From: Wanpeng Li Date: Thu, 30 Oct 2014 22:39:32 +0000 (+0800) Subject: sched/deadline: Fix artificial overrun introduced by yield_task_dl() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=804968809c321066cca028d4cbd533a420f964bc;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git sched/deadline: Fix artificial overrun introduced by yield_task_dl() The yield semantic of deadline class is to reduce remaining runtime to zero, and then update_curr_dl() will stop it. However, comsumed bandwidth is reduced from the budget of yield task again even if it has already been set to zero which leads to artificial overrun. This patch fix it by make sure we don't steal some more time from the task that yielded in update_curr_dl(). Suggested-by: Juri Lelli Signed-off-by: Wanpeng Li Signed-off-by: Peter Zijlstra (Intel) Cc: Kirill Tkhai Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1414708776-124078-2-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 9d483e862e58..c047a94de273 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -628,7 +628,7 @@ static void update_curr_dl(struct rq *rq) sched_rt_avg_update(rq, delta_exec); - dl_se->runtime -= delta_exec; + dl_se->runtime -= dl_se->dl_yielded ? 0 : delta_exec; if (dl_runtime_exceeded(rq, dl_se)) { __dequeue_task_dl(rq, curr, 0); if (likely(start_dl_timer(dl_se, curr->dl.dl_boosted)))