Re: Enormous size of libvirt libxl-driver.log with Xen 4.2 and 4.3

[Ian Campbell <ian.campbell@citrix.com>]

On Mon, 2015-08-03 at 11:47 +0100, Ian Campbell wrote:
> After the initial expected logging the file is simply full of:
> 
> 2015-08-02 19:12:12 UTC libxl: debug: libxl.c:1004:domain_death_xswatch_callback: [evg=0x7f3cc44fa3f0:3] from domid=0 nentries=1 rc=1
> 2015-08-02 19:12:12 UTC libxl: debug: libxl.c:1015:domain_death_xswatch_callback: [evg=0x7f3cc44fa3f0:3]   got=domaininfos[0] got->domain=0
> 2015-08-02 19:12:12 UTC libxl: debug: libxl.c:1015:domain_death_xswatch_callback: [evg=0x7f3cc44fa3f0:3]   got=domaininfos[1] got->domain=-1
> 2015-08-02 19:12:12 UTC libxl: debug: libxl.c:1023:domain_death_xswatch_callback:  got==gotend
> 
> Repeated at around 51KHz.

This sounds a lot like 4783c99aab8 (see below for full log message), which
perhaps ought to be backported to the effected branches, i.e. 4.2 and 4.3. 

Looks like it was backported to 4.5 (as 0b19348f3cd1) and 4.4 (as
13623d5d8e85) already.

Ian?

Ian.


commit 4783c99aab866f470bd59368cfbf5ad5f677b0ec
Author: Ian Jackson <Ian.Jackson@eu.citrix.com>
Date:   Tue Mar 17 09:30:57 2015 -0600

    libxl: In domain death search, start search at first domid we want
    
    From: Ian Jackson <Ian.Jackson@eu.citrix.com>
    
    When domain_death_xswatch_callback needed a further call to
    xc_domain_getinfolist it would restart it with the last domain it
    found rather than the first one it wants.
    
    If it only wants one it will also only ask for one domain.  The result
    would then be that it gets the previous domain again (ie, the previous
    one to the one it wants), which still doesn't reveal the answer to the
    question, and it would therefore loop again.
    
    It's completely unclear to me why I thought it was a good idea to
    start the xc_domain_getinfolist with the last domain previously found
    rather than the first one left un-confirmed.  The code has been that
    way since it was introduced.
    
    Instead, start each xc_domain_getinfolist at the next domain whose
    status we need to check.
    
    We also need to move the test for !evg into the loop, we now need evg
    to compute the arguments to getinfolist.
    
    Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
    Reported-by: Jim Fehlig <jfehlig@suse.com>
    Reviewed-by: Jim Fehlig <jfehlig@suse.com>
    Tested-by: Jim Fehlig <jfehlig@suse.com>
    Acked-by: Wei Liu <wei.liu2@citrix.com>
    Acked-by: Ian Campbell <ian.campbell@citrix.com>