer, dpcm->period_time);
> return HRTIMER_RESTART;
> }
> @@ -414,14 +411,14 @@ static int dummy_hrtimer_stop(struct snd_pcm_substream *substream)
> struct dummy_hrtimer_pcm *dpcm = substream->runtime->private_data;
>
> atomic_set(&dpcm->running, 0);
> - hrtimer_cancel(&dpcm->timer);
> + if (!hrtimer_callback_running(&dpcm->timer))
> + hrtimer_cancel(&dpcm->timer);
> return 0;
> }
>
> static inline void dummy_hrtimer_sync(struct dummy_hrtimer_pcm *dpcm)
> {
> hrtimer_cancel(&dpcm->timer);
> - tasklet_kill(&dpcm->tasklet);
> }
>
> static snd_pcm_uframes_t
> @@ -466,12 +463,10 @@ static int dummy_hrtimer_create(struct snd_pcm_substream *substream)
> if (!dpcm)
> return -ENOMEM;
> substream->runtime->private_data = dpcm;
> - hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> + hrtimer_init(&dpcm->timer, CLOCK_MONOTONIC_SOFT, HRTIMER_MODE_REL);
> dpcm->timer.function = dummy_hrtimer_callback;
> dpcm->substream = substream;
> atomic_set(&dpcm->running, 0);
> - tasklet_init(&dpcm->tasklet, dummy_hrtimer_pcm_elapsed,
> - (unsigned long)dpcm);
> return 0;
> }
>
> --
> 2.14.1
>
next prev parent reply other threads:[~2017-09-05 16:02 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-31 12:23 [PATCH 00/25] hrtimer: Provide softirq context hrtimers Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 01/25] hrtimer: Use predefined function for updating next_timer Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 02/25] hrtimer: Correct blantanly wrong comment Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 03/25] hrtimer: Fix kerneldoc for struct hrtimer_cpu_base Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 04/25] hrtimer: Cleanup clock argument in schedule_hrtimeout_range_clock() Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 05/25] hrtimer: Switch for loop to _ffs() evaluation Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 07/25] hrtimer: Reduce conditional code (hres_active) Anna-Maria Gleixner
2017-09-25 13:55 ` Peter Zijlstra
2017-09-25 14:28 ` Thomas Gleixner
2017-08-31 12:23 ` [PATCH 06/25] hrtimer: Store running timer in hrtimer_clock_base Anna-Maria Gleixner
2017-09-25 14:44 ` Peter Zijlstra
2017-09-28 12:45 ` Thomas Gleixner
2017-08-31 12:23 ` [PATCH 08/25] hrtimer: Reduce conditional code (expires_next, next_timer) Anna-Maria Gleixner
2017-09-26 12:10 ` Peter Zijlstra
2017-09-28 8:07 ` Thomas Gleixner
2017-08-31 12:23 ` [PATCH 09/25] hrtimer: Reduce conditional code (hrtimer_reprogram()) Anna-Maria Gleixner
2017-09-26 12:07 ` Peter Zijlstra
2017-08-31 12:23 ` [PATCH 10/25] hrtimer: Make handling of hrtimer reprogramming and enqueuing not conditional Anna-Maria Gleixner
2017-09-26 12:14 ` Peter Zijlstra
2017-09-28 8:09 ` Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 11/25] hrtimer: Allow remote hrtimer enqueue with "expires_next" as expiry time Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 13/25] hrtimer: Split out code from hrtimer_start_range_ns() for reuse Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 12/25] hrtimer: Simplify hrtimer_reprogram() call Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 14/25] hrtimer: Split out code from __hrtimer_get_next_event() for reuse Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 15/25] hrtimer: Add clock bases for soft irq context Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 16/25] hrtimer: Allow function reuse for softirq based hrtimer Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 18/25] hrtimer: Enable soft and hard hrtimer Anna-Maria Gleixner
2017-09-26 12:52 ` Peter Zijlstra
2017-09-27 14:18 ` Anna-Maria Gleixner
2017-09-27 15:54 ` Thomas Gleixner
2017-09-27 16:47 ` Peter Zijlstra
2017-08-31 12:23 ` [PATCH 17/25] hrtimer: Implementation of softirq hrtimer handling Anna-Maria Gleixner
2017-09-26 12:40 ` Peter Zijlstra
2017-09-26 15:03 ` Peter Zijlstra
2017-09-27 14:22 ` Anna-Maria Gleixner
2017-09-27 16:46 ` Peter Zijlstra
2017-09-27 16:40 ` Peter Zijlstra
2017-09-28 7:59 ` Thomas Gleixner
2017-09-28 8:15 ` Peter Zijlstra
2017-12-19 8:58 ` Sebastian Andrzej Siewior
2017-12-19 13:21 ` Peter Zijlstra
2017-12-20 8:44 ` Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 20/25] mac80211_hwsim: Replace hrtimer tasklet with softirq hrtimer Anna-Maria Gleixner
2017-09-05 7:03 ` Johannes Berg
2017-09-05 8:49 ` Thomas Gleixner
2017-09-05 8:51 ` Johannes Berg
2017-08-31 12:23 ` [PATCH 19/25] can/bcm: Replace hrtimer_tasklet with softirq based hrtimer Anna-Maria Gleixner
2017-09-01 15:49 ` Oliver Hartkopp
2017-09-01 15:56 ` Thomas Gleixner
2017-09-01 17:02 ` Oliver Hartkopp
2017-09-02 17:56 ` Oliver Hartkopp
2017-08-31 12:23 ` [PATCH 21/25] xfrm: Replace hrtimer tasklet with softirq hrtimer Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 23/25] ALSA/dummy: Replace " Anna-Maria Gleixner
2017-08-31 14:21 ` Takashi Sakamoto
2017-08-31 14:26 ` Takashi Iwai
2017-08-31 15:36 ` Takashi Iwai
2017-09-01 10:25 ` Takashi Sakamoto
2017-09-01 11:58 ` Takashi Iwai
2017-09-02 1:19 ` Takashi Sakamoto
2017-09-04 12:45 ` Takashi Sakamoto
2017-09-05 15:53 ` [PATCH 23/25 v2] " Sebastian Andrzej Siewior
2017-09-05 16:02 ` Takashi Iwai [this message]
2017-09-05 16:05 ` Takashi Sakamoto
2017-09-05 16:18 ` [PATCH 23/25 v3] " Sebastian Andrzej Siewior
2017-09-06 4:30 ` Takashi Sakamoto
2017-09-08 8:28 ` [alsa-devel] " Takashi Iwai
2017-08-31 12:23 ` [PATCH 22/25] softirq: Remove tasklet_hrtimer Anna-Maria Gleixner
2017-08-31 12:23 ` [PATCH 25/25] usb/gadget/NCM: Replace tasklet with softirq hrtimer Anna-Maria Gleixner
2017-10-24 9:45 ` Felipe Balbi
2017-08-31 12:23 ` [PATCH 24/25] net/cdc_ncm: " Anna-Maria Gleixner
2017-08-31 13:33 ` Greg Kroah-Hartman
2017-08-31 13:57 ` Bjørn Mork
2017-09-05 15:42 ` [PATCH 24/25 v2] " Sebastian Andrzej Siewior
2017-08-31 12:36 ` [PATCH 00/25] hrtimer: Provide softirq context hrtimers Anna-Maria Gleixner
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