[OpenAFS-devel] AFSD memory footprint

[Neulinger, Nathan]

I did some limited testing allocating, writing, and freeing a couple large
chunks of memory. On linux, it definately returns the memory to the O/S when
you free() it with redhat-6.2 or 7.1.  (I think glibc 2.1 and 2.2
respectively.)

I couldn't get hp or solaris to give me any meaningful results. (It didn't
look like malloc'd data was showing up in ps SZ column, but I may have been
doing something stupid.)

I'd say it'd certainly be worth free'ing the data on linux, and everywhere
else - if for no other reason than that Nikolai mentioned - just to be
correct.

-- Nathan

> -----Original Message-----
> From: Derek Atkins [mailto:warlord@MIT.EDU]
> Sent: Thursday, August 02, 2001 1:50 PM
> To: Neulinger, Nathan
> Cc: openafs-devel@openafs.org
> Subject: Re: [OpenAFS-devel] AFSD memory footprint
> 
> 
> That is one approach.. But then you have to wait and catch the child
> process when it ends.  Also, I think there might be a synchronization
> issue there, in terms of when you need to sweep the cache.
> 
> -derek
> 
> "Neulinger, Nathan" <nneul@umr.edu> writes:
> 
> > I think that'll probably depend on which os/kernel. Depends 
> on whether the
> > o/s will de-allocate when unused.
> > 
> > There might be another option - what about forking itself 
> and passing the
> > limited info needed, and then terminating the process that 
> did all the
> > allocations? (Not sure if this is feasible, just an idea.)
> > 
> > -- Nathan
> > 
> > > -----Original Message-----
> > > From: Derek Atkins [mailto:warlord@MIT.EDU]
> > > Sent: Thursday, August 02, 2001 1:29 PM
> > > To: openafs-devel@openafs.org
> > > Subject: [OpenAFS-devel] AFSD memory footprint
> > > 
> > > 
> > > So, afsd winds up mallocing a lot of memory during it's 
> cache sweep
> > > and startup stages.  I don't think it needs most of that 
> memory by the
> > > time it calls into the kernel.  Is there any reason that we don't
> > > 'free()' that memory before the last afs_syscall()?  I'm 
> thinking that
> > > this could potentially free a few megabytes of RAM.  Or 
> will it not
> > > matter since the virtual memory is already mapped into the process
> > > space?
> > > 
> > > -derek
> > > -- 
> > >        Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
> > >        Member, MIT Student Information Processing Board  (SIPB)
> > >        URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
> > >        warlord@MIT.EDU                        PGP key available
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> 
> -- 
>        Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
>        Member, MIT Student Information Processing Board  (SIPB)
>        URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
>        warlord@MIT.EDU                        PGP key available
>