Messages in this thread Patch in this message | | | From | Suren Baghdasaryan <> | Date | Thu, 13 Oct 2022 09:10:59 -0700 | Subject | Re: [PATCH] sched/psi: Fix avgs_work re-arm in psi_avgs_work() |
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On Thu, Oct 13, 2022 at 8:52 AM Johannes Weiner <hannes@cmpxchg.org> wrote: > > On Thu, Oct 13, 2022 at 07:06:55PM +0800, Chengming Zhou wrote: > > Should I still need to copy groupc->tasks[] out for the current_cpu as you > > suggested before? > > It'd be my preference as well. This way the resched logic can be > consolidated into a single block of comment + code at the end of the > function.
Sounds good to me. If we are copying times in the retry loop then let's move the `reschedule =` decision out of that loop completely. At the end of get_recent_times we can do:
if (cpu == current_cpu) reschedule = tasks[NR_RUNNING] + tasks[NR_IOWAIT] + tasks[NR_MEMSTALL] > 1; else reschedule = *pchanged_states & (1 << PSI_NONIDLE);
> > > @@ -242,6 +242,8 @@ static void get_recent_times(struct psi_group *group, int cpu, > > u32 *pchanged_states) > > { > > struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu); > > + int current_cpu = raw_smp_processor_id(); > > + bool reschedule; > > u64 now, state_start; > > enum psi_states s; > > unsigned int seq; > > @@ -256,6 +258,10 @@ static void get_recent_times(struct psi_group *group, int cpu, > > memcpy(times, groupc->times, sizeof(groupc->times)); > > state_mask = groupc->state_mask; > > state_start = groupc->state_start; > > + if (cpu == current_cpu) > > + reschedule = groupc->tasks[NR_RUNNING] + > > + groupc->tasks[NR_IOWAIT] + > > + groupc->tasks[NR_MEMSTALL] > 1; > > } while (read_seqcount_retry(&groupc->seq, seq)); > > This also matches psi_show() and the poll worker. They don't currently > use the flag, but it's somewhat fragile and confusing. Add a test for > current_work() == &group->avgs_work?
Good point. (tasks[NR_RUNNING] + tasks[NR_IOWAIT] + tasks[NR_MEMSTALL] > 1) condition should also contain this check.
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