Messages in this thread | | | Date | Wed, 1 Jul 2009 00:09:32 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] reduce export symbol CRC table size on 64-bit archs |
| |
* Jan Beulich <JBeulich@novell.com> wrote:
> Since these CRCs are really only 32-bit quantities, there's no > need to store them in 64-bit slots. Since, however, gcc doesn't > allow respective initializations, asm() constructs get used to > create the CRC tables (and its for that reason that the patch only > makes x86-64 and ia64 utilize that functionality, as I can't > verify this doesn't break in some subtle way elsewhere). > > Observed size reduction (x86-64): > - 16k kernel resident size > - 2k module resident size > - 1M vmlinux image size > > If the asm() construct could be extended to all architectures, and > if modpost would guarantee generation of CRCs for all exported, > then the __crc_* symbols wouldn't need to be declared weak > anymore, could hence remain local to the exporting object. By > adding -Wa,-strip-local-absolute to the second compilation step > the __crc_* symbols could even be prevented from making it into > any object file at all. > > Signed-off-by: Jan Beulich <jbeulich@novell.com>
> > --- > arch/ia64/include/asm/module.h | 2 ++ > arch/x86/include/asm/module.h | 1 + > include/linux/module.h | 41 ++++++++++++++++++++++++++--------------- > include/linux/moduleparam.h | 10 +++++++++- > kernel/module.c | 26 +++++++++++++------------- > scripts/genksyms/genksyms.c | 16 ++++++++-------- > 6 files changed, 59 insertions(+), 37 deletions(-)
No objections to the (minor) x86 bits.
Ingo
| |