Re: [patch 0/4] Series to allow a "const" file_operations struct

Eric Dumazet
2006-01-07T07:40:46Z

Andrew Morton a écrit :
> Eric Dumazet <dada1@cosmosbay.com> wrote:
>> On my x86_64 machine, I managed to reduce by 10% .data section by moving all
>> file_operations, but also 'address_space_operations', 'inode_operations,
>> super_operations, dentry_operations, seq_operations, ... to rodata section.
>>
>> size vmlinux*
>> text data bss dec hex filename
>> 2476156 522236 244868 3243260 317cfc vmlinux
>> 2588685 571348 246692 3406725 33fb85 vmlinux.old
>>
>
> Confused. Why should this result in an aggregate reduction in vmlinux size?
>
>

Sorry, vmlinux.old was with CONFIG_FRAME_POINTER and CONFIG_MODULES, not 'vmlinux'

If I add back CONFIG_FRAME_POINTER / CONFIG_MODULES on my config I get :

# size vmlinux
text data bss dec hex filename
2627717 523988 244868 3396573 33d3dd vmlinux

Aggregate reduction might be possible because of 'const' : Compiler (gcc-3.4.4
here) is free to make further optimizations ?

# size -A vmlinux
vmlinux :
section size addr
.text 2128492 18446744071563116544
__ex_table 15408 18446744071565245040
.rodata 256486 18446744071565260448
.pci_fixup 2112 18446744071565516944
__ksymtab 34336 18446744071565519056
__ksymtab_gpl 5488 18446744071565553392
__kcrctab 0 18446744071565558880
__kcrctab_gpl 0 18446744071565558880
__ksymtab_strings 54978 18446744071565558880
__param 2560 18446744071565613864
.data 408392 18446744071565616448
.bss 244868 18446744071566024896
.data.cacheline_aligned 23936 18446744071566270464
.data.read_mostly 7296 18446744071566294400
.vsyscall_0 319 18446744073699065856
.xtime_lock 8 18446744073699066176
.vxtime 48 18446744073699066192
.wall_jiffies 8 18446744073699066240
.sys_tz 8 18446744073699066256
.sysctl_vsyscall 4 18446744073699066272
.xtime 16 18446744073699066288
.jiffies 8 18446744073699066304
.vsyscall_1 47 18446744073699066880
.vsyscall_2 13 18446744073699067904
.vsyscall_3 13 18446744073699068928
.data.init_task 8192 18446744071566311424
.init.text 124192 18446744071566319616
.init.data 42584 18446744071566443808
.init.setup 2184 18446744071566486400
.initcall.init 1240 18446744071566488584
.con_initcall.init 24 18446744071566489824
.security_initcall.init 0 18446744071566489848
.altinstructions 139 18446744071566489848
.altinstr_replacement 93 18446744071566489987
.exit.text 2907 18446744071566490080
.init.ramfs 134 18446744071566495744
.data.percpu 30040 18446744071566495936
.comment 11808 0
.note.GNU-stack 0 0
Total 3408381

# size -A vmlinux.old
vmlinux.4 :
section size addr
.text 2131420 18446744071563116544
__ex_table 15408 18446744071565247968
.rodata 214318 18446744071565263392
.pci_fixup 2112 18446744071565477712
__ksymtab 34368 18446744071565479824
__ksymtab_gpl 5488 18446744071565514192
__kcrctab 0 18446744071565519680
__kcrctab_gpl 0 18446744071565519680
__ksymtab_strings 55010 18446744071565519680
__param 2560 18446744071565574696
.data 451848 18446744071565577280
.bss 246692 18446744071566029184
.data.cacheline_aligned 23744 18446744071566278656
.data.read_mostly 11328 18446744071566302400
.vsyscall_0 319 18446744073699065856
.xtime_lock 8 18446744073699066176
.vxtime 48 18446744073699066192
.wall_jiffies 8 18446744073699066240
.sys_tz 8 18446744073699066256
.sysctl_vsyscall 4 18446744073699066272
.xtime 16 18446744073699066288
.jiffies 8 18446744073699066304
.vsyscall_1 47 18446744073699066880
.vsyscall_2 13 18446744073699067904
.vsyscall_3 13 18446744073699068928
.data.init_task 8192 18446744071566319616
.init.text 124352 18446744071566327808
.init.data 42616 18446744071566452160
.init.setup 2208 18446744071566494784
.initcall.init 1248 18446744071566496992
.con_initcall.init 24 18446744071566498240
.security_initcall.init 0 18446744071566498264
.altinstructions 139 18446744071566498264
.altinstr_replacement 93 18446744071566498403
.exit.text 2891 18446744071566498496
.init.ramfs 134 18446744071566503936
.data.percpu 30040 18446744071566504128
.comment 11844 0
.note.GNU-stack 0 0
Total 3418569

Eric