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authorMiquel Raynal <miquel.raynal@bootlin.com>2019-11-17 18:34:01 +0100
committerMiquel Raynal <miquel.raynal@bootlin.com>2019-11-17 18:34:01 +0100
commit8389a7b909f252e74ea92b2794de8d660cfee96e (patch)
treea947f3080e953e4a44417389b3f2b69d4817be2e /kernel/sched/fair.c
parentad39b5a1ed68032292794b41a5f9e41ea69f8052 (diff)
parent83cba933a6db1dd4d7ac85170f99461fbc339eff (diff)
Merge tag 'spi-nor/for-5.5' into mtd/next
SPI NOR core changes: - introduce 'struct spi_nor_controller_ops', - clean the Register Operations methods, - use dev_dbg insted of dev_err for low level info, - fix retlen handling in sst_write(), - fix silent truncations in spi_nor_read and spi_nor_read_raw(), - fix the clearing of QE bit on lock()/unlock(), - rework the disabling of the block write protection, - rework the Quad Enable methods, - make sure nor->spimem and nor->controller_ops are mutually exclusive, - set default Quad Enable method for ISSI flashes, - add support for few flashes. SPI NOR controller drivers changes: - intel-spi: - support chips without software sequencer, - add support for Intel Cannon Lake and Intel Comet Lake-H flashes.
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 83ab35e2374f..682a754ea3e1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4926,20 +4926,28 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
if (++count > 3) {
u64 new, old = ktime_to_ns(cfs_b->period);
- new = (old * 147) / 128; /* ~115% */
- new = min(new, max_cfs_quota_period);
-
- cfs_b->period = ns_to_ktime(new);
-
- /* since max is 1s, this is limited to 1e9^2, which fits in u64 */
- cfs_b->quota *= new;
- cfs_b->quota = div64_u64(cfs_b->quota, old);
-
- pr_warn_ratelimited(
- "cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us %lld, cfs_quota_us = %lld)\n",
- smp_processor_id(),
- div_u64(new, NSEC_PER_USEC),
- div_u64(cfs_b->quota, NSEC_PER_USEC));
+ /*
+ * Grow period by a factor of 2 to avoid losing precision.
+ * Precision loss in the quota/period ratio can cause __cfs_schedulable
+ * to fail.
+ */
+ new = old * 2;
+ if (new < max_cfs_quota_period) {
+ cfs_b->period = ns_to_ktime(new);
+ cfs_b->quota *= 2;
+
+ pr_warn_ratelimited(
+ "cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+ smp_processor_id(),
+ div_u64(new, NSEC_PER_USEC),
+ div_u64(cfs_b->quota, NSEC_PER_USEC));
+ } else {
+ pr_warn_ratelimited(
+ "cfs_period_timer[cpu%d]: period too short, but cannot scale up without losing precision (cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+ smp_processor_id(),
+ div_u64(old, NSEC_PER_USEC),
+ div_u64(cfs_b->quota, NSEC_PER_USEC));
+ }
/* reset count so we don't come right back in here */
count = 0;