Re: [PATCH V2 1/3] vl: Allow multiple -overcommit commands

[Zhao Liu <zhao1.liu@intel.com>]

On Mon, May 27, 2024 at 07:19:56AM +0200, Thomas Huth wrote:
> Date: Mon, 27 May 2024 07:19:56 +0200
> From: Thomas Huth <thuth@redhat.com>
> Subject: Re: [PATCH V2 1/3] vl: Allow multiple -overcommit commands
> 
> On 24/05/2024 22.00, Zide Chen wrote:
> > Both cpu-pm and mem-lock are related to system resource overcommit, but
> > they are separate from each other, in terms of how they are realized,
> > and of course, they are applied to different system resources.
> > 
> > It's tempting to use separate command lines to specify their behavior.
> > e.g., in the following example, the cpu-pm command is quietly
> > overwritten, and it's not easy to notice it without careful inspection.
> > 
> >    --overcommit mem-lock=on
> >    --overcommit cpu-pm=on
> > 
> > Fixes: c8c9dc42b7ca ("Remove the deprecated -realtime option")
> > Suggested-by: Thomas Huth <thuth@redhat.com>
> > Signed-off-by: Zide Chen <zide.chen@intel.com>
> > ---
> > 
> > v2:
> > 
> > Thanks to Thomas' suggestion, changed to this better approach, which
> > is more generic and can handle situations like: "enabled the option in
> > the config file, and now you'd like to disable it on the command line
> > again".
> > 
> >   system/vl.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/system/vl.c b/system/vl.c
> > index a3eede5fa5b8..dfa6cdd9283b 100644
> > --- a/system/vl.c
> > +++ b/system/vl.c
> > @@ -3545,8 +3545,8 @@ void qemu_init(int argc, char **argv)
> >                   if (!opts) {
> >                       exit(1);
> >                   }
> > -                enable_mlock = qemu_opt_get_bool(opts, "mem-lock", false);
> > -                enable_cpu_pm = qemu_opt_get_bool(opts, "cpu-pm", false);
> > +                enable_mlock = qemu_opt_get_bool(opts, "mem-lock", enable_mlock);
> > +                enable_cpu_pm = qemu_opt_get_bool(opts, "cpu-pm", enable_cpu_pm);
> >                   break;
> >               case QEMU_OPTION_compat:
> >                   {
> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> 

Hi Thomas,

BTW, do you think it's a good idea to define the overcommit via QAPI way
(defined in a json file)? ;-)

My rough understanding is that all APIs are better to be defined via
QAPI to go JSON compatible.