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authorCon Kolivas <kernel@kolivas.org>2006-03-31 02:31:26 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-31 12:18:58 -0800
commite72ff0bb2c163eb13014ba113701bd42dab382fe (patch)
tree6e4b8063442b3e020af474c2d4be124f01b0cb88 /kernel/sched.c
parente7c38cb49c6cc05bc11f70d9e9889da1c4a0d37f (diff)
[PATCH] sched: dont decrease idle sleep avg
We watch for tasks that sleep extended periods and don't allow one single prolonged sleep period from elevating priority to maximum bonus to prevent cpu bound tasks from getting high priority with single long sleeps. There is a bug in the current code that also penalises tasks that already have high priority. Correct that bug. Signed-off-by: Con Kolivas <kernel@kolivas.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 589e55a42214..7b371931114f 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -700,14 +700,19 @@ static int recalc_task_prio(task_t *p, unsigned long long now)
if (likely(sleep_time > 0)) {
/*
* User tasks that sleep a long time are categorised as
- * idle and will get just interactive status to stay active &
- * prevent them suddenly becoming cpu hogs and starving
- * other processes.
+ * idle. They will only have their sleep_avg increased to a
+ * level that makes them just interactive priority to stay
+ * active yet prevent them suddenly becoming cpu hogs and
+ * starving other processes.
*/
if (p->mm && p->sleep_type != SLEEP_NONINTERACTIVE &&
sleep_time > INTERACTIVE_SLEEP(p)) {
- p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG -
- DEF_TIMESLICE);
+ unsigned long ceiling;
+
+ ceiling = JIFFIES_TO_NS(MAX_SLEEP_AVG -
+ DEF_TIMESLICE);
+ if (p->sleep_avg < ceiling)
+ p->sleep_avg = ceiling;
} else {
/*
* Tasks waking from uninterruptible sleep are