Re: [PATCH] x86_64: Do not use -ffunction-sections for modules

From: Sergey Vlasov
Date: Wed Jun 21 2006 - 12:50:05 EST


On Wed, Jun 21, 2006 at 06:41:33PM +0200, Andi Kleen wrote:
> The correct mailing list is still discuss@xxxxxxxxxx

Noted.

> On Thursday 01 January 1970 01:00, Sergey Vlasov wrote:
> > Currently CONFIG_REORDER uses -ffunction-sections for all code;
> > however, creating a separate section for each function is not useful
> > for modules and just adds bloat.
>
> You mean the ELF files are larger?

Yes, and all these sections are then reported in sysfs (BTW, what programs
really use /sys/module/*/sections/* files?).

> .text/.data size shouldn't > change in theory.

Actually, it does change by a small amount for some reason - even
increases by about 100 bytes in some cases; however, I suppose that the
size reported by /proc/modules and lsmod is more important, and it
decreases:

before:
ext3 138896 4
jbd 58152 1 ext3
mbcache 10248 1 ext3
sata_nv 11140 13
libata 75928 1 sata_nv
sd_mod 21912 6
scsi_mod 155824 3 usb_storage,libata,sd_mod
ide_disk 17536 0
ide_generic 1664 0 [permanent]
amd74xx 15280 0 [permanent]
generic 5892 0 [permanent]
ide_core 150624 6 ide_cd,usb_storage,ide_disk,ide_generic,amd74xx,generic

after:
ext3 129040 4
jbd 53672 1 ext3
mbcache 9608 1 ext3
sata_nv 10756 13
libata 69784 1 sata_nv
sd_mod 20760 6
scsi_mod 145200 3 usb_storage,libata,sd_mod
ide_disk 16384 0
ide_generic 1664 0 [permanent]
amd74xx 14896 0 [permanent]
generic 5764 0 [permanent]
ide_core 140768 6 ide_cd,usb_storage,ide_disk,ide_generic,amd74xx,generic

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