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authorDietmar Eggemann <dietmar.eggemann@arm.com>2021-08-04 16:59:25 +0300
committerPeter Zijlstra <peterz@infradead.org>2021-08-06 15:25:24 +0300
commitb4da13aa28d4fd0071247b7b41c579ee8a86c81a (patch)
tree8bf5c0f3ab21a65da54e755b2005b95df253a7ba /kernel/sched/deadline.c
parent56498cfb045d7147cdcba33795d19429afcd1d00 (diff)
downloadlinux-b4da13aa28d4fd0071247b7b41c579ee8a86c81a.tar.xz
sched/deadline: Fix missing clock update in migrate_task_rq_dl()
A missing clock update is causing the following warning: rq->clock_update_flags < RQCF_ACT_SKIP WARNING: CPU: 112 PID: 2041 at kernel/sched/sched.h:1453 sub_running_bw.isra.0+0x190/0x1a0 ... CPU: 112 PID: 2041 Comm: sugov:112 Tainted: G W 5.14.0-rc1 #1 Hardware name: WIWYNN Mt.Jade Server System B81.030Z1.0007/Mt.Jade Motherboard, BIOS 1.6.20210526 (SCP: 1.06.20210526) 2021/05/26 ... Call trace: sub_running_bw.isra.0+0x190/0x1a0 migrate_task_rq_dl+0xf8/0x1e0 set_task_cpu+0xa8/0x1f0 try_to_wake_up+0x150/0x3d4 wake_up_q+0x64/0xc0 __up_write+0xd0/0x1c0 up_write+0x4c/0x2b0 cppc_set_perf+0x120/0x2d0 cppc_cpufreq_set_target+0xe0/0x1a4 [cppc_cpufreq] __cpufreq_driver_target+0x74/0x140 sugov_work+0x64/0x80 kthread_worker_fn+0xe0/0x230 kthread+0x138/0x140 ret_from_fork+0x10/0x18 The task causing this is the `cppc_fie` DL task introduced by commit 1eb5dde674f5 ("cpufreq: CPPC: Add support for frequency invariance"). With CONFIG_ACPI_CPPC_CPUFREQ_FIE=y and schedutil cpufreq governor on slow-switching system (like on this Ampere Altra WIWYNN Mt. Jade Arm Server): DL task `curr=sugov:112` lets `p=cppc_fie` migrate and since the latter is in `non_contending` state, migrate_task_rq_dl() calls sub_running_bw()->__sub_running_bw()->cpufreq_update_util()-> rq_clock()->assert_clock_updated() on p. Fix this by updating the clock for a non_contending task in migrate_task_rq_dl() before calling sub_running_bw(). Reported-by: Bruno Goncalves <bgoncalv@redhat.com> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org> Acked-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lore.kernel.org/r/20210804135925.3734605-1-dietmar.eggemann@arm.com
Diffstat (limited to 'kernel/sched/deadline.c')
-rw-r--r--kernel/sched/deadline.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 5cafc642e647..e94314633b39 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1733,6 +1733,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused
*/
raw_spin_rq_lock(rq);
if (p->dl.dl_non_contending) {
+ update_rq_clock(rq);
sub_running_bw(&p->dl, &rq->dl);
p->dl.dl_non_contending = 0;
/*