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authorGregory Haskins <ghaskins@novell.com>2008-05-12 21:21:01 +0200
committerIngo Molnar <mingo@elte.hu>2008-06-06 15:19:28 +0200
commit6e0534f278199f1e3dd1049b9bc19a7a5b87ada1 (patch)
tree25f4da14ec32927742db9f599ac779b4e83d1763 /kernel/sched.c
parentf333fdc9098b71e2687e4e9b6349fcb352960d66 (diff)
downloadlwn-6e0534f278199f1e3dd1049b9bc19a7a5b87ada1.tar.gz
lwn-6e0534f278199f1e3dd1049b9bc19a7a5b87ada1.zip
sched: use a 2-d bitmap for searching lowest-pri CPU
The current code use a linear algorithm which causes scaling issues on larger SMP machines. This patch replaces that algorithm with a 2-dimensional bitmap to reduce latencies in the wake-up path. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index aa960b84b881..8a1257b65560 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -74,6 +74,8 @@
#include <asm/tlb.h>
#include <asm/irq_regs.h>
+#include "sched_cpupri.h"
+
/*
* Convert user-nice values [ -20 ... 0 ... 19 ]
* to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
@@ -450,6 +452,9 @@ struct root_domain {
*/
cpumask_t rto_mask;
atomic_t rto_count;
+#ifdef CONFIG_SMP
+ struct cpupri cpupri;
+#endif
};
/*
@@ -6392,6 +6397,8 @@ static void init_rootdomain(struct root_domain *rd)
cpus_clear(rd->span);
cpus_clear(rd->online);
+
+ cpupri_init(&rd->cpupri);
}
static void init_defrootdomain(void)