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

From: Andrew Morton
Date: Mon Jun 30 2014 - 16:58:00 EST


On Mon, 30 Jun 2014 13:49:30 -0700 Joe Perches <joe@xxxxxxxxxxx> wrote:

> On Mon, 2014-06-30 at 13:39 -0700, Andrew Morton wrote:
> > On Mon, 30 Jun 2014 21:03:17 +0200 Fabian Frederick <fabf@xxxxxxxxx> 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.

These things involve tradeoffs. A constant dribble of
do-nothing-useful patches just isn't worth the effort on either end,
IMO.

> > 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

doh, I only looked at base.o.

I added this to the changelog. It should have been there originally,
please.

text data bss dec hex filename
6817 404 1984 9205 23f5 kernel/user_namespace.o-before
6913 308 1984 9205 23f5 kernel/user_namespace.o-after

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