Re: [PATCH 2 of 4] Introduce i386 fibril scheduling

[Davide Libenzi]

On Tue, 30 Jan 2007, Zach Brown wrote:

> +	/* 
> +	 * XXX The idea is to copy all but the actual call stack.  Obviously
> +	 * this is wildly arch-specific and belongs abstracted out.
> +	 */
> +	*next->ti = *ti;
> +	*thread_info_pt_regs(next->ti) = *thread_info_pt_regs(ti);

arch copy_thread_info()?



> +	current->per_call = next->per_call;

Pointer instead of structure copy? percall_clone()/percall_free()?



> +	/* always switch to a runnable fibril if we aren't being preempted */
> +	if (unlikely(!(preempt_count() & PREEMPT_ACTIVE) &&
> +		     !list_empty(&prev->runnable_fibrils))) {
> +		schedule_fibril(prev);
> +		/* 
> +		 * finish_fibril_switch() drops the rq lock and enables
> +		 * premption, but the popfl disables interrupts again.  Watch
> +		 * me learn how context switch locking works before your very
> +		 * eyes!  XXX This will need to be fixed up by throwing
> +		 * together something like the prepare_lock_switch() path the
> +		 * scheduler does.  Guidance appreciated!
> +		 */
> +		local_irq_enable();
> +		return;
> +	}

Yes, please (prepare/finish) ... ;)



- Davide


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