Re: [PATCH v11 11/14] machine: Make smp_parse generic enough for all arches

[wangyanan (Y)]

On 2021/9/28 18:58, Daniel P. Berrangé wrote:
> On Tue, Sep 28, 2021 at 12:57:21PM +0200, Philippe Mathieu-Daudé wrote:
> > On 9/28/21 05:57, Yanan Wang wrote:
> > > Currently the only difference between smp_parse and pc_smp_parse
> > > is the support of dies parameter and the related error reporting.
> > > With some arch compat variables like "bool dies_supported", we can
> > > make smp_parse generic enough for all arches and the PC specific
> > > one can be removed.
> > >
> > > Making smp_parse() generic enough can reduce code duplication and
> > > ease the code maintenance, and also allows extending the topology
> > > with more arch specific members (e.g., clusters) in the future.
> > >
> > > Suggested-by: Andrew Jones <drjones@redhat.com>
> > > Suggested-by: Daniel P. Berrange <berrange@redhat.com>
> > > Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> > > ---
> > >   hw/core/machine.c   | 91 +++++++++++++++++++++++++++++++++++----------
> > >   hw/i386/pc.c        | 84 +----------------------------------------
> > >   include/hw/boards.h |  9 +++++
> > >   3 files changed, 81 insertions(+), 103 deletions(-)
> > > +/*
> > > + * smp_parse - Generic function used to parse the given SMP configuration
> > > + *
> > > + * Any missing parameter in "cpus/maxcpus/sockets/cores/threads" will be
> > > + * automatically computed based on the provided ones.
> > > + *
> > > + * In the calculation of omitted sockets/cores/threads: we prefer sockets
> > > + * over cores over threads before 6.2, while preferring cores over sockets
> > > + * over threads since 6.2.
> > > + *
> > > + * In the calculation of cpus/maxcpus: When both maxcpus and cpus are omitted,
> > > + * maxcpus will be computed from the given parameters and cpus will be set
> > > + * equal to maxcpus. When only one of maxcpus and cpus is given then the
> > > + * omitted one will be set to its given counterpart's value. Both maxcpus and
> > > + * cpus may be specified, but maxcpus must be equal to or greater than cpus.
> > > + *
> > > + * For compatibility, apart from the parameters that will be computed, newly
> > > + * introduced topology members which are likely to be target specific should
> > > + * be directly set as 1 if they are omitted (e.g. dies for PC since 4.1).
> > > + */
> > >   static void smp_parse(MachineState *ms, SMPConfiguration *config, Error 
> > > **errp)
> > Can we have it return a boolean instead?
> That's unrelated to this change, so ought to be a separate commit if
> done.
I agree. I vaguely remember that there was a discussion about this before
with Paolo. But anyway, I think the suggested change can be in a separate
commit if necessary. :)

Thanks,
Yanan