Re: [PATCH] qom.json: default the prealloc-threads to smp-cpus

[Igor Mammedov]

On Fri, 04 Nov 2022 05:53:02 +0100
Markus Armbruster <armbru@redhat.com> wrote:

> Philippe Mathieu-Daudé <philmd@linaro.org> writes:
> 
> > On 3/11/22 11:47, Zhenyu Zhang wrote:  
> >> Since the amount of prealloc-threads to smp-cpus is
> >> defaulted in hostmem, so sync this information.  
> 
> Has this always defaulted to smp-cpus, or did this change along the way?
yes and no
(originally value was 1 with vl.c fixing it up to smp-cpus when
legacy -mem-prealloc was used)
  ffac16fab33bb hostmem: introduce "prealloc-threads" property
however later on
  2a4e02d104b1 hostmem: set default prealloc_threads to valid value
hack was merged (sigh),
brought back direct dependency on machine->smp.cpus to memory
allocation and that flipped default to number of smp-cpus.

> >> Signed-off-by: Zhenyu Zhang <zhenyzha@redhat.com>
> >> ---
> >>   qapi/qom.json | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >> diff --git a/qapi/qom.json b/qapi/qom.json
> >> index 87fcad2423..ac4cd213a7 100644
> >> --- a/qapi/qom.json
> >> +++ b/qapi/qom.json
> >> @@ -576,7 +576,7 @@
> >>   #
> >>   # @prealloc: if true, preallocate memory (default: false)
> >>   #
> >> -# @prealloc-threads: number of CPU threads to use for prealloc (default: 
> >> 1)
> >> +# @prealloc-threads: number of CPU threads to use for prealloc (default: 
> >> smp-cpus) (since 7.1)  
> >
> > The property is present since 5.0. Shouldn't this be "(default: smp-cpus) 
> > (since 5.0)"?  
> 
> Yes.
> 
> >>   #
> >>   # @prealloc-context: thread context to use for creation of preallocation 
> >> threads
> >>   #                    (default: none) (since 7.2)  
>