From: Suren Baghdasaryan surenb@google.com
mainline inclusion from mainline-v5.4 commit 7fc70a3999366560ad1d4f2389a78360300c2c6a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I47QS2 CVE: NA
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Split update_stats into collect_percpu_times and update_averages for collect_percpu_times to be reused later inside psi monitor.
Link: http://lkml.kernel.org/r/20190319235619.260832-5-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 Signed-off-by: Liu Xinpeng liuxp11@chinatelecom.cn # openEuler_contributor Signed-off-by: Ctyun Kernel ctyuncommiter01@chinatelecom.cn # openEuler_contributor Reviewed-by: Chen Hui judy.chenhui@huawei.com --- kernel/sched/psi.c | 57 ++++++++++++++++++++++++++++++++---------------------- 1 file changed, 34 insertions(+), 23 deletions(-)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 4fb4d991..ace5ed9 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[3], int missed_periods, avg[2] = calc_load(avg[2], EXP_300s, pct); }
-static bool update_stats(struct psi_group *group) +static bool collect_percpu_times(struct psi_group *group) { u64 deltas[NR_PSI_STATES - 1] = { 0, }; - unsigned long missed_periods = 0; unsigned long nonidle_total = 0; - u64 now, expires, period; int cpu; int s;
- mutex_lock(&group->avgs_lock); - /* * Collect the per-cpu time buckets and average them into a * single time sample that is normalized to wallclock time. @@ -317,11 +313,18 @@ static bool update_stats(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; +} + +static u64 update_averages(struct psi_group *group, u64 now) +{ + unsigned long missed_periods = 0; + u64 expires, period; + u64 avg_next_update; + int s; + /* avgX= */ - now = sched_clock(); expires = group->avg_next_update; - if (now < expires) - goto out; if (now - expires >= psi_period) missed_periods = div_u64(now - expires, psi_period);
@@ -332,7 +335,7 @@ static bool update_stats(struct psi_group *group) * But the deltas we sample out of the per-cpu buckets above * are based on the actual time elapsing between clock ticks. */ - group->avg_next_update = expires + ((1 + missed_periods) * psi_period); + avg_next_update = expires + ((1 + missed_periods) * psi_period); period = now - (group->avg_last_update + (missed_periods * psi_period)); group->avg_last_update = now;
@@ -362,9 +365,8 @@ static bool update_stats(struct psi_group *group) group->avg_total[s] += sample; calc_avgs(group->avg[s], missed_periods, sample, period); } -out: - mutex_unlock(&group->avgs_lock); - return nonidle_total; + + return avg_next_update; }
static void psi_avgs_work(struct work_struct *work) @@ -372,10 +374,16 @@ static void psi_avgs_work(struct work_struct *work) struct delayed_work *dwork; struct psi_group *group; bool nonidle; + u64 now;
dwork = to_delayed_work(work); group = container_of(dwork, struct psi_group, avgs_work);
+ mutex_lock(&group->avgs_lock); + + now = sched_clock(); + + nonidle = collect_percpu_times(group); /* * If there is task activity, periodically fold the per-cpu * times and feed samples into the running averages. If things @@ -383,19 +391,15 @@ static void psi_avgs_work(struct work_struct *work) * Once restarted, we'll catch up the running averages in one * go - see calc_avgs() and missed_periods. */ - - nonidle = update_stats(group); + if (now >= group->avg_next_update) + group->avg_next_update = update_averages(group, now);
if (nonidle) { - unsigned long delay = 0; - u64 now; - - now = sched_clock(); - if (group->avg_next_update > now) - delay = nsecs_to_jiffies( - group->avg_next_update - now) + 1; - schedule_delayed_work(dwork, delay); + schedule_delayed_work(dwork, nsecs_to_jiffies( + group->avg_next_update - now) + 1); } + + mutex_unlock(&group->avgs_lock); }
static void record_times(struct psi_group_cpu *groupc, int cpu, @@ -707,11 +711,18 @@ void cgroup_move_task(struct task_struct *task, struct css_set *to) int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res) { int full; + u64 now;
if (static_branch_likely(&psi_disabled)) return -EOPNOTSUPP;
- update_stats(group); + /* Update averages before reporting them */ + mutex_lock(&group->avgs_lock); + now = sched_clock(); + collect_percpu_times(group); + if (now >= group->avg_next_update) + group->avg_next_update = update_averages(group, now); + mutex_unlock(&group->avgs_lock);
for (full = 0; full < 2 - (res == PSI_CPU); full++) { unsigned long avg[3];