/*
131  * This is the function that decides how desirable a process is..
132  * You can weigh different processes against each other depending
133  * on what CPU they've run on lately etc to try to handle cache
134  * and TLB miss penalties.
135  *
136  * Return values:
137  *       -1000: never select this
138  *           0: out of time, recalculate counters (but it might still be
139  *              selected)
140  *         +ve: "goodness" value (the larger, the better)
141  *       +1000: realtime process, select this.
142  */
143 
144 static inline int goodness(struct task_struct * p, int this_cpu, struct mm_struct *this_mm)
145 {
146         int weight;
147 
148         /*
149          * select the current process after every other
150          * runnable process, but before the idle thread.
151          * Also, dont trigger a counter recalculation.
152          */
153         weight = -1;
154         if (p->policy & SCHED_YIELD)
155                 goto out;
156 
157         /*
158          * Non-RT process - normal case first.
159          */
160         if (p->policy == SCHED_OTHER) {
161                 /*
162                  * Give the process a first-approximation goodness value
163                  * according to the number of clock-ticks it has left.
164                  *
165                  * Don't do any other calculations if the time slice is
166                  * over..
167                  */
168                 weight = p->counter;
169                 if (!weight)
170                         goto out;
171                         
172 #ifdef CONFIG_SMP
173                 /* Give a largish advantage to the same processor...   */
174                 /* (this is equivalent to penalizing other processors) */
175                 if (p->processor == this_cpu)
176                         weight += PROC_CHANGE_PENALTY;
177 #endif
178 
179                 /* .. and a slight advantage to the current MM */
180                 if (p->mm == this_mm || !p->mm)
181                         weight += 1;
182                 weight += 20 - p->nice;
183                 goto out;
184         }
185 
186         /*
187          * Realtime process, select the first one on the
188          * runqueue (taking priorities within processes
189          * into account).
190          */
191         weight = 1000 + p->rt_priority;
192 out:
193         return weight;
194 }