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author | Suren Baghdasaryan <surenb@google.com> | 2019-05-15 00:41:09 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-15 04:52:48 +0200 |
commit | 333f3017c5a893b000b2b4a3529814ce93fa83d7 (patch) | |
tree | db1b3f80235376b7a04115ae04212be83106fbb9 /kernel/sched | |
parent | psi: split update_stats into parts (diff) | |
download | linux-333f3017c5a893b000b2b4a3529814ce93fa83d7.tar.xz linux-333f3017c5a893b000b2b4a3529814ce93fa83d7.zip |
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>
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/psi.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index ace5ed97b186..1b99eeffaa25 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -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); |