From d02c7a8cf208eb80a3ccbff40a6bebe8902af35a Mon Sep 17 00:00:00 2001 From: Con Kolivas Date: Thu, 26 Jul 2007 13:40:43 +0200 Subject: [PATCH] [PATCH] sched: add above_background_load() function Add an above_background_load() function which can be used by other subsystems to detect if there is anything besides niced tasks running. Place it in sched.h to allow it to be compiled out if not used. Unused for now, but it is a useful hint to the IO scheduler and to swap-prefetch. Signed-off-by: Con Kolivas Cc: Peter Williams Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- include/linux/sched.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 7a4de8768748..2e490271acf6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -786,6 +786,22 @@ extern int partition_sched_domains(cpumask_t *partition1, #endif /* CONFIG_SMP */ +/* + * A runqueue laden with a single nice 0 task scores a weighted_cpuload of + * SCHED_LOAD_SCALE. This function returns 1 if any cpu is laden with a + * task of nice 0 or enough lower priority tasks to bring up the + * weighted_cpuload + */ +static inline int above_background_load(void) +{ + unsigned long cpu; + + for_each_online_cpu(cpu) { + if (weighted_cpuload(cpu) >= SCHED_LOAD_SCALE) + return 1; + } + return 0; +} struct io_context; /* See blkdev.h */ struct cpuset; -- 2.34.1