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

From: Eric Dumazet
Date: Fri Jan 06 2006 - 17:45:02 EST


Arjan van de Ven a écrit :
On Fri, 2006-01-06 at 22:45 +0100, Arjan van de Ven wrote:
Hi,

this series allows drivers to have "const" file_operations, by making
the f_ops field in the inode const. This has another benefit, there have

ok there was a sentence missing here. The first benefit is that this
moves these hot datastructures to the rodata section, which means they
won't accidentally be doing false cacheline sharing.


Definitly a good thing I agree.

But your patches miss to really declare all 'struct file_operations' as const, dont they ?


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

Eric

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