* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-fixes:
sched: fix share (re)distribution
softlockup: fix NOHZ wakeup
seqlock: livelock fix
/* Start of read calculation -- fetch last complete writer token */
static __always_inline unsigned read_seqbegin(const seqlock_t *sl)
{
- unsigned ret = sl->sequence;
+ unsigned ret;
+
+repeat:
+ ret = sl->sequence;
smp_rmb();
+ if (unlikely(ret & 1)) {
+ cpu_relax();
+ goto repeat;
+ }
+
return ret;
}
-/* Test if reader processed invalid data.
- * If initial values is odd,
- * then writer had already started when section was entered
- * If sequence value changed
- * then writer changed data while in section
- *
- * Using xor saves one conditional branch.
+/*
+ * Test if reader processed invalid data.
+ *
+ * If sequence value changed then writer changed data while in section.
*/
-static __always_inline int read_seqretry(const seqlock_t *sl, unsigned iv)
+static __always_inline int read_seqretry(const seqlock_t *sl, unsigned start)
{
smp_rmb();
- return (iv & 1) | (sl->sequence ^ iv);
+
+ return (sl->sequence != start);
}
/* Start of read using pointer to a sequence counter only. */
static inline unsigned read_seqcount_begin(const seqcount_t *s)
{
- unsigned ret = s->sequence;
+ unsigned ret;
+
+repeat:
+ ret = s->sequence;
smp_rmb();
+ if (unlikely(ret & 1)) {
+ cpu_relax();
+ goto repeat;
+ }
return ret;
}
-/* Test if reader processed invalid data.
- * Equivalent to: iv is odd or sequence number has changed.
- * (iv & 1) || (*s != iv)
- * Using xor saves one conditional branch.
+/*
+ * Test if reader processed invalid data because sequence number has changed.
*/
-static inline int read_seqcount_retry(const seqcount_t *s, unsigned iv)
+static inline int read_seqcount_retry(const seqcount_t *s, unsigned start)
{
smp_rmb();
- return (iv & 1) | (s->sequence ^ iv);
+
+ return s->sequence != start;
}
aggregate(tg, sd)->task_weight = task_weight;
}
-/*
- * Redistribute tg->shares amongst all tg->cfs_rq[]s.
- */
-static void __aggregate_redistribute_shares(struct task_group *tg)
-{
- int i, max_cpu = smp_processor_id();
- unsigned long rq_weight = 0;
- unsigned long shares, max_shares = 0, shares_rem = tg->shares;
-
- for_each_possible_cpu(i)
- rq_weight += tg->cfs_rq[i]->load.weight;
-
- for_each_possible_cpu(i) {
- /*
- * divide shares proportional to the rq_weights.
- */
- shares = tg->shares * tg->cfs_rq[i]->load.weight;
- shares /= rq_weight + 1;
-
- tg->cfs_rq[i]->shares = shares;
-
- if (shares > max_shares) {
- max_shares = shares;
- max_cpu = i;
- }
- shares_rem -= shares;
- }
-
- /*
- * Ensure it all adds up to tg->shares; we can loose a few
- * due to rounding down when computing the per-cpu shares.
- */
- if (shares_rem)
- tg->cfs_rq[max_cpu]->shares += shares_rem;
-}
-
/*
* Compute the weight of this group on the given cpus.
*/
unsigned long shares = 0;
int i;
-again:
for_each_cpu_mask(i, sd->span)
shares += tg->cfs_rq[i]->shares;
- /*
- * When the span doesn't have any shares assigned, but does have
- * tasks to run do a machine wide rebalance (should be rare).
- */
- if (unlikely(!shares && aggregate(tg, sd)->rq_weight)) {
- __aggregate_redistribute_shares(tg);
- goto again;
- }
+ if ((!shares && aggregate(tg, sd)->rq_weight) || shares > tg->shares)
+ shares = tg->shares;
aggregate(tg, sd)->shares = shares;
}
sub_preempt_count(HARDIRQ_OFFSET);
}
+ touch_softlockup_watchdog();
/*
* Cancel the scheduled timer and restore the tick
*/