The patch titled
Avoid divide by zero errors in sched.c
has been added to the -mm tree. Its filename is
sched-correct_smp_nice_bias-fix.patch
Patches currently in -mm which might be from [EMAIL PROTECTED] are
disk-quotas-fail-when-etc-mtab-is-symlinked-to-proc-mounts.patch
sched-correct_smp_nice_bias-fix.patch
From: Dave Kleikamp <[EMAIL PROTECTED]>
This patch fixes a divide-by-zero error that I hit on a two-way i386
machine. rq->nr_running is tested to be non-zero, but may change by the
time it is used in the division. Saving the value to a local variable
ensures that the same value that is checked is used in the division.
Signed-off-by: Dave Kleikamp <[EMAIL PROTECTED]>
Cc: Con Kolivas <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
kernel/sched.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)
diff -puN kernel/sched.c~sched-correct_smp_nice_bias-fix kernel/sched.c
--- 25/kernel/sched.c~sched-correct_smp_nice_bias-fix Wed Aug 17 14:39:38 2005
+++ 25-akpm/kernel/sched.c Wed Aug 17 14:39:38 2005
@@ -970,15 +970,16 @@ void kick_process(task_t *p)
static inline unsigned long __source_load(int cpu, int type, enum idle_type
idle)
{
runqueue_t *rq = cpu_rq(cpu);
+ unsigned long running = rq->nr_running;
unsigned long source_load, cpu_load = rq->cpu_load[type-1],
- load_now = rq->nr_running * SCHED_LOAD_SCALE;
+ load_now = running * SCHED_LOAD_SCALE;
if (type == 0)
source_load = load_now;
else
source_load = min(cpu_load, load_now);
- if (rq->nr_running > 1 || (idle == NOT_IDLE && rq->nr_running))
+ if (running > 1 || (idle == NOT_IDLE && running))
/*
* If we are busy rebalancing the load is biased by
* priority to create 'nice' support across cpus. When
@@ -987,7 +988,7 @@ static inline unsigned long __source_loa
* prevent idle rebalance from trying to pull tasks from a
* queue with only one running task.
*/
- source_load = source_load * rq->prio_bias / rq->nr_running;
+ source_load = source_load * rq->prio_bias / running;
return source_load;
}
@@ -1003,16 +1004,17 @@ static inline unsigned long source_load(
static inline unsigned long __target_load(int cpu, int type, enum idle_type
idle)
{
runqueue_t *rq = cpu_rq(cpu);
+ unsigned long running = rq->nr_running;
unsigned long target_load, cpu_load = rq->cpu_load[type-1],
- load_now = rq->nr_running * SCHED_LOAD_SCALE;
+ load_now = running * SCHED_LOAD_SCALE;
if (type == 0)
target_load = load_now;
else
target_load = max(cpu_load, load_now);
- if (rq->nr_running > 1 || (idle == NOT_IDLE && rq->nr_running))
- target_load = target_load * rq->prio_bias / rq->nr_running;
+ if (running > 1 || (idle == NOT_IDLE && running))
+ target_load = target_load * rq->prio_bias / running;
return target_load;
}
_
-
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