Re: [dpdk-dev] [v2 PATCH] usertools: show an error message if unable to reserve requested hugepages

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 7 Jan 2021 13:06:35 +0500
Sarosh Arif <sarosh.arif@emumba.com> wrote:

> On Thu, Dec 17, 2020 at 11:19 PM Stephen Hemminger
> <stephen@networkplumber.org> wrote:
> >
> > On Thu, 17 Dec 2020 16:16:16 +0500
> > Sarosh Arif <sarosh.arif@emumba.com> wrote:
> >  
> > > +    if get_hugepages(path) != pages:
> > > +        print("Unable to reserve required pages. The pages reserved are:")
> > > +        global SHOW_HUGEPAGES
> > > +        SHOW_HUGEPAGES = True  
> >
> >
> > Please don't add global's to this script.
> >
> > The script is close to being clean according to pylint, and globals
> > are considered bad style and shouldn't be used.
> >
> > I would just exit if huge pages could not be setup.  
> 
> How about if we just print a warning message such as "Unable to
> reserve required pages" before exiting, in case the pages are not
> reserved due to lack of space in RAM? Then leave it upon the user to
> query how many pages are actually reserved.
> >
> > The script should leave it up to the user to do another query about
> > status if they care about what the result is.  

Just call sys.exit with a message that is all that is needed.

Or maybe trapping other write errors to sysfs here. Probably the
kernel has already tried to report the error, but the try/except code
is not seeing it.