Re: [PATCH v5 2/2] tools/xenstore: set open file descriptor limit for xenstored

[Ian Jackson <iwj@xenproject.org>]

Juergen Gross writes ("Re: [PATCH v5 2/2] tools/xenstore: set open file descriptor limit for xenstored"):
> Hmm, maybe I should just use:
> 
> prlimit --nofile=$XENSTORED_MAX_OPEN_FDS \
>     $XENSTORED --pid-file @XEN_RUN_DIR@/xenstored.pid $XENSTORED_ARGS

I guess that would probably work (although it involves another
exec) but I don't understand what's wrong with ulimit, which is a
shell builtin.

I think this script has to run only on Linux and all reasonable Linux
/bin/sh have `ulimit`.  (I have checked dash and bash.)

So I think just

  ulimit -n $XENSTORED_MAX_OPEN_FDS

  $XENSTORED --pid-file @XEN_RUN_DIR@/xenstored.pid $XENSTORED_ARGS

will DTRT.  You could also do this

  ulimit -n $XENSTORED_MAX_OPEN_FDS || true

which will arrange that if, somehow, this fails, the system is likely
to continue to mostly-work despite the error.  Whether that would be
desirable is a matter of taste I think.

(I have RTFM again, and setting -H and -S separately is not needed;
omitting -H or -S means to set both.)

Ian.