> On Fri, Sep 26, 2014 at 04:17:14AM +0200, Jan Hubicka wrote:
> > I was building libreoffice with profile feedback and I run into a message
> >
> > cannot load any more object with static TLS
> >
> > that took me a while to track as I did not see where static TLS is comming
> > out.
> > Ian pointed out to me that static variables with TLS storage also consume
> > static TLS even if they are in dynamic model. This is why I disabled
> > localization. Is there better way to handle this?
>
> Fix a glibc bug? It has been a while since I looked into glibc in
> any depth regarding TLS (2011-03), but I believe the l_tls_modid test
> here
> if (! RTLD_SINGLE_THREAD_P && imap->l_tls_modid > DTV_SURPLUS)
> _dl_signal_error (0, "dlopen", NULL, N_("\
> cannot load any more object with static TLS"));
>
> is wrong. The test is saying "if we have loaded a certain number of
> dynamic objects with TLS segments, refuse to dlopen any more
> containing TLS if we are multi-threaded".
>
> What it should be saying is "if we have loaded a certain number of
> dynamic objects with TLS segments *after we went multi-threaded*,
> refuse to open any more". In particular, any dynamic objects with TLS
> segments loaded at program startup should not be counted. This is
> because DTV_SURPLUS *extra* slots are allocated above those needed at
> program startup. At least, that's how I think it works.
Yeah, this also looks like very good idea to do (and would solve several
practical issues with this limit that I saw while googling for it).
Still if someone dlopens bazzilion of shared libraries built with profile
feedback and does so after going multithreaded, it should not hit the limit. So
I think we need GCC side solution too.
Honza
>
> --
> Alan Modra
> Australia Development Lab, IBM
