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Re: [PATCH v11 11/14] machine: Make smp_parse generic enough for all arc
Re: [PATCH v11 11/14] machine: Make smp_parse generic enough for all arches
Tue, 28 Sep 2021 20:53:32 +0800
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On 2021/9/28 20:25, Markus Armbruster wrote:
Philippe Mathieu-Daudé <firstname.lastname@example.org> writes:
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 <email@example.com>
Suggested-by: Daniel P. Berrange <firstname.lastname@example.org>
Signed-off-by: Yanan Wang <email@example.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
Can we have it return a boolean instead?
Yes, please. From error.h's big comment:
* = Rules =
* - Whenever practical, also return a value that indicates success /
* failure. This can make the error checking more concise, and can
* avoid useless error object creation and destruction. Note that
* we still have many functions returning void. We recommend
* • bool-valued functions return true on success / false on failure,
* • pointer-valued functions return non-null / null pointer, and
* • integer-valued functions return non-negative / negative.
Ok. I will add an extra patch to this series to do the change and respin.
In practice the boolean return value will also make a smp parsing unit
test more concise. (I'm planning to introduce one test).
[PATCH v11 10/14] machine: Tweak the order of topology members in struct CpuTopology, Yanan Wang, 2021/09/27
[PATCH v11 13/14] machine: Move smp_prefer_sockets to struct SMPCompatProps, Yanan Wang, 2021/09/27
[PATCH v11 12/14] machine: Remove smp_parse callback from MachineClass, Yanan Wang, 2021/09/27
[PATCH v11 14/14] machine: Put all sanity-check in the generic SMP parser, Yanan Wang, 2021/09/27
- [PATCH v11 09/14] machine: Use ms instead of global current_machine in sanity-check, (continued)