From: John Hawkes <hawkes@google.engr.sgi.com>
Here is a patch against 2.6.1-mm3 that I believe restores the "sched_clock
fix" from -mm2. I've also fixed the declaration of timestamp_last_tick to
be "unsigned long long", to match task->timestamp and sched_clock().
---
kernel/sched.c | 15 ++++++---------
1 files changed, 6 insertions(+), 9 deletions(-)
diff -puN kernel/sched.c~sched-clock-fixes kernel/sched.c
--- 25/kernel/sched.c~sched-clock-fixes 2004-01-24 16:20:39.000000000 -0800
+++ 25-akpm/kernel/sched.c 2004-01-24 16:20:39.000000000 -0800
@@ -205,7 +205,8 @@ struct prio_array {
struct runqueue {
spinlock_t lock;
unsigned long nr_running, nr_switches, expired_timestamp,
- nr_uninterruptible, timestamp_last_tick;
+ nr_uninterruptible;
+ unsigned long long timestamp_last_tick;
task_t *curr, *idle;
struct mm_struct *prev_mm;
prio_array_t *active, *expired, arrays[2];
@@ -1251,8 +1252,7 @@ static inline void pull_task(runqueue_t
*/
static inline
int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu,
- unsigned long long now, struct sched_domain *domain,
- enum idle_type idle)
+ struct sched_domain *domain, enum idle_type idle)
{
/*
* We do not migrate tasks that are:
@@ -1268,8 +1268,8 @@ int can_migrate_task(task_t *p, runqueue
/* Aggressive migration if we've failed balancing */
if (idle == NEWLY_IDLE ||
domain->nr_balance_failed < domain->cache_nice_tries) {
- unsigned long long delta = now - p->timestamp;
- if (delta < domain->cache_hot_time)
+ if ((rq->timestamp_last_tick - p->timestamp)
+ < domain->cache_hot_time)
return 0;
}
@@ -1287,7 +1287,6 @@ static int move_tasks(runqueue_t *this_r
unsigned long max_nr_move, struct sched_domain *domain,
enum idle_type idle)
{
- unsigned long long now;
int idx;
int pulled = 0;
prio_array_t *array, *dst_array;
@@ -1297,8 +1296,6 @@ static int move_tasks(runqueue_t *this_r
if (max_nr_move <= 0 || busiest->nr_running <= 1)
goto out;
- now = sched_clock();
-
/*
* We first consider expired tasks. Those will likely not be
* executed in the near future, and they are most likely to
@@ -1337,7 +1334,7 @@ skip_queue:
curr = curr->prev;
- if (!can_migrate_task(tmp, busiest, this_cpu, now, domain, idle)) {
+ if (!can_migrate_task(tmp, busiest, this_cpu, domain, idle)) {
if (curr != head)
goto skip_queue;
idx++;
_