[PATCH] gnttab: silence table expansion message

[PATCH] gnttab: silence table expansion message

[Jan Beulich]

This currently shows up for basically every domain, when originally it
was logged only when going beyond the default table size. Restore that
behavior.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -1764,9 +1764,10 @@ gnttab_grow_table(struct domain *d, unsi
         req_nr_frames = INITIAL_NR_GRANT_FRAMES;
     ASSERT(req_nr_frames <= gt->max_grant_frames);
 
-    gdprintk(XENLOG_INFO,
-            "Expanding d%d grant table from %u to %u frames\n",
-            d->domain_id, nr_grant_frames(gt), req_nr_frames);
+    if ( req_nr_frames > INITIAL_NR_GRANT_FRAMES )
+        gdprintk(XENLOG_INFO,
+                 "Expanding d%d grant table from %u to %u frames\n",
+                 d->domain_id, nr_grant_frames(gt), req_nr_frames);
 
     /* Active */
     for ( i = nr_active_grant_frames(gt);



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Re: [PATCH] gnttab: silence table expansion message

[Wei Liu]

On Tue, Jun 26, 2018 at 01:22:01AM -0600, Jan Beulich wrote:
> This currently shows up for basically every domain, when originally it
> was logged only when going beyond the default table size. Restore that
> behavior.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

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Re: [PATCH] gnttab: silence table expansion message

[Andrew Cooper]

On 26/06/18 08:22, Jan Beulich wrote:
> This currently shows up for basically every domain, when originally it
> was logged only when going beyond the default table size. Restore that
> behavior.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> --- a/xen/common/grant_table.c
> +++ b/xen/common/grant_table.c
> @@ -1764,9 +1764,10 @@ gnttab_grow_table(struct domain *d, unsi
>          req_nr_frames = INITIAL_NR_GRANT_FRAMES;
>      ASSERT(req_nr_frames <= gt->max_grant_frames);
>  
> -    gdprintk(XENLOG_INFO,
> -            "Expanding d%d grant table from %u to %u frames\n",
> -            d->domain_id, nr_grant_frames(gt), req_nr_frames);
> +    if ( req_nr_frames > INITIAL_NR_GRANT_FRAMES )
> +        gdprintk(XENLOG_INFO,
> +                 "Expanding d%d grant table from %u to %u frames\n",
> +                 d->domain_id, nr_grant_frames(gt), req_nr_frames);

This has been on my todo list for a while, but I'd go one stage further
and delete it fully.

Domains either never trigger it, or expand to max.  It doesn't provide
any useful information at all.

~Andrew

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Re: [PATCH] gnttab: silence table expansion message

[Paul Durrant]

> -----Original Message-----
> From: Xen-devel [mailto:xen-devel-bounces@lists.xenproject.org] On Behalf
> Of Andrew Cooper
> Sent: 26 June 2018 12:15
> To: Jan Beulich <JBeulich@suse.com>; xen-devel <xen-
> devel@lists.xenproject.org>
> Cc: Stefano Stabellini <sstabellini@kernel.org>; Wei Liu
> <wei.liu2@citrix.com>; George Dunlap <George.Dunlap@citrix.com>; Tim
> (Xen.org) <tim@xen.org>; Ian Jackson <Ian.Jackson@citrix.com>; Julien Grall
> <julien.grall@arm.com>
> Subject: Re: [Xen-devel] [PATCH] gnttab: silence table expansion message
> 
> On 26/06/18 08:22, Jan Beulich wrote:
> > This currently shows up for basically every domain, when originally it
> > was logged only when going beyond the default table size. Restore that
> > behavior.
> >
> > Signed-off-by: Jan Beulich <jbeulich@suse.com>
> >
> > --- a/xen/common/grant_table.c
> > +++ b/xen/common/grant_table.c
> > @@ -1764,9 +1764,10 @@ gnttab_grow_table(struct domain *d, unsi
> >          req_nr_frames = INITIAL_NR_GRANT_FRAMES;
> >      ASSERT(req_nr_frames <= gt->max_grant_frames);
> >
> > -    gdprintk(XENLOG_INFO,
> > -            "Expanding d%d grant table from %u to %u frames\n",
> > -            d->domain_id, nr_grant_frames(gt), req_nr_frames);
> > +    if ( req_nr_frames > INITIAL_NR_GRANT_FRAMES )
> > +        gdprintk(XENLOG_INFO,
> > +                 "Expanding d%d grant table from %u to %u frames\n",
> > +                 d->domain_id, nr_grant_frames(gt), req_nr_frames);
> 
> This has been on my todo list for a while, but I'd go one stage further
> and delete it fully.
> 
> Domains either never trigger it, or expand to max.  It doesn't provide
> any useful information at all.

That's not entirely true. Windows PV drivers expand the grant table on demand, not straight to max. Having said that, they do their own logging so the extra noise from Xen is not useful.

  Paul

> 
> ~Andrew
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xenproject.org
> https://lists.xenproject.org/mailman/listinfo/xen-devel
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Re: [PATCH] gnttab: silence table expansion message

[Jan Beulich]

>>> On 26.06.18 at 13:14, <andrew.cooper3@citrix.com> wrote:
> On 26/06/18 08:22, Jan Beulich wrote:
>> This currently shows up for basically every domain, when originally it
>> was logged only when going beyond the default table size. Restore that
>> behavior.
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>
>> --- a/xen/common/grant_table.c
>> +++ b/xen/common/grant_table.c
>> @@ -1764,9 +1764,10 @@ gnttab_grow_table(struct domain *d, unsi
>>          req_nr_frames = INITIAL_NR_GRANT_FRAMES;
>>      ASSERT(req_nr_frames <= gt->max_grant_frames);
>>  
>> -    gdprintk(XENLOG_INFO,
>> -            "Expanding d%d grant table from %u to %u frames\n",
>> -            d->domain_id, nr_grant_frames(gt), req_nr_frames);
>> +    if ( req_nr_frames > INITIAL_NR_GRANT_FRAMES )
>> +        gdprintk(XENLOG_INFO,
>> +                 "Expanding d%d grant table from %u to %u frames\n",
>> +                 d->domain_id, nr_grant_frames(gt), req_nr_frames);
> 
> This has been on my todo list for a while, but I'd go one stage further
> and delete it fully.
> 
> Domains either never trigger it, or expand to max.  It doesn't provide
> any useful information at all.

I disagree - domains don't normally use all or nothing of grant tables.
And this (being a debug message only) may be a useful hint if a
domain not expected to use all of its grant table suddenly grows its
size significantly.

My main goal here really is to get rid of the 0 -> 1 transition message
(when starting a guest).

Jan



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