Re: [PATCH] xen, credit2: Avoid extra c2t calcuation in csched_runtime

[George Dunlap <george.dunlap@eu.citrix.com>]

On 24/01/13 15:55, George Dunlap wrote:
>>
>>>       struct csched_runqueue_data *rqd = RQD(ops, cpu);
>>>       struct list_head *runq = &rqd->runq;
>>>         if ( is_idle_vcpu(snext->vcpu) )
>>>           return CSCHED_MAX_TIMER;
>>>   -    /* Basic time */
>>> -    time = c2t(rqd, snext->credit, snext);
>>> +    /* General algorithm:
>>> +     * 1) Run until snext's credit will be 0
>>> +     * 2) But if someone is waiting, run until snext's credit is equal
>>> +     * to his
>>> +     * 3) But never run longer than MAX_TIMER or shorter than 
>>> MIN_TIMER.
>>> +     */
>>>   -    /* Next guy on runqueue */
>>> +    /* 1) Basic time: Run until credit is 0. */
>>> +    rt_credit = snext->credit;
>>> +
>>> +    /* 2) If there's someone waiting whose credit is positive,
>> ... who's ...?
>
> Nope. :-)  "Who's" is short for "who is".  "Whose" is a pronoun which 
> links back to "someone waiting".  (I suppose "whose" is the person 
> version of "which", which I used in both the previous sentence and 
> this one.)

OK, for the really serious grammar students:

"Whose" isn't a pronoun, it's an adjective indicating "owned by who" or 
"of who"; in this case, "whose" is modifying "credit".  It's a similar 
construction to the following:

"If there's someone waiting who has positive credit, ..."

  -George