The patch titled
Subject: psi: track changed states
has been added to the -mm tree. Its filename is
psi-track-changed-states.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/psi-track-changed-states.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/psi-track-changed-states.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/kernel/sched/psi.c~psi-track-changed-states
+++ a/kernel/sched/psi.c
@@ -210,7 +210,8 @@ static bool test_state(unsigned int *tas
}
}
-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_
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_
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[
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
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
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_st
{
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_st
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
/* 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);
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
psi-introduce-state_mask-to-represent-stalled-psi-states.patch
psi-make-psi_enable-static.patch
psi-rename-psi-fields-in-preparation-for-psi-trigger-addition.patch
psi-rename-psi-fields-in-preparation-for-psi-trigger-addition-v6.patch
psi-split-update_stats-into-parts.patch
psi-track-changed-states.patch
refactor-header-includes-to-allow-kthreadh-inclusion-in-psi_typesh.patch
psi-introduce-psi-monitor.patch
