The patch titled
sched: add option to serialize load balancing
has been added to the -mm tree. Its filename is
sched-add-option-to-serialize-load-balancing.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: sched: add option to serialize load balancing
From: Christoph Lameter <clameter@xxxxxxx>
Large sched domains can be very expensive to scan. Add an option SD_SERIALIZE
to the sched domain flags. If that flag is set then we make sure that no
other such domain is being balanced.
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Cc: Peter Williams <pwil3058@xxxxxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Christoph Lameter <clameter@xxxxxxx>
Cc: "Siddha, Suresh B" <suresh.b.siddha@xxxxxxxxx>
Cc: "Chen, Kenneth W" <kenneth.w.chen@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-i386/topology.h | 1 +
include/asm-ia64/topology.h | 1 +
include/asm-powerpc/topology.h | 1 +
include/asm-x86_64/topology.h | 1 +
include/linux/sched.h | 1 +
include/linux/topology.h | 3 ++-
kernel/sched.c | 10 ++++++++++
7 files changed, 17 insertions(+), 1 deletion(-)
diff -puN include/asm-i386/topology.h~sched-add-option-to-serialize-load-balancing include/asm-i386/topology.h
--- a/include/asm-i386/topology.h~sched-add-option-to-serialize-load-balancing
+++ a/include/asm-i386/topology.h
@@ -89,6 +89,7 @@ static inline int node_to_first_cpu(int
.flags = SD_LOAD_BALANCE \
| SD_BALANCE_EXEC \
| SD_BALANCE_FORK \
+ | SD_SERIALIZE \
| SD_WAKE_BALANCE, \
.last_balance = jiffies, \
.balance_interval = 1, \
diff -puN include/asm-ia64/topology.h~sched-add-option-to-serialize-load-balancing include/asm-ia64/topology.h
--- a/include/asm-ia64/topology.h~sched-add-option-to-serialize-load-balancing
+++ a/include/asm-ia64/topology.h
@@ -101,6 +101,7 @@ void build_cpu_to_node_map(void);
.flags = SD_LOAD_BALANCE \
| SD_BALANCE_EXEC \
| SD_BALANCE_FORK \
+ | SD_SERIALIZE \
| SD_WAKE_BALANCE, \
.last_balance = jiffies, \
.balance_interval = 64, \
diff -puN include/asm-powerpc/topology.h~sched-add-option-to-serialize-load-balancing include/asm-powerpc/topology.h
--- a/include/asm-powerpc/topology.h~sched-add-option-to-serialize-load-balancing
+++ a/include/asm-powerpc/topology.h
@@ -59,6 +59,7 @@ extern int pcibus_to_node(struct pci_bus
| SD_BALANCE_EXEC \
| SD_BALANCE_NEWIDLE \
| SD_WAKE_IDLE \
+ | SD_SERIALIZE \
| SD_WAKE_BALANCE, \
.last_balance = jiffies, \
.balance_interval = 1, \
diff -puN include/asm-x86_64/topology.h~sched-add-option-to-serialize-load-balancing include/asm-x86_64/topology.h
--- a/include/asm-x86_64/topology.h~sched-add-option-to-serialize-load-balancing
+++ a/include/asm-x86_64/topology.h
@@ -47,6 +47,7 @@ extern int __node_distance(int, int);
.flags = SD_LOAD_BALANCE \
| SD_BALANCE_FORK \
| SD_BALANCE_EXEC \
+ | SD_SERIALIZE \
| SD_WAKE_BALANCE, \
.last_balance = jiffies, \
.balance_interval = 1, \
diff -puN include/linux/sched.h~sched-add-option-to-serialize-load-balancing include/linux/sched.h
--- a/include/linux/sched.h~sched-add-option-to-serialize-load-balancing
+++ a/include/linux/sched.h
@@ -646,6 +646,7 @@ enum idle_type
#define SD_SHARE_CPUPOWER 128 /* Domain members share cpu power */
#define SD_POWERSAVINGS_BALANCE 256 /* Balance for power savings */
#define SD_SHARE_PKG_RESOURCES 512 /* Domain members share cpu pkg resources */
+#define SD_SERIALIZE 1024 /* Only a single load balancing instance */
#define BALANCE_FOR_MC_POWER \
(sched_smt_power_savings ? SD_POWERSAVINGS_BALANCE : 0)
diff -puN include/linux/topology.h~sched-add-option-to-serialize-load-balancing include/linux/topology.h
--- a/include/linux/topology.h~sched-add-option-to-serialize-load-balancing
+++ a/include/linux/topology.h
@@ -194,7 +194,8 @@
.wake_idx = 0, /* unused */ \
.forkexec_idx = 0, /* unused */ \
.per_cpu_gain = 100, \
- .flags = SD_LOAD_BALANCE, \
+ .flags = SD_LOAD_BALANCE \
+ | SD_SERIALIZE, \
.last_balance = jiffies, \
.balance_interval = 64, \
.nr_balance_failed = 0, \
diff -puN kernel/sched.c~sched-add-option-to-serialize-load-balancing kernel/sched.c
--- a/kernel/sched.c~sched-add-option-to-serialize-load-balancing
+++ a/kernel/sched.c
@@ -2880,6 +2880,7 @@ static void update_load(struct rq *this_
*
* Balancing parameters are set up in arch_init_sched_domains.
*/
+static spinlock_t balancing;
static void run_rebalance_domains(struct softirq_action *h)
{
@@ -2909,6 +2910,11 @@ static void run_rebalance_domains(struct
if (unlikely(!interval))
interval = 1;
+ if (sd->flags & SD_SERIALIZE) {
+ if (!spin_trylock(&balancing))
+ goto out;
+ }
+
if (time_after_eq(jiffies, sd->last_balance + interval)) {
if (load_balance(this_cpu, this_rq, sd, idle)) {
/*
@@ -2920,6 +2926,9 @@ static void run_rebalance_domains(struct
}
sd->last_balance = jiffies;
}
+ if (sd->flags & SD_SERIALIZE)
+ spin_unlock(&balancing);
+out:
if (time_after(next_balance, sd->last_balance + interval))
next_balance = sd->last_balance + interval;
}
@@ -6873,6 +6882,7 @@ void __init sched_init(void)
#ifdef CONFIG_RT_MUTEXES
plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
+ spin_lock_init(&balancing);
#endif
/*
_
Patches currently in -mm which might be from clameter@xxxxxxx are
memory-page-alloc-minor-cleanups.patch
memory-page-alloc-minor-cleanups-fix.patch
get-rid-of-zone_table.patch
deal-with-cases-of-zone_dma-meaning-the-first-zone.patch
get-rid-of-zone_table-fix-3.patch
introduce-config_zone_dma.patch
optional-zone_dma-in-the-vm.patch
optional-zone_dma-in-the-vm-no-gfp_dma-check-in-the-slab-if-no-config_zone_dma-is-set.patch
optional-zone_dma-in-the-vm-no-gfp_dma-check-in-the-slab-if-no-config_zone_dma-is-set-reduce-config_zone_dma-ifdefs.patch
optional-zone_dma-for-ia64.patch
remove-zone_dma-remains-from-parisc.patch
remove-zone_dma-remains-from-sh-sh64.patch
set-config_zone_dma-for-arches-with-generic_isa_dma.patch
zoneid-fix-up-calculations-for-zoneid_pgshift.patch
radix-tree-rcu-lockless-readside.patch
sched-domain-move-sched-group-allocations-to-percpu-area.patch
sched-avoid-taking-rq-lock-in-wake_priority_sleeper.patch
sched-remove-staggering-of-load-balancing.patch
sched-disable-interrupts-for-locking-in-load_balance.patch
sched-extract-load-calculation-from-rebalance_tick.patch
sched-move-idle-status-calculation-into-rebalance_tick.patch
sched-use-softirq-for-load-balancing.patch
sched-call-tasklet-less-frequently.patch
sched-add-option-to-serialize-load-balancing.patch
mm-only-sched-add-a-few-scheduler-event-counters.patch
zvc-support-nr_slab_reclaimable--nr_slab_unreclaimable-swap_prefetch.patch
reduce-max_nr_zones-swap_prefetch-remove-incorrect-use-of-zone_highmem.patch
numa-add-zone_to_nid-function-swap_prefetch.patch
readahead-state-based-method-aging-accounting.patch
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