Re: sched: 64-bit nr_running

[Daniel Walker <dwalker@mvista.com>]

On Mon, 2006-05-15 at 18:34 +0200, Ingo Molnar wrote:

> well for performance it's usually best to just have the native
> machine 
> word size (i.e. long), unless there's some compelling data-structure 
> size argument. In any case it's not uncommon to use 'long' for such 
> types, even though some other aspect of the kernel limits it to less 
> than 64 (or even 32) bits.

I also noticed that struct task_struct -> state uses a volatile long ,
but it seems to only use a few bits . exit_state also uses a long type
and only uses a few bits .. They could be combined into one long (or
even and int) .. I noticed the comment below,

 * We have two separate sets of flags: task->state
 * is about runnability, while task->exit_state are
 * about the task exiting. Confusing, but this way
 * modifying one set can't modify the other one by
 * mistake.

I think if it was all inside macro's it wouldn't be so easy to
accidentally set the exit_state when touching just state .. 

Daniel

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