Hello,
Here is a small clean-up which changes some goto's into loops for
move_tasks(). It makes the code a bit easier to read (the two loops are
explicit now) and it also reduces the number of lines. I've checked the
patch on x86 and IA-64 (with 4 processors).
Concerning the size of the binary, on x86, depending on the options, it
can be one instruction (4 bytes) bigger to one instruction smaller. On
IA-64, it suprisingly saves 4 instructions (64 bytes) most of the time.
This patch was done for 2.6.12-rc1 but should apply against 2.6.12-rc3
cleanly. It's quite trivial and makes the clode cleaner, please apply.
Eric Piel
--
Small clean-up of move_tasks(). Converts the goto's into two eplicit loops.
Signed-off-by: Eric Piel <[email protected]>
--- linux-2.6.12-rc1/kernel/sched.c.bak 2005-04-03 00:21:07.000000000 +0200
+++ linux-2.6.12-rc1/kernel/sched.c 2005-04-03 01:08:28.000000000 +0200
@@ -1695,50 +1695,37 @@ static int move_tasks(runqueue_t *this_r
new_array:
/* Start searching at priority 0: */
- idx = 0;
-skip_bitmap:
- if (!idx)
- idx = sched_find_first_bit(array->bitmap);
- else
- idx = find_next_bit(array->bitmap, MAX_PRIO, idx);
- if (idx >= MAX_PRIO) {
- if (array == busiest->expired && busiest->active->nr_active) {
- array = busiest->active;
- dst_array = this_rq->active;
- goto new_array;
- }
- goto out;
- }
-
- head = array->queue + idx;
- curr = head->prev;
-skip_queue:
- tmp = list_entry(curr, task_t, run_list);
-
- curr = curr->prev;
-
- if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle)) {
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
- }
+ for (idx = sched_find_first_bit(array->bitmap);
+ idx < MAX_PRIO;
+ idx = find_next_bit(array->bitmap, MAX_PRIO, idx + 1)) {
+ head = array->queue + idx;
+ for (curr = head->prev;
+ curr != head; ) {
+ tmp = list_entry(curr, task_t, run_list);
+
+ curr = curr->prev;
+
+ if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle))
+ continue;
#ifdef CONFIG_SCHEDSTATS
- if (task_hot(tmp, busiest->timestamp_last_tick, sd))
- schedstat_inc(sd, lb_hot_gained[idle]);
+ if (task_hot(tmp, busiest->timestamp_last_tick, sd))
+ schedstat_inc(sd, lb_hot_gained[idle]);
#endif
- pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
- pulled++;
+ pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
+ pulled++;
- /* We only want to steal up to the prescribed number of tasks. */
- if (pulled < max_nr_move) {
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
+ /* We only want to steal up to the prescribed number of tasks. */
+ if (pulled >= max_nr_move)
+ goto out;
+ }
}
+ if (array == busiest->expired && busiest->active->nr_active) {
+ array = busiest->active;
+ dst_array = this_rq->active;
+ goto new_array;
+ }
out:
/*
* Right now, this is the only place pull_task() is called,
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