[git pull] scheduler fixes

Ingo Molnar
2008-06-12T19:19:16Z

Linus,

please pull the latest scheduler fixes git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git sched-fixes-for-linus

thanks,

Ingo

------------------>
Lai Jiangshan (2):
sched: fair group: fix overflow(was: fix divide by zero)
sched: 64-bit: fix arithmetics overflow

Oleg Nesterov (1):
sched: fix TASK_WAKEKILL vs SIGKILL race

include/linux/sched.h | 13 +++++++++++++
kernel/sched.c | 22 ++++++++++++++--------
2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index ae0be3c..c5d3f84 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2026,6 +2026,19 @@ static inline int fatal_signal_pending(struct task_struct *p)
return signal_pending(p) && __fatal_signal_pending(p);
}

+static inline int signal_pending_state(long state, struct task_struct *p)
+{
+ if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
+ return 0;
+ if (!signal_pending(p))
+ return 0;
+
+ if (state & (__TASK_STOPPED | __TASK_TRACED))
+ return 0;
+
+ return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
+}
+
static inline int need_resched(void)
{
return unlikely(test_thread_flag(TIF_NEED_RESCHED));
diff --git a/kernel/sched.c b/kernel/sched.c
index bfb8ad8..eaf6751 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -312,12 +312,15 @@ static DEFINE_SPINLOCK(task_group_lock);
#endif

/*
- * A weight of 0, 1 or ULONG_MAX can cause arithmetics problems.
+ * A weight of 0 or 1 can cause arithmetics problems.
+ * A weight of a cfs_rq is the sum of weights of which entities
+ * are queued on this cfs_rq, so a weight of a entity should not be
+ * too large, so as the shares value of a task group.
* (The default weight is 1024 - so there's no practical
* limitation from this.)
*/
#define MIN_SHARES 2
-#define MAX_SHARES (ULONG_MAX - 1)
+#define MAX_SHARES (1UL << 18)

static int init_task_group_load = INIT_TASK_GROUP_LOAD;
#endif
@@ -1337,8 +1340,13 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight,
{
u64 tmp;

- if (!lw->inv_weight)
- lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)/(lw->weight+1);
+ if (!lw->inv_weight) {
+ if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
+ lw->inv_weight = 1;
+ else
+ lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
+ / (lw->weight+1);
+ }

tmp = (u64)delta_exec * weight;
/*
@@ -4159,12 +4167,10 @@ need_resched_nonpreemptible:
clear_tsk_need_resched(prev);

if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
- if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
- signal_pending(prev))) {
+ if (unlikely(signal_pending_state(prev->state, prev)))
prev->state = TASK_RUNNING;
- } else {
+ else
deactivate_task(rq, prev, 1);
- }
switch_count = &prev->nvcsw;
}