Re: [win-pv-devel] lost SRB in xenvbd

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: win-pv-devel [mailto:win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx] On
> Behalf Of Andreas Kinzler
> Sent: 13 February 2017 16:34
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: [win-pv-devel] lost SRB in xenvbd
> 
> After days of debugging I find that xenvbd is causing hangs no matter if
> Xen 4.8.0, 4.7.1 or 4.5.1. In any case I see PdoResets
> 
> XENVBD|__PdoReset:Target[1] ====>
> XENVBD|PdoReset:Target[1] ====> (Irql=2)
> XENVBD|__PdoPauseDataPath:Target[1] : Waiting for 0 Submitted requests
> XENVBD|__PdoPauseDataPath:Target[1] : 0/0 Submitted requests left (0
> iterrations)
> XENVBD|PdoReset:Target[1] <==== (Irql=2)
> XENVBD|__PdoReset:Target[1] <====
> 
> The MSDN doc says a PDO reset is triggered if a SRB times out. In any
> hang I always see the following line:
> 
> XENVBD: FDO: Srbs            : 1 / 254 (12166611 Total)
> 

Owen,

  Does this tally with the issue you're looking at?

  Paul

>  From what I read in the driver source code this means that there is one
> SRB pending. But nothing is in the queues, rings, ... (see below). I
> assume that SRB has been lost somewhere?
> 
> Any help greatly appreciated.
> 
> BTW: Disabling discard caused the hang to appear quite rapidly (only one
> debug pass so far)
> 
> Regards Andreas
> 
> XENVBD: LOOKASIDE: REQUESTs: 0 / 83 (0 failed)
> XENVBD: LOOKASIDE: SEGMENTs: 0 / 888 (0 failed)
> XENVBD: LOOKASIDE: INDIRECTs: 0 / 0 (0 failed)
> XENVBD: QUEUE: Fresh     : 0 / 33
> XENVBD: QUEUE: Prepared  : 0 / 51
> XENVBD: QUEUE: Submitted : 0 / 36
> XENVBD: QUEUE: Shutdown  : 0 / 0
> XENVBD: FRONTEND: TargetId=1 DeviceId=832 BackendId=0
> XENVBD: FRONTEND: FrontendPath device/vbd/832
> XENVBD: FRONTEND: BackendPath  /local/domain/0/backend/vbd/2/832
> XENVBD: FRONTEND: TargetPath   data/scsi/target/1
> XENVBD: FRONTEND: State   : ENABLED
> XENVBD: FRONTEND: Caps    : CONNECTED
> XENVBD: FRONTEND: Features: PERSISTENT
> XENVBD: FRONTEND: DiskInfo: 100000000 @ 512 (512) 00000000
> XENVBD: GRANTER: CONNECTED ENABLED
> XENVBD: GRANTER: 1 / 889
> XENVBD: BLOCKRING: Requests  : 65968184 / 65968184
> XENVBD: BLOCKRING: SharedRing : 0xFFFFD001935A9000
> XENVBD: BLOCKRING: SharedRing : 65974354 / 65974355 - 65974354 /
> 65974355
> XENVBD: BLOCKRING: FrontRing  : 65974354 / 65974354 (32)
> XENVBD: BLOCKRING: Order      : 0
> XENVBD: BLOCKRING: Grants[0 ] : 0xFFFFE001E17B7B88 (33)
> XENVBD: NOTIFIER: Int / DPC : 56337743 / 64634483
> XENVBD: NOTIFIER: Channel : FFFFE001E17A76D0 (10)
> 
> 
> 
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