Re: [PATCH] tools: fix oom setting of xenstored

[Juergen Gross <jgross@xxxxxxxx>]

On 19.10.21 08:54, Jan Beulich wrote:
> On 19.10.2021 06:41, Juergen Gross wrote:
> > --- a/tools/hotplug/Linux/launch-xenstore.in
> > +++ b/tools/hotplug/Linux/launch-xenstore.in
> > @@ -60,7 +60,7 @@ test -f @CONFIG_DIR@/@CONFIG_LEAF_DIR@/xencommons && . 
> > @CONFIG_DIR@/@CONFIG_LEAF
> >                 echo "No xenstored found"
> >                 exit 1
> >         }
> > -       [ -z "$XENSTORED_OOM_MEM_THRESHOLD" ] || XENSTORED_OOM_MEM_THRESHOLD=50
> > +       [ -z "$XENSTORED_OOM_MEM_THRESHOLD" ] && XENSTORED_OOM_MEM_THRESHOLD=50
> Is resilience against "set -e" being in effect of interest? If so I
> think this would want to be
I don't think set -e would have a negative effect on above line. The
bash man-page tells me that:

  The shell does not exit if the command that fails is part of the
  command list immediately following a while or until keyword, part of
  the test following the if, ...

And I believe that "[ ... ]" is treated like an "if". A short test
showed that bash indeed does not exit in this case:

  ( set -e; [ -z "" ] && xx=okay; echo $xx; )

This will print "okay", so bash didn't exit.

>         [ -n "$XENSTORED_OOM_MEM_THRESHOLD" ] || XENSTORED_OOM_MEM_THRESHOLD=50
>
> >         XS_OOM_SCORE=-$(($XENSTORED_OOM_MEM_THRESHOLD * 10))
> Alternatively, how about dropping the line above and using
>
>         XS_OOM_SCORE=-$((${XENSTORED_OOM_MEM_THRESHOLD:-50} * 10))
>
> here?
This would be an option, yes.

Unless a maintainer wants me to send another patch with this change I'll
keep it as it is now.


Juergen

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