Re: [PATCHv2] tracing/events: Add bounce tracing to swiotbl

[Zoltan Kiss <zoltan.kiss@citrix.com>]

On 25/09/13 18:56, Konrad Rzeszutek Wilk wrote:
> On Wed, Sep 18, 2013 at 05:04:17PM +0100, Zoltan Kiss wrote:
>> Hi,
>>
>> I haven't got a reply in the past 2 weeks, so I would like to bump
>> the patch, just to make sure it haven't fell off the radar.
>
> Hey,
>
> I have this in my queue to put on 3.13 as it is past the merge window.
> .. with that in mind:
>
>
> .. snip..
>>> +	TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx "
>>> +		"size=%zu swiotlb_force=%x",
>>> +		__get_str(dev_name),
>>> +		__entry->dma_mask,
>>> +		(unsigned long long)__entry->dev_addr,
>>> +		__entry->size,
>>> +		__entry->swiotlb_force)
>
> Would it make sense to do something like this:
>
> 		__entry->swiotlb_force ? "swiotlb_force" : "")
>

I would then rather do:

+	TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx "
+		"size=%zu swiotlb_force=",
+               __entry->swiotlb_force ? " yes" : "no",
+		__get_str(dev_name),

Or do you mean?:

+	TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx "
+		"size=%zu",
+               __entry->swiotlb_force ? " swiotlb_force" : "",
+		__get_str(dev_name),

This one doesn't tell you explicitly if swiotlb_force is NOT set, maybe 
that's not so good? And adds a bit of complexity to your grep regexp?
Either way is fine with me, but I think "swiotlb_force=0|1" is also 
pretty straightforward to understand, and I guess it makes printk 
slightly faster (I assume the conditional operator gives a little bit of 
overhead)

Regards,

Zoli