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| author | Gregory Haskins <ghaskins@novell.com> | 2008-05-12 21:21:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-06-06 15:19:28 +0200 |
| commit | 6e0534f278199f1e3dd1049b9bc19a7a5b87ada1 (patch) | |
| tree | 25f4da14ec32927742db9f599ac779b4e83d1763 /kernel/sched_cpupri.h | |
| parent | f333fdc9098b71e2687e4e9b6349fcb352960d66 (diff) | |
| download | kernel_samsung_smdk4412-6e0534f278199f1e3dd1049b9bc19a7a5b87ada1.tar.gz kernel_samsung_smdk4412-6e0534f278199f1e3dd1049b9bc19a7a5b87ada1.tar.bz2 kernel_samsung_smdk4412-6e0534f278199f1e3dd1049b9bc19a7a5b87ada1.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_cpupri.h')
| -rw-r--r-- | kernel/sched_cpupri.h | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/kernel/sched_cpupri.h b/kernel/sched_cpupri.h new file mode 100644 index 00000000000..0b6a3d110fa --- /dev/null +++ b/kernel/sched_cpupri.h @@ -0,0 +1,36 @@ +#ifndef _LINUX_CPUPRI_H +#define _LINUX_CPUPRI_H + +#include <linux/sched.h> + +#define CPUPRI_NR_PRIORITIES 2+MAX_RT_PRIO +#define CPUPRI_NR_PRI_WORDS CPUPRI_NR_PRIORITIES/BITS_PER_LONG + +#define CPUPRI_INVALID -1 +#define CPUPRI_IDLE 0 +#define CPUPRI_NORMAL 1 +/* values 2-101 are RT priorities 0-99 */ + +struct cpupri_vec { + spinlock_t lock; + int count; + cpumask_t mask; +}; + +struct cpupri { + struct cpupri_vec pri_to_cpu[CPUPRI_NR_PRIORITIES]; + long pri_active[CPUPRI_NR_PRI_WORDS]; + int cpu_to_pri[NR_CPUS]; +}; + +#ifdef CONFIG_SMP +int cpupri_find(struct cpupri *cp, + struct task_struct *p, cpumask_t *lowest_mask); +void cpupri_set(struct cpupri *cp, int cpu, int pri); +void cpupri_init(struct cpupri *cp); +#else +#define cpupri_set(cp, cpu, pri) do { } while (0) +#define cpupri_init() do { } while (0) +#endif + +#endif /* _LINUX_CPUPRI_H */ |