Re: [RFC 1/1] proc: constify seq_operations

[Joe Perches <joe@perches.com>]

On Mon, 2014-06-30 at 13:39 -0700, Andrew Morton wrote:
> On Mon, 30 Jun 2014 21:03:17 +0200 Fabian Frederick <fabf@skynet.be> wrote:
> 
> > proc_uid_seq_operations, proc_gid_seq_operations and proc_projid_seq_operations
> > are only called in proc_id_map_open with seq_open as
> > const struct seq_operations so we can constify the 3 structures and update
> > proc_id_map_open prototype.
> 
> There are an absolutely enormous number of places where we could
> constify things.

Which would be a good thing.

>   For sheer sanity's sake I'm not inclined to churn the
> code in this way unless a patch provides some sort of runtime benefit. 
> And this particular patch doesn't appear to change the generated code
> at all.

It moves ~100 bytes from data to text
(gcc 4.8)

$ size kernel/user_namespace.o*
   text	   data	    bss	    dec	    hex	filename
   6676	   3107	   2248	  12031	   2eff	kernel/user_namespace.o.new
   6580	   3211	   2248	  12039	   2f07	kernel/user_namespace.o.old