RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




> -----Original Message-----
> From: Olaf Hering [mailto:olaf@xxxxxxxxx]
> Sent: Monday, September 21, 2015 3:26 AM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Greg KH
> <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx;
> apw@xxxxxxxxxxxxx; vkuznets@xxxxxxxxxx; jasowang@xxxxxxxxxx
> Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state
> 
> On Sun, Sep 20, Greg KH wrote:
> 
> > Just use a lock, that's what it is there for.
> 
> How would that help? It might help because it enforces ordering. But
> that requires that all three utils get refactored to deal with the
> introduced locking. I will let KY comment on this.
> 
> The issue I see with fcopy is that after or while fcopy_respond_to_host
> runs an interrupt triggers which also calls into
> hv_fcopy_onchannelcallback.  It was most likely caused by a logic change
> in "recent" vmbus updates because this did not happen before. At least,
> the fcopy hang was not seen earler. Maybe the bug did just not trigger
> up to now for other reasons...

All util channels are bound to CPU 0. Just forcing all activity on CPU 0 may be the 
simplest solution here. Besides, these are not performance critical services anyway.

The problem you may have run into could be related to the fact that we could potentially
run the polling function on a CPU other than CPU 0.

Regards,

K. Y
> 
> Olaf
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel



[Index of Archives]     [Linux Driver Backports]     [DMA Engine]     [Linux GPIO]     [Linux SPI]     [Video for Linux]     [Linux USB Devel]     [Linux Coverity]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]
  Powered by Linux