Messages in this thread | | | From | Yafang Shao <> | Date | Sat, 6 Nov 2021 15:40:53 +0800 | Subject | Re: [RFC PATCH 4/4] sched/core: Do numa balance in cfs_migration |
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On Sat, Nov 6, 2021 at 1:02 AM Valentin Schneider <valentin.schneider@arm.com> wrote: > > On 04/11/21 14:57, Yafang Shao wrote: > > Similar to active load balance, the numa balance work is also applied to > > cfs tasks only and it should't preempt other FIFO tasks. We'd better assign > > cfs_migration to the numa balance as well. > > > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > Cc: Valentin Schneider <valentin.schneider@arm.com> > > Cc: Vincent Guittot <vincent.guittot@linaro.org> > > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > > --- > > kernel/sched/core.c | 2 +- > > kernel/sched/fair.c | 13 +++++++++++++ > > kernel/sched/sched.h | 2 ++ > > 3 files changed, 16 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 9cb81ef8acc8..4a37b06715f4 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -8724,7 +8724,7 @@ int migrate_task_to(struct task_struct *p, int target_cpu) > > /* TODO: This is not properly updating schedstats */ > > > > trace_sched_move_numa(p, curr_cpu, target_cpu); > > - return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); > > + return wakeup_cfs_migrater(curr_cpu, migration_cpu_stop, &arg); > > So that one I find really icky - migration_cpu_stop() really is meant to be > run from a CPU stopper (cf. cpu_stop suffix). IMO this is the opportunity > to make NUMA balancing reuse the logic for CFS active balance here, but per > previous email I'd say it could be done as a second step. >
Sure.
> > } > > > > /* > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 932f63baeb82..b7a155e05c98 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -11960,6 +11960,19 @@ static void wakeup_cfs_migrater_nowait(unsigned int cpu, cpu_stop_fn_t fn, void > > cfs_migration_queue_work(cpu, work_buf); > > } > > > > +bool wakeup_cfs_migrater(unsigned int cpu, cpu_stop_fn_t fn, void *arg) > > +{ > > + struct cpu_stop_done done; > > + struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done, .caller = _RET_IP_ }; > > + > > + cpu_stop_init_done(&done, 1); > > + cfs_migration_queue_work(cpu, &work); > > + cond_resched(); > > + wait_for_completion(&done.completion); > > + > > + return done.ret; > > +} > > + > > static int cfs_migration_should_run(unsigned int cpu) > > { > > struct cfs_migrater *migrater = &per_cpu(cfs_migrater, cpu); > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > > index a00fc7057d97..7b242c18a6d8 100644 > > --- a/kernel/sched/sched.h > > +++ b/kernel/sched/sched.h > > @@ -3055,6 +3055,8 @@ static inline bool is_per_cpu_kthread(struct task_struct *p) > > > > return true; > > } > > + > > +bool wakeup_cfs_migrater(unsigned int cpu, cpu_stop_fn_t fn, void *arg); > > #endif > > > > extern void swake_up_all_locked(struct swait_queue_head *q); > > -- > > 2.17.1
-- Thanks Yafang
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