[PATCH] sched: add option to serialize load balancing
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.
[akpm@osdl.org: build fix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Peter Williams <pwil3058@bigpond.net.au>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1208fea..ea92e5c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -648,6 +648,7 @@
#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 --git a/include/linux/topology.h b/include/linux/topology.h
index b93bb6c..6c5a6e6 100644
--- a/include/linux/topology.h
+++ b/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, \