Re: aac(4) resource FIB starvation on BUS scan revisited

On Dec 7, 2009, at 5:31 PM, Jung-uk Kim wrote:
> On Monday 07 December 2009 05:30 pm, Alexander Sack wrote:
>> On Mon, Dec 7, 2009 at 4:42 PM, Alexander Sack <pisymbol_at_gmail.com>
> wrote:
>>> Folks:
>>>
>>> I posted a similar thread on freebsd-scsi only to realize that
>>> scottl had fixed my first issue during some MP CAM cleanup with
>>> respect to a race during resource allocation issues on a later
>>> version of the driver we are using (I believe we did the same
>>> thing to resolve a lock issue on bootup).
>>>
>>> However on my RELENG_8 box with (2) Adaptec 5085s connected to
>>> some JBODs (9TB each) I still have a FIB starvation issue during
>>> the LUN scan:
>>>
>>> The number of FIBs allocated to this card is 512 (older cards are
>>> 256).  The max_target per bus is 287.  On a six channel
>>> controller with a BUS scan done in parallel I see a lot of this:
>>>
>>> ...
>>> (probe501:aacp1:0:214:0): Request Requeued
>>> (probe501:aacp1:0:214:0): Retrying Command
>>> (probe520:aacp1:0:233:0): Request Requeued
>>> (probe520:aacp1:0:233:0): Retrying Command
>>> (probe528:aacp1:0:241:0): Request Requeued
>>> (probe528:aacp1:0:241:0): Retrying Command
>>> (probe540:aacp1:0:253:0): Request Requeued
>>> (probe540:aacp1:0:253:0): Retrying Command
>>> (probe541:aacp1:0:254:0): Request Requeued
>>> (probe541:aacp1:0:254:0): Retrying Command
>>> ....
>>>
>>> I think the driver is much happier with the following attached
>>> patch (with dmesg).
>>
>> Patch again but this time not base-64 encoded:
>
> [SNIP!]
>
> I want it to be little conservative here, i.e., pre-allocating half of
> max_fibs.  Will the attached patch work for you?

The FIB allocation scheme was written when it was common for machines  
to only have 64MB of RAM and proportionally less KVA, so 256KB or  
512KB was a lot of RAM to wire down.  Those days have probably passed.

Scott