Re: [PATCH] 9pfs: log warning if msize <= 8192

[Greg Kurz]

On Wed, 02 Sep 2020 18:03:12 +0200
Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:

> On Mittwoch, 2. September 2020 16:10:35 CEST Daniel P. Berrangé wrote:
> > > Yeah, I know, but the problem is I don't see how I would squeeze the
> > > relevant information into only one log message; and even "what's a good
> > > starting point" is already questionable.
> > > 
> > > For that reason my plan was:
> > >   - logging this warning
> > >   
> > >   - describing the 'msize' issue in detail on the QEMU wiki (what's the
> > >   
> > >     point, how would you benchmark it)
> > > 
> > > So my idea was: user sees the message, "what is 'msize?'" -> Google "msize
> > > qemu" -> click 'QEMU wiki' -> read all the details.
> > > 
> > > But how about this: I put a QEMU wiki link directly into the log message?
> > 
> > Rather than that, how about putting it in the QEMU man page, and then
> > just add  "See 'man 1 qemu' for further guidance".
> 
> Well, I can do that of course. But somehow I fear users get lost by just 
> pointing them to "man 1 qemu" in the log message. It already starts that e.g. 
> on Debian there is no "man qemu", it is "man qemu-system" there instead. Next 
> issue is that qemu man page is currently not structured in a way that would 
> allow me to directly point them to the relevant man heading like:
> 
>       man --pager='less -p ^9P-msize' qemu
> 
> So they would need to scroll their way through the entire man page by 
> themselfes and find confusing sections like "-fsdev -device virtio-9p-pci" vs.
> "-virtfs", etc. I can imagine some people will struggle with that.
> 
> With a link like "https://wiki.qemu.org/Documentation/9psetup#msize"; the 
> thing 
> would be crystal clear within seconds.
> 
> Just my opinion. Greg?
> 

Fine by me for this patch.

For a longer term, maybe we should find a way to advertise some hint
for msize to the guest... Not sure how to do that though.

Cheers,

--
Greg

> Best regards,
> Christian Schoenebeck
> 
>