Re: [Qemu-devel] [PATCH v2 0/7] build-sys: Fix iscsi module loading failure

[Fam Zheng]

On Thu, 08/28 12:17, Stefan Hajnoczi wrote:
> On Mon, Aug 25, 2014 at 10:27:07AM +0800, Fam Zheng wrote:
> > On Fri, 08/22 14:35, Stefan Hajnoczi wrote:
> > > Did you compare the before/after binary size with your patch?  Please
> > > use size(1).
> > 
> > Before:
> > 
> > text     data     bss      dec       hex     filename
> > 24264    3016     8        27288     6a98    
> > /home/fam/build/master/block-iscsi.so
> > 24264    3016     8        27288     6a98    
> > /home/fam/build/master/block/iscsi.so
> > 35356    2272     4440     42068     a454    
> > /home/fam/build/master/fsdev/virtfs-proxy-helper
> > 392541   7568     4672     404781    62d2d   /home/fam/build/master/qemu-ga
> > 878979   33168    4204568  5116715   4e132b  /home/fam/build/master/qemu-img
> > 904801   57784    4208664  5171249   4ee831  /home/fam/build/master/qemu-io
> > 854255   32872    4204504  5091631   4db12f  /home/fam/build/master/qemu-nbd
> > 4896094  1293960  4727496  10917550  a696ae  
> > /home/fam/build/master/x86_64-softmmu/qemu-system-x86_64
> > 
> > After:
> > 
> > text     data     bss      dec       hex     filename
> > 23852    2992     8        26852     68e4    
> > /home/fam/build/iscsi-modules/block-iscsi.so
> > 23852    2992     8        26852     68e4    
> > /home/fam/build/iscsi-modules/block/iscsi.so
> > 509345   32488    5192     547025    858d1   
> > /home/fam/build/iscsi-modules/fsdev/virtfs-proxy-helper
> > 563169   33312    5192     601673    92e49   
> > /home/fam/build/iscsi-modules/qemu-ga
> > 966709   58304    4204632  5229645   4fcc4d  
> > /home/fam/build/iscsi-modules/qemu-img
> > 940145   58088    4208792  5207025   4f73f1  
> > /home/fam/build/iscsi-modules/qemu-io
> > 943434   58048    4204632  5206114   4f7062  
> > /home/fam/build/iscsi-modules/qemu-nbd
> > 4904197  1293944  4727560  10925701  a6b685  
> > /home/fam/build/iscsi-modules/x86_64-softmmu/qemu-system-x86_64
> 
> It doesn't have a big impact on the QEMU binary.  The QEMU tools do get
> a bit bloated though.
> 
> I guess I'm happy with this approach.
> 

OK. I'm working on an alternative approach (-Wl,-u,SYMBOL) as suggested by the
binutils developer:

https://sourceware.org/bugzilla/show_bug.cgi?id=17306#c5

(Also as said in the comment, --just-symbols may not be a right way to do this.)

I'll post it later for comparison, and we can choose one between them.

Thanks,
Fam