On Fri, Jun 16, 2023 at 03:39:26PM +0800, Zqiang wrote: > The rcuscale.holdoff can be used to delay the start of rcu_scale_writer > kthread, however, if the rcuscale.holdoff is set and the timeout is greater > than the hung_task_timeout_secs, can trigger the hung-task timeout: > > runqemu kvm nographic slirp qemuparams="-smp 4 -m 2048M" > bootparams="rcuscale.shutdown=0 rcuscale.holdoff=300" > > [ 247.071753] INFO: task rcu_scale_write:59 blocked for more than 122 seconds. > [ 247.072529] Not tainted 6.4.0-rc1-00134-gb9ed6de8d4ff #7 > [ 247.073400] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 247.074331] task:rcu_scale_write state:D stack:30144 pid:59 ppid:2 flags:0x00004000 > [ 247.075346] Call Trace: > [ 247.075660] <TASK> > [ 247.075965] __schedule+0x635/0x1280 > [ 247.076448] ? __pfx___schedule+0x10/0x10 > [ 247.076967] ? schedule_timeout+0x2dc/0x4d0 > [ 247.077471] ? __pfx_lock_release+0x10/0x10 > [ 247.078018] ? enqueue_timer+0xe2/0x220 > [ 247.078522] schedule+0x84/0x120 > [ 247.078957] schedule_timeout+0x2e1/0x4d0 > [ 247.079447] ? __pfx_schedule_timeout+0x10/0x10 > [ 247.080032] ? __pfx_rcu_scale_writer+0x10/0x10 > [ 247.080591] ? __pfx_process_timeout+0x10/0x10 > [ 247.081163] ? __pfx_sched_set_fifo_low+0x10/0x10 > [ 247.081760] ? __pfx_rcu_scale_writer+0x10/0x10 > [ 247.082287] rcu_scale_writer+0x6b1/0x7f0 > [ 247.082773] ? mark_held_locks+0x29/0xa0 > [ 247.083252] ? __pfx_rcu_scale_writer+0x10/0x10 > [ 247.083865] ? __pfx_rcu_scale_writer+0x10/0x10 > [ 247.084412] kthread+0x179/0x1c0 > [ 247.084759] ? __pfx_kthread+0x10/0x10 > [ 247.085098] ret_from_fork+0x2c/0x50 > [ 247.085433] </TASK> > > This commit therefore replaces schedule_timeout_uninterruptible() with > schedule_timeout_idle(). > > Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx> Good catch, queued, thank you! Thanx, Paul > --- > kernel/rcu/rcuscale.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c > index a0eae1900708..ffdb30495e3c 100644 > --- a/kernel/rcu/rcuscale.c > +++ b/kernel/rcu/rcuscale.c > @@ -469,7 +469,7 @@ rcu_scale_writer(void *arg) > sched_set_fifo_low(current); > > if (holdoff) > - schedule_timeout_uninterruptible(holdoff * HZ); > + schedule_timeout_idle(holdoff * HZ); > > /* > * Wait until rcu_end_inkernel_boot() is called for normal GP tests > -- > 2.17.1 >
