Messages in this thread | | | Date | Sat, 29 Apr 2017 11:06:38 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [patch] timer: Fix timers_update_migration(), and call it in tmigr_init() |
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On Sat, Apr 29, 2017 at 06:06:40PM +0200, Mike Galbraith wrote: > Note: there is more. With this applied, my desktop box will no longer > reproduce when booted to init 3 with nowatchdog on the command line. > My 8 socket DL980 OTOH still will, though it takes longer, and is > seemingly no longer interested in following up with a permanent RCU > stall after the tsc clocksource is killed, as it does in virgin source. > > --- > > timers_update_migration() is called by tick_nohz_activate() before > the late initcall tmigr_init() sets tmigr_enabled to true, resulting > in it updating neither timer_base.nohz_active nor .migration_enabled, > meaning we'll not kick an idling cpu in add_timer_on(). > > Remove redundant loop avoidance such that tick_nohz_activate() updates > timer_bases[].nohz_active as intended, and call it in tmigr_init() to > update timer_bases[].migration_enabled. > > Signed-off-by: Mike Galbraith <efault@gmx.de> > Fixes: ec2206b91d43 timer: Implement the hierarchical pull model
If someone will either repost a fresh series or point me at exactly the set of patches to use, I will run it through rcutorture again.
Thanx, Paul
> --- > kernel/time/timer.c | 4 ---- > kernel/time/timer_migration.c | 1 + > 2 files changed, 1 insertion(+), 4 deletions(-) > > --- a/kernel/time/timer.c > +++ b/kernel/time/timer.c > @@ -224,10 +224,6 @@ void timers_update_migration(bool update > bool on = sysctl_timer_migration && tick_nohz_active && tmigr_enabled; > unsigned int cpu; > > - /* Avoid the loop, if nothing to update */ > - if (this_cpu_read(timer_bases[BASE_GLOBAL].migration_enabled) == on) > - return; > - > for_each_possible_cpu(cpu) { > per_cpu(timer_bases[BASE_LOCAL].migration_enabled, cpu) = on; > per_cpu(timer_bases[BASE_GLOBAL].migration_enabled, cpu) = on; > --- a/kernel/time/timer_migration.c > +++ b/kernel/time/timer_migration.c > @@ -649,6 +649,7 @@ static int __init tmigr_init(void) > goto hp_err; > > tmigr_enabled = true; > + timers_update_migration(false); > pr_info("Timer migration: %d hierarchy levels\n", tmigr_hierarchy_levels); > return 0; > >
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