Re: [Xen-devel] [xen-devel] create irq failed due to move_cleanup_count always being set

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 04/01/12 11:38, Andrew Cooper wrote:
> On 04/01/12 04:37, Liuyongan wrote:
>> Hi, all
>>    
>>     I'm using xen-4.0 to do a test. And when I create a domain, it failed 
>> due to create_irq() failure. As only 33 domains were successfully created 
>> and destroyed before I got the continuous failures, and the domain just 
>> before the failure was properly destroyed(at least destroy_irq() was 
>> properly called, which will clear move_in_progress, according to the 
>> prink-message). So I can conclude for certain that __assign_irq_vector 
>> failed due to move_cleanup_count always being set.
> Is it always 33 domains it takes to cause the problem, or does it vary? 
> If it varies, then I think you want this patch
> http://xenbits.xensource.com/hg/xen-unstable.hg/rev/68b903bb1b01 which
> corrects the logic which works out which moved vectors it should clean
> up.  Without it, stale irq numbers build up in the per-cpu irq_vector
> tables leading to __assign_irq_vector failing with -ENOSPC as it find
> find a vector to allocate.

P.S. Sorry - I mean the per-cpu vector_irq tables.  The irq_vector table
is something different.

~Andrew

>> //this is the normal case when create and destroy domain whose id is 31;
>> (XEN) irq.c:1232:d0 bind pirq 79, irq 77, share flag:0
>> (XEN) irq.c:1377: dom31: pirq 79, irq 77 force unbind
>> (XEN) irq.c:1593: dom31: forcing unbind of pirq 79
>> (XEN) irq.c:223, destroy irq 77
>>
>> //domain id 32 is created and destroyed correctly also.
>> (XEN) irq.c:1232:d0 bind pirq 79, irq 77, share flag:0
>> (XEN) irq.c:1377: dom32: pirq 79, irq 77 force unbind
>> (XEN) irq.c:1593: dom32: forcing unbind of pirq 79
>> (XEN) irq.c:223, destroy irq 77
>>
>> //all the subsequent domain creation failed, below lists only 3 times:
>> (XEN) physdev.c:88: dom33: can't create irq for msi!
>> (XEN) physdev.c:88: dom34: can't create irq for msi!
>> (XEN) physdev.c:88: dom35: can't create irq for msi!
>>
>>      I think this might be a bug and might have fixed, so I compare my code 
>> with 4.1.2 and search the mail list for potential patches. 
>> (http://xen.markmail.org/search/?q=move_cleanup_count#query:move_cleanup_count+page:6+mid:fpkrafqbeyiauvhs+state:results)
>>  submit a patch which add locks in __assign_irq_vector. Can anybody explain 
>> why this lock is needed? Or is there a patch that might fix my bug? Thx.
> This patch fixes a problem where IOAPIC line level interrupts cease for
> a while.  It has nothing to do with MSI interrupts.  (Also, there are no
> locks altered, and xen-4.0-testing seems to have gained an additional
> hunk in hvm/vmx code unrelated to the original patch.)
>
>>     Addition message: my board is arch-x86, no domains left when failed to 
>> create new ones, create_irq failure lasted one day until I reboot the board, 
>> and the irq number allocated is used certainly for a msi dev.
>>
>> Yong an Liu
>> 2012.1.4
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com


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