Re: [PATCH 02/11] libata-eh: implement ata_ering

[Tejun Heo <htejun@gmail.com>]

Alan Cox wrote:
> On Llu, 2006-05-15 at 23:25 +0900, Tejun Heo wrote:
>> I was too quick to response.  ering keeps track of timestamps of each
>> error and the criteria for speeding down is something like "3 class 1
>> errors during last 15mins", so bitmaps doesn't cut it.
> 
> Sounds like it does
> 
> 
> 	log_class_1_error(dev)
> 	{
> 		if((dev->class1 & 3) < 3) {
> 			dev->class1++;
> 			dev->class1sum++;
> 		} else {
> 			/* 3 this minute alone */
> 			it_happened_now_case();
> 		}
> 	}
> 
> 	class_1_each_minute(dev)
> 	{
> 		dev->class1sum -= (dev->class1 >> 30);
> 		dev->class1 <<= 2;
> 	}
> 

Yeap, of course, it does with periodic shifting.  The 3 in this minute
testing looks neat.

I don't know.  I'm still a bit hesitant because the thing becomes a
little bit more complex (it has more moving parts) and it would be
difficult to define/tune speed down or any other error handling (say,
turning off NCQ) criteria.  But, I might be planning too much.

-- 
tejun