From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Andrew Jones <drjones@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
Thomas Huth <thuth@redhat.com>,
Eduardo Habkost <ehabkost@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
wanghaibin.wang@huawei.com,
Richard Henderson <richard.henderson@linaro.org>,
qemu-devel@nongnu.org, Greg Kurz <groug@kaod.org>,
Yanan Wang <wangyanan55@huawei.com>,
yuzenghui@huawei.com, Igor Mammedov <imammedo@redhat.com>,
Halil Pasic <pasic@linux.ibm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH for-6.2 v2 02/11] machine: Make smp_parse generic enough for all arches
Date: Mon, 19 Jul 2021 17:50:23 +0100 [thread overview]
Message-ID: <YPWtTxMISucwEjxj@redhat.com> (raw)
In-Reply-To: <20210719164815.bzfnrk6fzhfj5quj@gator>
On Mon, Jul 19, 2021 at 06:48:15PM +0200, Andrew Jones wrote:
> On Mon, Jul 19, 2021 at 05:36:39PM +0100, Daniel P. Berrangé wrote:
> > On Mon, Jul 19, 2021 at 06:28:46PM +0200, Andrew Jones wrote:
> > > On Mon, Jul 19, 2021 at 11:20:34AM +0800, Yanan Wang wrote:
> > > > Currently the only difference between smp_parse and pc_smp_parse
> > > > is the support of multi-dies and the related error reporting code.
> > > > With an arch compat variable "bool smp_dies_supported", we can
> > > > easily 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.
> > > >
> > > > No functional change intended.
> > > >
> > > > Suggested-by: Andrew Jones <drjones@redhat.com>
> > > > Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> > > > ---
> > > > hw/core/machine.c | 28 ++++++++++-------
> > > > hw/i386/pc.c | 76 +--------------------------------------------
> > > > include/hw/boards.h | 1 +
> > > > 3 files changed, 19 insertions(+), 86 deletions(-)
> > > >
> > > > diff --git a/hw/core/machine.c b/hw/core/machine.c
> > > > index d73daa10f4..ed6712e964 100644
> > > > --- a/hw/core/machine.c
> > > > +++ b/hw/core/machine.c
> > > > @@ -743,6 +743,7 @@ void machine_set_cpu_numa_node(MachineState *machine,
> > > >
> > > > static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
> > > > {
> > > > + MachineClass *mc = MACHINE_GET_CLASS(ms);
> > > > unsigned cpus = config->has_cpus ? config->cpus : 0;
> > > > unsigned sockets = config->has_sockets ? config->sockets : 0;
> > > > unsigned dies = config->has_dies ? config->dies : 1;
> > > > @@ -761,7 +762,7 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
> > > > return;
> > > > }
> > > >
> > > > - if (dies > 1) {
> > > > + if (!mc->smp_dies_supported && dies > 1) {
> > >
> > > Won't this allow a user on an arch with !mc->smp_dies_supported to specify
> > > dies=1?
> >
> > Conceptually that is fine. Before the introduction of CPU sockets
> > with 2+ dies, you can credibly say that all sockets had 1 die, so
> > it is nreasonable for users to say -smp ....,dies=1,....
> >
> > libvirt will unconditionally set dies=1 for all QEMU targets if
> > the user didn't specify an explicit dies value
> >
> > > To not allow that, can we do
> > >
> > > if (!mc->smp_dies_supported && config->has_dies)
> > >
> > > instead?
> >
> > I don't see that this is benefitting apps/users.
>
> Other than maintaining consistency; erroring with "we don't support dies"
> for 2+, but not for 1, is inconsistent, then I agree there isn't much
> reason to disallow it, since we'll be using the value of 1 anyway
> internally. I don't really have a strong preference here, so I'm fine with
> allowing dies=1.
How about we tweak the error message from
"dies not supported by this machine's CPU topology"
to
"multiple dies not supported by this machine's CPU topology"
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
next prev parent reply other threads:[~2021-07-19 16:51 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 3:20 [PATCH for-6.2 v2 00/11] machine: smp parsing fixes and improvement Yanan Wang
2021-07-19 3:20 ` [PATCH for-6.2 v2 01/11] machine: Disallow specifying topology parameters as zero Yanan Wang
2021-07-19 16:11 ` Andrew Jones
2021-07-21 12:34 ` wangyanan (Y)
2021-07-19 16:46 ` Daniel P. Berrangé
2021-07-21 12:35 ` wangyanan (Y)
2021-07-19 3:20 ` [PATCH for-6.2 v2 02/11] machine: Make smp_parse generic enough for all arches Yanan Wang
2021-07-19 16:28 ` Andrew Jones
2021-07-19 16:36 ` Daniel P. Berrangé
2021-07-19 16:48 ` Andrew Jones
2021-07-19 16:50 ` Daniel P. Berrangé [this message]
2021-07-19 16:53 ` Daniel P. Berrangé
2021-07-22 7:18 ` wangyanan (Y)
2021-07-20 6:57 ` Cornelia Huck
2021-07-22 7:12 ` wangyanan (Y)
2021-07-19 3:20 ` [PATCH for-6.2 v2 03/11] machine: Uniformly use maxcpus to calculate the omitted parameters Yanan Wang
2021-07-19 16:36 ` Andrew Jones
2021-07-22 3:00 ` wangyanan (Y)
2021-07-19 3:20 ` [PATCH for-6.2 v2 04/11] machine: Use the computed parameters to calculate omitted cpus Yanan Wang
2021-07-19 16:42 ` Andrew Jones
2021-07-22 4:42 ` wangyanan (Y)
2021-07-22 12:27 ` Andrew Jones
2021-07-22 14:59 ` wangyanan (Y)
2021-07-22 15:05 ` Andrew Jones
2021-07-22 15:45 ` wangyanan (Y)
2021-07-19 3:20 ` [PATCH for-6.2 v2 05/11] machine: Improve the error reporting of smp parsing Yanan Wang
2021-07-19 16:53 ` Andrew Jones
2021-07-22 8:10 ` wangyanan (Y)
2021-07-22 12:47 ` Andrew Jones
2021-07-19 3:20 ` [PATCH for-6.2 v2 06/11] hw: Add compat machines for 6.2 Yanan Wang
2021-07-19 3:38 ` David Gibson
2021-07-19 17:00 ` Andrew Jones
2021-07-19 17:03 ` Cornelia Huck
2021-07-19 23:45 ` Pankaj Gupta
2021-07-19 3:20 ` [PATCH for-6.2 v2 07/11] machine: Prefer cores over sockets in smp parsing since 6.2 Yanan Wang
2021-07-19 3:40 ` David Gibson
2021-07-22 5:22 ` wangyanan (Y)
2021-07-19 17:13 ` Andrew Jones
2021-07-22 5:32 ` wangyanan (Y)
2021-07-19 3:20 ` [PATCH for-6.2 v2 08/11] machine: Use ms instead of global current_machine in sanity-check Yanan Wang
2021-07-19 17:14 ` Andrew Jones
2021-07-19 3:20 ` [PATCH for-6.2 v2 09/11] machine: Tweak the order of topology members in struct CpuTopology Yanan Wang
2021-07-19 3:20 ` [PATCH for-6.2 v2 10/11] machine: Split out the smp parsing code Yanan Wang
2021-07-19 17:20 ` Andrew Jones
2021-07-22 6:24 ` wangyanan (Y)
2021-07-22 13:07 ` Andrew Jones
2021-07-22 14:29 ` wangyanan (Y)
2021-07-19 3:20 ` [PATCH for-6.2 v2 11/11] tests/unit: Add a unit test for smp parsing Yanan Wang
2021-07-19 18:57 ` Andrew Jones
2021-07-22 6:15 ` wangyanan (Y)
2021-07-22 13:12 ` Andrew Jones
2021-07-22 14:18 ` wangyanan (Y)
2021-07-19 16:57 ` [PATCH for-6.2 v2 00/11] machine: smp parsing fixes and improvement Cornelia Huck
2021-07-21 12:38 ` wangyanan (Y)
2021-07-21 13:52 ` Pankaj Gupta
2021-07-22 2:22 ` wangyanan (Y)
2021-07-22 7:51 ` Pierre Morel
2021-07-22 8:32 ` wangyanan (Y)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YPWtTxMISucwEjxj@redhat.com \
--to=berrange@redhat.com \
--cc=david@gibson.dropbear.id.au \
--cc=drjones@redhat.com \
--cc=ehabkost@redhat.com \
--cc=groug@kaod.org \
--cc=imammedo@redhat.com \
--cc=mst@redhat.com \
--cc=pasic@linux.ibm.com \
--cc=pbonzini@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=richard.henderson@linaro.org \
--cc=thuth@redhat.com \
--cc=wanghaibin.wang@huawei.com \
--cc=wangyanan55@huawei.com \
--cc=yuzenghui@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).