From a59f4e079d19464eebb9b06513a1d4f55fdae5ba Mon Sep 17 00:00:00 2001 From: Zhu Yanhai Date: Tue, 8 Jan 2013 12:56:52 +0800 Subject: [PATCH] sched: Fix the broken sched_rr_get_interval() The caller of sched_sliced() should pass se.cfs_rq and se as the arguments, however in sched_rr_get_interval() we gave it rq.cfs_rq and se, which made the following computation obviously wrong. The change was introduced by commit: 77034937dc45 sched: fix crash in sys_sched_rr_get_interval() ... 5 years ago, while it had been the correct 'cfs_rq_of' before the commit. The change seems to be irrelevant to the commit msg, which was to return a 0 timeslice for tasks that are on an idle runqueue. So I believe that was just a plain typo. Signed-off-by: Zhu Yanhai Cc: Peter Zijlstra Cc: Paul Turner Cc: Thomas Gleixner Cc: Steven Rostedt Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1357621012-15039-1-git-send-email-gaoyang.zyh@taobao.com [ Since this is an ABI and an old bug, we'll test this via a slow upstream route, to hopefully discover any app breakage. ] Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5eea8707234..a7a19ffc3b7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6101,7 +6101,7 @@ static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task * idle runqueue: */ if (rq->cfs.load.weight) - rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); + rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se)); return rr_interval; } -- 2.20.1