Re: çå: Re: [PATCH v2] scsi: Introduce sdev_printk_ratelimited to throttlefrequent printk

From: Sergey Senozhatsky
Date: Mon Apr 02 2018 - 01:29:29 EST


On (04/02/18 13:14), wen.yang99@xxxxxxxxxx wrote:
>
> > It's true that this print for the same device is useless. But it's
> > useful for different devices. Is it possible to limit the print only
> > for the same device?
>
> In our scene, it's  just for the same device (q->queuedata), Thanks.

Yes, what Jason meant was that rate limit struct is shared by different call
sites - including scsi_request_fn() from different devices.

If device1->scsi_request_fn()->sdev_printk_ratelimited() causes printk rate
limit, then messages from device2->scsi_request_fn()->sdev_printk_ratelimited()
may be lost entirely, unless you have enough of them.

-ss