linux-kernel - Re: [alsa-devel] [PATCH] sound: soc: intel: bxt_da7219_max98357a: Replace GFP_ATOMIC with GFP_KERNEL in broxton_audio

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Date:   Mon, 09 Apr 2018 21:39:06 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     "Pierre-Louis Bossart" <pierre-louis.bossart@...ux.intel.com>
Cc:     <Adam.Thomson.Opensource@...semi.com>,
        "Jia-Ju Bai" <baijiaju1990@...il.com>, <lgirdwood@...il.com>,
        <sathyanarayana.nujella@...el.com>, <broonie@...nel.org>,
        <perex@...ex.cz>, <alsa-devel@...a-project.org>,
        "Vinod Koul" <vinod.koul@...el.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [alsa-devel] [PATCH] sound: soc: intel: bxt_da7219_max98357a: Replace GFP_ATOMIC with GFP_KERNEL in broxton_audio_probe

On Mon, 09 Apr 2018 20:57:43 +0200,
Pierre-Louis Bossart wrote:
> 
> On 4/9/18 5:46 AM, Jia-Ju Bai wrote:
> > broxton_audio_probe() is never called in atomic context.
> > This function is only set as ".probe" in "struct platform_driver".
> >
> > Despite never getting called from atomic context,
> > broxton_audio_probe() calls devm_kzalloc() with GFP_ATOMIC,
> > which waits busily for allocation.
> > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> > to avoid busy waiting and improve the possibility of sucessful allocation.
> 
> [answering for the series]
> Humm, this is interesting.
> If indeed we can afford to sleep then the change should be done on ALL
> 14 boards in sound/soc/intel/boards which follow the same code
> pattern.
> If we cannot sleep then then none of these changes should be applied.
> Liam and Vinod?

It must be sleepable context as it's a standard platform driver probe
callback.

And now looking at grep output, only sound/soc/intel contains so many
calls with GFP_ATOMIC.  I bet that almost all can be done with
GFP_KERNEL, maybe only one or two in atom/sst would be conditionally
with GFP_ATOMIC.


thanks,

Takashi