Re: [ofa-general][PATCH 3/4] SRP fail-over faster

[Vu Pham <vuhuong-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

David Dillow wrote:
> On Thu, 2009-10-22 at 19:34 -0400, David Dillow wrote:
>   
>> On Thu, 2009-10-22 at 19:33 -0400, David Dillow wrote:
>>     
>>> On Thu, 2009-10-22 at 19:13 -0400, Vu Pham wrote:
>>>       
>>>> Jason Gunthorpe wrote:
>>>>         
>>>>> On Thu, Oct 15, 2009 at 03:25:15PM -0400, David Dillow wrote:
>>>>>           
>>>>>> I use multipath with ALUA, and I don't mind if the link flaps a bit. 60
>>>>>> seconds is near my SCSI timeout of 77 seconds, so it doesn't buy me
>>>>>> much. I'd rather multipath be delivering traffic to the backup path than
>>>>>> sitting on its thumbs for 60 seconds doing nothing.
>>>>>>             
>>>>> Certainly an enforced lower limit in the kernel is silly, and a
>>>>> per-device setting does make some sense.
>>>>>           
>>>> Here is the updated patch which implement the device_loss_timeout for 
>>>> each target instead of module parameter. It also reflects changes from 
>>>> previous feedbacks. Please review
>>>>         
>>> Please put your patches inline for ease of reply...
>>>
>>> You still seem to have a 30 second minimum timeout, and no way to
>>> disable it altogether.
>>>       
>> And if I could read a patch, I'd notice that that was not a minimum, but
>> a default. Still, I have to have a 1 second timeout with no way to
>> disable entirely. Better, but...
>>     
>
>   
Yes and you can not disable intirely. I'm still looking at 
benefits/advantages to disable it entirely

> Last time I reply to myself tonight, I promise... :/
>
> You also don't seem to use the user supplied setting, but hard code the
> time to 5 seconds?
>   

I use the user supplied setting for local async event on port error 
where link is broken from host to switch

For case link broken from target port to switch. We detect this case by 
receiving connection closed or wqe error and when this happen unknown 
certain seconds already passed by; therefore, I sleep 5 seconds instead 
of using user supplied value.

To really sleep user supplied number of seconds, we need to register 
trap to SM and receiving trap for a node leaving the fabric.
It requires a lot of changes in srp_daemon (registering to trap, passing 
event down to srp driver) and srp driver (handling this event)


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