Do the placement thing using SD flags
XXX: consider degenerate bits
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Dinakar Guniguntala <dino@xxxxxxxxxx>
---
include/linux/sched.h | 29 +++++++++++++++--------------
kernel/sched.c | 14 +++++++++++++-
2 files changed, 28 insertions(+), 15 deletions(-)
Index: linux-2.6.31.4-rt14/include/linux/sched.h
===================================================================
--- linux-2.6.31.4-rt14.orig/include/linux/sched.h 2009-10-16 09:15:18.000000000 -0400
+++ linux-2.6.31.4-rt14/include/linux/sched.h 2009-10-16 09:15:30.000000000 -0400
@@ -843,18 +843,19 @@
#define SCHED_LOAD_SCALE_FUZZ SCHED_LOAD_SCALE
#ifdef CONFIG_SMP
-#define SD_LOAD_BALANCE 1 /* Do load balancing on this domain. */
-#define SD_BALANCE_NEWIDLE 2 /* Balance when about to become idle */
-#define SD_BALANCE_EXEC 4 /* Balance on exec */
-#define SD_BALANCE_FORK 8 /* Balance on fork, clone */
-#define SD_WAKE_IDLE 16 /* Wake to idle CPU on task wakeup */
-#define SD_WAKE_AFFINE 32 /* Wake task to waking CPU */
-#define SD_WAKE_BALANCE 64 /* Perform balancing at task wakeup */
-#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 SD_WAKE_IDLE_FAR 2048 /* Gain latency sacrificing cache hit */
+#define SD_LOAD_BALANCE 0x0001 /* Do load balancing on this domain. */
+#define SD_BALANCE_NEWIDLE 0x0002 /* Balance when about to become idle */
+#define SD_BALANCE_EXEC 0x0004 /* Balance on exec */
+#define SD_BALANCE_FORK 0x0008 /* Balance on fork, clone */
+#define SD_WAKE_IDLE 0x0010 /* Wake to idle CPU on task wakeup */
+#define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU */
+#define SD_WAKE_BALANCE 0x0040 /* Perform balancing at task wakeup */
+#define SD_SHARE_CPUPOWER 0x0080 /* Domain members share cpu power */
+#define SD_POWERSAVINGS_BALANCE 0x0100 /* Balance for power savings */
+#define SD_SHARE_PKG_RESOURCES 0x0200 /* Domain members share cpu pkg resources */
+#define SD_SERIALIZE 0x0400 /* Only a single load balancing instance */
+#define SD_WAKE_IDLE_FAR 0x0800 /* Gain latency sacrificing cache hit */
+#define SD_PREFER_SIBLING 0x1000 /* Prefer to place tasks in a sibling domain */
enum powersavings_balance_level {
POWERSAVINGS_BALANCE_NONE = 0, /* No power saving load balance */
@@ -874,7 +875,7 @@
if (sched_smt_power_savings)
return SD_POWERSAVINGS_BALANCE;
- return 0;
+ return SD_PREFER_SIBLING;
}
static inline int sd_balance_for_package_power(void)
@@ -882,7 +883,7 @@
if (sched_mc_power_savings | sched_smt_power_savings)
return SD_POWERSAVINGS_BALANCE;
- return 0;
+ return SD_PREFER_SIBLING;
}
/*
Index: linux-2.6.31.4-rt14/kernel/sched.c
===================================================================
--- linux-2.6.31.4-rt14.orig/kernel/sched.c 2009-10-16 09:15:18.000000000 -0400
+++ linux-2.6.31.4-rt14/kernel/sched.c 2009-10-16 09:15:30.000000000 -0400
@@ -3892,9 +3892,13 @@
const struct cpumask *cpus, int *balance,
struct sd_lb_stats *sds)
{
+ struct sched_domain *child = sd->child;
struct sched_group *group = sd->groups;
struct sg_lb_stats sgs;
- int load_idx;
+ int load_idx, prefer_sibling = 0;
+
+ if (child && child->flags & SD_PREFER_SIBLING)
+ prefer_sibling = 1;
init_sd_power_savings_stats(sd, sds, idle);
load_idx = get_sd_load_idx(sd, idle);
@@ -3914,6 +3918,14 @@
sds->total_load += sgs.group_load;
sds->total_pwr += group->__cpu_power;
+ /*
+ * In case the child domain prefers tasks go to siblings
+ * first, lower the group capacity to one so that we'll try
+ * and move all the excess tasks away.
+ */
+ if (prefer_sibling)
+ sgs.group_capacity = 1;
+
if (local_group) {
sds->this_load = sgs.avg_load;
sds->this = group;
--
--
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