Re: [PATCH v4 4/5] block: introduce LED block device activity trigger

Pavel Machek
2019-08-17T14:55:12Z

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On Fri 2019-08-16 01:59:58, Akinobu Mita wrote:
> This allows LEDs to be controlled by block device activity.
>
> We already have ledtrig-disk (LED disk activity trigger), but the lower
> level disk drivers need to utilize ledtrig_disk_activity() to make the
> LED blink.
>
> The LED block device trigger doesn't require the lower level drivers to
> have any instrumentation. The activity is collected by polling the disk
> stats.
>
> Example:
>
> echo block-nvme0n1 > /sys/class/leds/diy/trigger

Lets use one trigger "block" and have the device as a parameter,
please.

We already have 1000 cpu triggers on 1000 cpu machines, and yes, its a
disaster we'll need to fix. Lets not repeat the same mistake here.

I guess it may be slightly more work. Sorry about that.

Pavel

> +++ b/include/linux/leds.h
> +#else
> +
> +struct ledtrig_blk {
> +};
> +

Is the empty struct neccessary?

> +static inline void ledtrig_blk_enable(struct gendisk *disk)
> +{
> +}
> +
> +static inline void ledtrig_blk_disable(struct gendisk *disk)
> +{
> +}
> +
> +static inline int ledtrig_blk_register(struct gendisk *disk)
> +{
> + return 0;
> +}
> +
> +static inline void ledtrig_blk_unregister(struct gendisk *disk)
> +{
> +}

Normally we put such empty functions on single lines...

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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