On Thu, Aug 20, 2020 at 06:15:15PM +0000, Luck, Tony wrote:
> >> How much does vmlinux size grow with your change?
> >>
> >
> > It seems to get smaller.
> >
> > -rwxrwxr-x 1 yghannam yghannam 807634088 Aug 20 17:51 vmlinux-32banks
> > -rwxrwxr-x 1 yghannam yghannam 807634072 Aug 20 17:50 vmlinux-64banks
>
> You need to run:
>
> $ size vmlinux
> text data bss dec hex filename
> 20334755 12569682 14798924 47703361 2d7e541
> vmlinux
>
> Likely the extra space is added to the third element ("bss"). That doesn't
> show
> up in the vmlinux file, but does add to memory footprint while running.
Thanks. Yeah, they're identical:
text data bss dec hex filename
15710076 13519306 5398528 34627910 2106146
vmlinux-32banks
15710076 13519306 5398528 34627910 2106146
vmlinux-64banks
I did a quick audit of the statically allocated data structures which
use MAX_NR_BANKS.
Global bitmaps:
- core.c / mce_banks_ce_disabled
- core.c / all_banks
- core.c / valid_banks
- core.c / toclear
- Total: 32 new bits * 4 bitmaps = 16 new bytes
Per-CPU bitmaps:
- core.c / mce_poll_banks
- intel.c / mce_banks_owned
- Total: 32 new bits * 2 bitmaps = 8 new bytes
The bitmaps are arrays of longs. So this change will only affect 32-bit
execution (I assume), since there will be one additional long used.
There will be no additional memory use on 64-bit execution, because the
size of long is 64 bits.
Global structs:
- amd.c / struct smca_bank smca_banks[]: 16 bytes per bank
- core.c / struct mce_bank_dev mce_bank_devs[]: 56 bytes per bank
- Total: 32 new banks * (16 + 56) bytes = 2304 new bytes
Per-CPU structs:
- core.c / struct mce_bank mce_banks_array[]: 16 bytes per bank
- Total: 32 new banks * 16 bytes = 512 new bytes
32-bit
Total global size increase: 2320 bytes
Total per-CPU size increase: 520 bytes
64-bit
Total global size increase: 2304 bytes
Total per-CPU size increase: 512 bytes
Is this okay?
Thanks,
Yazen
