cvs commit: src/sys/kern kern_intr.c

[Scott Long]

John Baldwin wrote:
> On Friday 02 March 2007 13:45, Scott Long wrote:
>> John Baldwin wrote:
>>> On Friday 02 March 2007 12:28, Kris Kennaway wrote:
>>>> On Fri, Mar 02, 2007 at 10:13:54AM -0700, Scott Long wrote:
>>>>> John Baldwin wrote:
>>>>>> jhb         2007-03-02 17:01:45 UTC
>>>>>>
>>>>>>  FreeBSD src repository
>>>>>>
>>>>>>  Modified files:
>>>>>>    sys/kern             kern_intr.c 
>>>>>>  Log:
>>>>>>  - Don't do the interrupt storm protection stuff for software interrupt
>>>>>>    handlers.
>>>>>>  - Use pause() when throtting during an interrupt storm.
>>>>>>  
>>>>>>  Reported by:    kris (1)
>>>>>>  
>>>>>>  Revision  Changes    Path
>>>>>>  1.142     +3 -2      src/sys/kern/kern_intr.c
>>>>> Actually, having this helped detect a problem with a CAM driver.
>>>>>
>>>>> Scott
>>>> I saw it under normal operation when doing a lot of loopback traffic
>>>> on an 8-core.
>>> Also, if it ever kicked in for softclock, the system would deadlock.
>>>
>> Can it be selectively enabled?
> 
> We could do that, sure.  The original intent was to prevent a storming 
> level-triggered PCI interrupt to hang the machine though.  It was never 
> really intended for swi's and having it be on for swi's was an oversight on 
> my part.
> 

It could be argued that "storming" on the swi is also a bug.  It 
certainly was for a misbehaving driver recently.

Scott