Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1235186

Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT

Show all headers | View raw

[ Resend with a "Reply-all" this time! ]

On Tue, 29 Sep 2015 11:28:26 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> As per commit d86ee4809d03 ("sched: optimize cond_resched()") we need
> PREEMPT_ACTIVE to avoid cond_resched() from working before the
> scheduler is setup.
> 
> However, keeping preemption disabled should do the same thing already,
> making the PREEMPT_ACTIVE part entirely redundant.

Thus PREEMPT_ACTIVE wasn't needed at that commit either, or was it?

> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>  include/linux/sched.h |    7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -608,17 +608,14 @@ struct task_cputime_atomic {
>  /*
>   * Disable preemption until the scheduler is running.
>   * Reset by start_kernel()->sched_init()->init_idle().
> - *
> - * We include PREEMPT_ACTIVE to avoid cond_resched() from working
> - * before the scheduler is active -- see should_resched().
>   */
> -#define INIT_PREEMPT_COUNT	(PREEMPT_DISABLED + PREEMPT_ACTIVE)
> +#define INIT_PREEMPT_COUNT	PREEMPT_DISABLED

I can't find anything wrong with this.

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

>  
>  /**
>   * struct thread_group_cputimer - thread group interval timer counts
>   * @cputime_atomic:	atomic thread group interval timers.
>   * @running:		non-zero when there are timers running and
> - * 			@cputime receives updates.
> + *			@cputime receives updates.
>   *
>   * This structure contains the version of task_cputime, above, that is
>   * used for thread group CPU timer calculations.
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra <peterz@infradead.org> - 2015-09-29 11:50 +0200
  [tip:sched/core] sched/core: Simplify INIT_PREEMPT_COUNT tip-bot for Peter Zijlstra <tipbot@zytor.com> - 2015-09-29 12:40 +0200
  Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Frederic Weisbecker <fweisbec@gmail.com> - 2015-09-29 15:30 +0200
  Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Steven Rostedt <rostedt@goodmis.org> - 2015-09-29 16:50 +0200
    Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra <peterz@infradead.org> - 2015-09-29 17:00 +0200
  Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Steven Rostedt <rostedt@goodmis.org> - 2015-09-29 17:10 +0200
    Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra <peterz@infradead.org> - 2015-09-29 17:20 +0200

csiph-web