On Wed, Aug 5, 2009 at 6:19 PM, Mike Christie<micha...@cs.wisc.edu> wrote:
> On 08/04/2009 01:12 PM, Erez Zilber wrote:
>> On Tue, Aug 4, 2009 at 8:17 PM, Mike Christie<micha...@cs.wisc.edu>  wrote:
>>> Erez Zilber wrote:
>>>> I'm running with open-iscsi.git HEAD + the check suspend bit patch +
>>>> the wake xmit on error patch. If I disconnect the cable on the
>>>> initiator side (even while not running IO), I see that after sending
>>>> the signal, the  iscsi_q_XX thread reaches 100% cpu. I ran it over
>>>> several 1GB/ 10 GB drivers and got the same results.
>>>> If I remove the  wake xmit on error patch, I don't see this behavior.
>>> Shoot, I have been running the xmit wakeup and suspend bit patch here
>>> fine. Let me do some more testing.
>>> Is this something you always hit? Could you send me the final patch you
>>> ended up using?
>> I see this every time. Note that I'm not running with
>> linux-2.6-iscsi.git. I'm using the open-iscsi.git tree + the 2 patches
>> that I took without any change (using git-show) from the
>> linux-2.6-iscsi.git tree. Which tree did you test it on?
>> I added some printks to the code and saw that the signal does get sent
>> from iscsi_sw_tcp_conn_stop, but I didn't see that (rc == -EINTR || rc
>> == -EAGAIN) in  iscsi_sw_tcp_xmit (), even when I ran IO on that
>> session.
> Does r in iscsi_sw_tcp_xmit_segment == 0?

No, it is never zero.

> If not I think you need a diffferent patch. In one of the patch versions
> iscsi_sw_tcp_xmit_segment could return -ENODATA (this is when I had a
> check for suspend_tx in there). iscsi_sw_tcp_xmit did not check this and
> so I think  we can loop.
> Could you try the attached patch. It was made over open-iscsi.git for
> you. I dropped the suspend bit check in iscsi_sw_tcp_xmit_segment,
> because it is not needed. If we end up blocking the signal will wake us.

I ran it and got the same 100% cpu usage. Did you try to run it on
your machines with open-iscsi.git? Did you see a different behavior?


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