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    DateFri, 23 Feb 2007 15:08:55 -0800 (PST)
    FromDavide Libenzi <>
    SubjectRe: [patch 04/13] syslets: core code
    On Wed, 21 Feb 2007, Ingo Molnar wrote:
    
    > +asmlinkage long
    > +sys_threadlet_on(unsigned long restore_stack,
    > +		 unsigned long restore_eip,
    > +		 struct async_head_user __user *ahu)
    > +{
    > +	struct task_struct *t = current;
    > +	struct async_head *ah = t->ah;
    > +	struct async_thread *at = &t->__at;
    > +	long ret;
    > +
    > +	/*
    > +	 * Do not allow recursive calls of sys_threadlet_on():
    > +	 */
    > +	if (t->async_ready || t->at)
    > +		return -EINVAL;
    > +
    > +	if (unlikely(!ah)) {
    > +		ret = init_head(ah, t, ahu);
    > +		if (ret)
    > +			return ret;
    > +		ah = t->ah;
    > +	}
    > +
    > +	if (unlikely(list_empty(&ah->ready_async_threads))) {
    > +		ret = refill_cachemiss_pool(ah, t, ahu);
    > +		if (ret)
    > +			return ret;
    > +	}
    > +
    > +	t->async_ready = at;
    > +	ah->restore_stack = restore_stack;
    > +	ah->restore_eip = restore_eip;
    > +
    > +	ah->ahu = ahu;
    > +
    > +	return 0;
    > +}
    > +
    > +asmlinkage long sys_threadlet_off(void)
    > +{
    > +	struct task_struct *t = current;
    > +	struct async_head *ah = t->ah;
    > +
    > +	/*
    > +	 * Are we still executing as head?
    > +	 */
    > +	if (ah) {
    > +		t->async_ready = NULL;
    > +
    > +		return 1;
    > +	}
    > +
    > +	/*
    > +	 * We got turned into a cachemiss thread,
    > +	 * return to user-space, which can do
    > +	 * the notification, etc:
    > +	 */
    > +	return 0;
    > +}
    
    If we have a new syscall that does the exec, we can save the two on/off 
    calls. Also, the complete_thread() thingy can be done automatically from 
    inside the kernel upon function return, by hence making the threadlet 
    function look like a normal thread function:
    
    long thfn(void *) {
    	...
    	return error;
    }
    No?
    
    
    
    - Davide
    
    
    -
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