Re: [PATCH v2 -mm 8/9] netconsole: Support multiple logging targets

Satyam Sharma
2007-07-11T04:04:31Z

Hi,

On Tue, 10 Jul 2007, Duane Griffin wrote:
> On 10/07/07, Satyam Sharma <ssatyam@cse.iitk.ac.in> wrote:
> > + /* Avoid taking lock and disabling interrupts unnecessarily */
> > + if (unlikely(list_empty(&target_list)))
> > + return;
>
> Is the unlikely a good idea here? Not having any targets may be
> unusual but it isn't ridiculous. It might even be a sensible default
> for distros.

Hmm, I put it in there because I expected that the user must have had
at least one target configured (added to target_list) if he's got the
module loaded/built-in (and netconsole registered), which is when this
function would be triggered anyway.

> My (very limited) understanding of unlikely is that it
> could impose a very large penalty in that case and would make a very
> marginal difference at best in the common case.

I wouldn't call it a large penalty, but yeah, probably the unlikely()
there isn't all that important either.

Satyam