Re: [PATCH v3] qapi/qom: Memory backend property prealloc-threads doc fix

[Gavin Shan <gshan@redhat.com>]

Hi Zhenyu,

On 11/11/22 11:05 AM, Zhenyu Zhang wrote:
> Commit ffac16fab3 "hostmem: introduce "prealloc-threads" property"
> (v5.0.0) changed the default number of threads from number of CPUs
> to 1.  This was deemed a regression, and fixed in commit f8d426a685
> "hostmem: default the amount of prealloc-threads to smp-cpus".
> Except the documentation remained unchanged.  Update it now.
> 
> Signed-off-by: Zhenyu Zhang <zhenyzha@redhat.com>
> ---
> 
> v3: Covers historical descriptions                  (Markus)
> v2: The property is changed to smp-cpus since 5.0   (Phild)
> 
> ---
>   qapi/qom.json | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 

With the following comments addressed:

Reviewed-by: Gavin Shan <gshan@redhat.com>

---

Please consider amending the commit log to something like below.

The default "prealloc-threads" value is set to 1 when the property is
added by commit ffac16fab33b ("hostmem: introduce "prealloc-threads"
property") in v5.0.0. The default value is conflicting with the sugar
property as the value provided by the sugar property is number of CPUs.
The conflict has been fixed by commit f8d426a6852c ("hostmem: default
the amount of prealloc-threads to smp-cpus"). However, 'qapi/qom.json'
was missed to be updated accordingly in the commit.

Update 'qapi/qom.json' to reflect the change in commit f8d426a6852c.

Signed-off-by: Zhenyu Zhang <zhenyzha@redhat.com>

When a specific commit is mentioned in the commit log, we usually have
fixed format like below.

commit ffac16fab33b ("hostmem: introduce "prealloc-threads" property")
commit f8d426a6852c ("hostmem: default the amount of prealloc-threads to smp-cpus")

> diff --git a/qapi/qom.json b/qapi/qom.json
> index 30e76653ad..dfd89bc6d4 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: number of CPUs) (since 5.0)
>   #
>   # @prealloc-context: thread context to use for creation of preallocation threads
>   #                    (default: none) (since 7.2)
> 

The line seems exceeding 80 characters. It'd better to limit each line in 75 characters.
So you probably need:

     # @prealloc-threads: number of CPU threads to use for prealloc (default: number of CPUs)
     #                    (since 5.0)

Thanks,
Gavin