[Pacemaker] SysInfo_mem_units()

[Simon Horman]

On Wed, Jul 07, 2010 at 08:27:17AM +0200, Andrew Beekhof wrote:
> On Wed, Jul 7, 2010 at 6:17 AM, Simon Horman <horms at verge.net.au> wrote:
> > Hi,
> >
> > I am currently pondering the SysInfo_mem_units() function
> > of sources/SysInfo (with a view to turning it into awk to
> > avoid bashisms[1]).
> >
> > Basically the function seems to look at the unit of the input,
> > leave it as if if the unit is G, divide it by 1024 if its M[bB]?
> > or divide it by 1024^2 if the unit is k[B]?. It then does some rounding.
> >
> > On the unit handling side of things I am puzzled by the following code,
> > particularly the inner if [ $mem != ${mem/./} ] portion. It seems to
> > handle the x.yG case. But the logic seems to lead to the following result:
> >
> > xG => x
> > x.yG => 1024x + w*y
> >
> > Surely the latter should be x.yG => x + (w*y/1024).
> > Also, surely this logic also applies equally to other units.

Can you comment on this?

> >
> >    if [ ${mem:$memlen:1} = "G" ]; then
> >        mem="${mem:0:$memlen}"
> >        if [ $mem != ${mem/./} ]; then
> >            mem_before=${mem/.*/}
> >            mem_after=${mem/*./}
> >            mem=$[mem_before*1024]
> >            if [ ${#mem_after} = 0 ]; then
> >                :
> >            elif [ ${#mem_after} = 1 ]; then
> >                mem=$[mem+100*$mem_after]
> >            elif [ ${#mem_after} = 2 ]; then
> >                mem=$[mem+10*$mem_after]
> >            elif [ ${#mem_after} = 3 ]; then
> >                mem=$[mem+$mem_after]
> >            else
> >                mem_after=${mem_after:0:3}
> >                mem=$[mem+$mem_after]
> >            fi
> >        fi
> >    elif [ ${mem:$memlen:1} = "M" ]; then
> >
> >
> > [1] I also struggle to care about this bashism crusade. But its
> 
> yeah, me too. but it also means that when people send patches I don't
> care enough to argue against them.
> 
> >    something that Debian has decided matters, so I'm doing
> >    this with my debian-ha-maintainer member hat on.
> >
> >    The following hunk illustrates how I think SysInfo_hdd_units() can
> >    be handled. The awk version seems rather nicer or at least rather
> >    shorter than the original.
> 
> agreed.  do you have a tree i can pull this from?
> that or can you resend as a hg export so you can get the proper attribution :-)

I was planning to send it as part of a larger patch (a bit later).
But I can send it by itself (sooner) if you prefer.

> > Index: stable-1.0.wip/extra/resources/SysInfo
> > ===================================================================
> > --- stable-1.0.wip.orig/extra/resources/SysInfo 2010-07-07 12:59:31.000000000 +0900
> > +++ stable-1.0.wip/extra/resources/SysInfo      2010-07-07 13:15:32.000000000 +0900
> > @@ -251,33 +247,13 @@ SysInfo_mem_units() {
> >  }
> >
> >  SysInfo_hdd_units() {
> > -    disk=$1
> > -    disklen=`expr ${#disk} - 1`
> > -    disklen_alt=`expr ${#disk} - 2`
> > -    if [ ${disk:$disklen:1} = "G" ]; then
> > -       disk="${disk:0:$disklen}"
> > -    elif [ ${disk:$disklen:1} = "M" ]; then
> > -       disk="${disk:0:$disklen}"
> > -       disk=${disk/.*/}
> > -       disk=`expr $disk / 1024`
> > -    elif [ ${disk:$disklen:1} = "k" ]; then
> > -       disk="${disk:0:$disklen}"
> > -       disk=${disk/.*/}
> > -       disk=`expr $disk / 1048576`
> > -    elif [ ${disk:$disklen_alt:2} = "kB" ]; then
> > -       disk="${disk:0:$disklen_alt}"
> > -       disk=${disk/.*/}
> > -       disk=`expr $disk / 1048576`
> > -    elif [ ${disk:$disklen_alt:2} = "Mb" ]; then
> > -       disk="${disk:0:$disklen_alt}"
> > -       disk=${disk/.*/}
> > -       disk=`expr $disk / 1024`
> > -    elif [ ${disk:$disklen_alt:2} = "MB" ]; then
> > -       disk="${disk:0:$disklen_alt}"
> > -       disk=${disk/.*/}
> > -       disk=`expr $disk / 1024`
> > -    fi
> > -    echo $disk
> > +    # Size in gigabytes
> > +    echo $1 | awk '{ split($0, a, /[^0-9]/);
> > +                    n=a[1];
> > +                    sub(n, "");
> > +                    if (/^M[Bb]?$/) { n /= 1024 };
> > +                    if (/^kB?/) { n /= 1048576 };
> > +                    print n }'
> >  }
> >
> >  SysInfo_usage() {
> >
> > _______________________________________________
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> > http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> >
> > Project Home: http://www.clusterlabs.org
> > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> > Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
> >
> 
> _______________________________________________
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> http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> 
> Project Home: http://www.clusterlabs.org
> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker