Re: port-xen/50659: Xen4.5 crash with vnds

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR kern/50659; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: Christoph Badura <bad%bsd.de@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        netbsd-bugs%netbsd.org@localhost, sebastian%xenoserver.net@localhost
Subject: Re: port-xen/50659: Xen4.5 crash with vnds
Date: Thu, 24 Mar 2016 22:34:31 +0100

 On Thu, Mar 24, 2016 at 10:22:36PM +0100, Christoph Badura wrote:
 > On Thu, Mar 24, 2016 at 09:38:06PM +0100, Manuel Bouyer wrote:
 > > > If you looks at the linux hotplug scripts, they do their own serialization
 > > > as appropriate.  "grep -r _lock hotplug/Linux".
 > > 
 > > I tried to do something with shlock(1) but it doens't work, it's too
 > > slow and xl times out. 
 > > Maybe flock would work but older NetBSD don't have it ...
 > 
 > I noticed that you said before that shlock was too slow.  I'm surprised.
 > The linux claim_lock functions calls out to perl...
 
 the problem is that shlock can't wait on the lock by itself.
 If it fail you have to retry, and in sh I didn't find a way to sleep
 for less than 1s before retry (or you could busy-wait but I'm not sure
 it's better).
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --