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psi: track changed states 

Introduce changed_states parameter into collect_percpu_times to track
the states changed since the last update.

This will be needed to detect whether polled states activated in the
monitor patch.

Link: http://lkml.kernel.org/r/20190319235619.260832-6-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.2
Suren Baghdasaryan 2019-05-14 15:41:09 -07:00 committed by Linus Torvalds
parent 7fc70a3999
commit 333f3017c5
1 changed files with 18 additions and 6 deletions
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24
kernel/sched/psi.c
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@ -210,7 +210,8 @@ static bool test_state(unsigned int *tasks, enum psi_states state)
}
}
static void get_recent_times(struct psi_group *group, int cpu, u32 *times)
static void get_recent_times(struct psi_group *group, int cpu, u32 *times,
u32 *pchanged_states)
{
struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu);
u64 now, state_start;
@ -218,6 +219,8 @@ static void get_recent_times(struct psi_group *group, int cpu, u32 *times)
unsigned int seq;
u32 state_mask;
*pchanged_states = 0;
/* Snapshot a coherent view of the CPU state */
do {
seq = read_seqcount_begin(&groupc->seq);
@ -246,6 +249,8 @@ static void get_recent_times(struct psi_group *group, int cpu, u32 *times)
groupc->times_prev[s] = times[s];
times[s] = delta;
if (delta)
*pchanged_states |= (1 << s);
}
}
@ -269,10 +274,11 @@ static void calc_avgs(unsigned long avg[3], int missed_periods,
avg[2] = calc_load(avg[2], EXP_300s, pct);
}
static bool collect_percpu_times(struct psi_group *group)
static void collect_percpu_times(struct psi_group *group, u32 *pchanged_states)
{
u64 deltas[NR_PSI_STATES - 1] = { 0, };
unsigned long nonidle_total = 0;
u32 changed_states = 0;
int cpu;
int s;
@ -287,8 +293,11 @@ static bool collect_percpu_times(struct psi_group *group)
for_each_possible_cpu(cpu) {
u32 times[NR_PSI_STATES];
u32 nonidle;
u32 cpu_changed_states;
get_recent_times(group, cpu, times);
get_recent_times(group, cpu, times,
&cpu_changed_states);
changed_states |= cpu_changed_states;
nonidle = nsecs_to_jiffies(times[PSI_NONIDLE]);
nonidle_total += nonidle;
@ -313,7 +322,8 @@ static bool collect_percpu_times(struct psi_group *group)
for (s = 0; s < NR_PSI_STATES - 1; s++)
group->total[s] += div_u64(deltas[s], max(nonidle_total, 1UL));
return nonidle_total;
if (pchanged_states)
*pchanged_states = changed_states;
}
static u64 update_averages(struct psi_group *group, u64 now)
@ -373,6 +383,7 @@ static void psi_avgs_work(struct work_struct *work)
{
struct delayed_work *dwork;
struct psi_group *group;
u32 changed_states;
bool nonidle;
u64 now;
@ -383,7 +394,8 @@ static void psi_avgs_work(struct work_struct *work)
now = sched_clock();
nonidle = collect_percpu_times(group);
collect_percpu_times(group, &changed_states);
nonidle = changed_states & (1 << PSI_NONIDLE);
/*
* If there is task activity, periodically fold the per-cpu
* times and feed samples into the running averages. If things
@ -719,7 +731,7 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
/* Update averages before reporting them */
mutex_lock(&group->avgs_lock);
now = sched_clock();
collect_percpu_times(group);
collect_percpu_times(group, NULL);
if (now >= group->avg_next_update)
group->avg_next_update = update_averages(group, now);
mutex_unlock(&group->avgs_lock);