From 943d355d7feef380e15a95892be3dff1095ef54b Mon Sep 17 00:00:00 2001 From: Rohit Jain Date: Wed, 9 May 2018 09:39:48 -0700 Subject: sched/core: Distinguish between idle_cpu() calls based on desired effect, introduce available_idle_cpu() In the following commit: 247f2f6f3c70 ("sched/core: Don't schedule threads on pre-empted vCPUs") ... we distinguish between idle_cpu() when the vCPU is not running for scheduling threads. However, the idle_cpu() function is used in other places for actually checking whether the state of the CPU is idle or not. Hence split the use of that function based on the desired return value, by introducing the available_idle_cpu() function. This fixes a (slight) regression in that initial vCPU commit, because some code paths (like the load-balancer) don't care and shouldn't care if the vCPU is preempted or not, they just want to know if there's any tasks on the CPU. Signed-off-by: Rohit Jain Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dhaval.giani@oracle.com Cc: linux-kernel@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: steven.sistare@oracle.com Cc: subhra.mazumdar@oracle.com Link: http://lkml.kernel.org/r/1525883988-10356-1-git-send-email-rohit.k.jain@oracle.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index c2413703f45d..959a8588e365 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1504,6 +1504,7 @@ static inline int task_nice(const struct task_struct *p) extern int can_nice(const struct task_struct *p, const int nice); extern int task_curr(const struct task_struct *p); extern int idle_cpu(int cpu); +extern int available_idle_cpu(int cpu); extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *); extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *); extern int sched_setattr(struct task_struct *, const struct sched_attr *); -- cgit v1.2.3