The patch titled
sched: skip updating rq's next_balance under null SD
has been removed from the -mm tree. Its filename was
sched-skip-updating-rqs-next_balance-under-null-sd.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: sched: skip updating rq's next_balance under null SD
From: "Siddha, Suresh B" <suresh.b.siddha@xxxxxxxxx>
Was playing with sched_smt_power_savings/sched_mc_power_savings and found out
that while the scheduler domains are reconstructed when sysfs settings change,
rebalance_domains() can get triggered with null domain on other cpus, which is
setting next_balance to jiffies + 60*HZ. Resulting in no idle/busy balancing
for 60 seconds.
Fix this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sched.c | 14 ++++++++++++--
1 files changed, 12 insertions(+), 2 deletions(-)
diff -puN kernel/sched.c~sched-skip-updating-rqs-next_balance-under-null-sd kernel/sched.c
--- a/kernel/sched.c~sched-skip-updating-rqs-next_balance-under-null-sd
+++ a/kernel/sched.c
@@ -3020,6 +3020,7 @@ static inline void rebalance_domains(int
struct sched_domain *sd;
/* Earliest time when we have to do rebalance again */
unsigned long next_balance = jiffies + 60*HZ;
+ int update_next_balance = 0;
for_each_domain(cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
@@ -3056,8 +3057,10 @@ static inline void rebalance_domains(int
if (sd->flags & SD_SERIALIZE)
spin_unlock(&balancing);
out:
- if (time_after(next_balance, sd->last_balance + interval))
+ if (time_after(next_balance, sd->last_balance + interval)) {
next_balance = sd->last_balance + interval;
+ update_next_balance = 1;
+ }
/*
* Stop the load balance at this level. There is another
@@ -3067,7 +3070,14 @@ out:
if (!balance)
break;
}
- rq->next_balance = next_balance;
+
+ /*
+ * next_balance will be updated only when there is a need.
+ * When the cpu is attached to null domain for ex, it will not be
+ * updated.
+ */
+ if (likely(update_next_balance))
+ rq->next_balance = next_balance;
}
/*
_
Patches currently in -mm which might be from suresh.b.siddha@xxxxxxxxx are
origin.patch
intel-iommu-dmar-detection-and-parsing-logic.patch
intel-iommu-pci-generic-helper-function.patch
intel-iommu-clflush_cache_range-now-takes-size-param.patch
intel-iommu-iova-allocation-and-management-routines.patch
intel-iommu-intel-iommu-driver.patch
intel-iommu-avoid-memory-allocation-failures-in-dma-map-api-calls.patch
intel-iommu-intel-iommu-cmdline-option-forcedac.patch
intel-iommu-dmar-fault-handling-support.patch
intel-iommu-iommu-gfx-workaround.patch
intel-iommu-iommu-floppy-workaround.patch
intel-iommu-optimize-sg-map-unmap-calls.patch
-
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