wake_up_interruptible(&group->poll_wait);
}
-static void record_times(struct psi_group_cpu *groupc, int cpu,
- bool memstall_tick)
+static void record_times(struct psi_group_cpu *groupc, int cpu)
{
u32 delta;
u64 now;
groupc->times[PSI_MEM_SOME] += delta;
if (groupc->state_mask & (1 << PSI_MEM_FULL))
groupc->times[PSI_MEM_FULL] += delta;
- else if (memstall_tick) {
- u32 sample;
- /*
- * Since we care about lost potential, a
- * memstall is FULL when there are no other
- * working tasks, but also when the CPU is
- * actively reclaiming and nothing productive
- * could run even if it were runnable.
- *
- * When the timer tick sees a reclaiming CPU,
- * regardless of runnable tasks, sample a FULL
- * tick (or less if it hasn't been a full tick
- * since the last state change).
- */
- sample = min(delta, (u32)jiffies_to_nsecs(1));
- groupc->times[PSI_MEM_FULL] += sample;
- }
}
if (groupc->state_mask & (1 << PSI_CPU_SOME)) {
*/
write_seqcount_begin(&groupc->seq);
- record_times(groupc, cpu, false);
+ record_times(groupc, cpu);
for (t = 0, m = clear; m; m &= ~(1 << t), t++) {
if (!(m & (1 << t)))
if (test_state(groupc->tasks, s))
state_mask |= (1 << s);
}
+
+ /*
+ * Since we care about lost potential, a memstall is FULL
+ * when there are no other working tasks, but also when
+ * the CPU is actively reclaiming and nothing productive
+ * could run even if it were runnable. So when the current
+ * task in a cgroup is in_memstall, the corresponding groupc
+ * on that cpu is in PSI_MEM_FULL state.
+ */
+ if (groupc->tasks[NR_ONCPU] && cpu_curr(cpu)->in_memstall)
+ state_mask |= (1 << PSI_MEM_FULL);
+
groupc->state_mask = state_mask;
write_seqcount_end(&groupc->seq);
void *iter;
if (next->pid) {
+ bool identical_state;
+
psi_flags_change(next, 0, TSK_ONCPU);
/*
- * When moving state between tasks, the group that
- * contains them both does not change: we can stop
- * updating the tree once we reach the first common
- * ancestor. Iterate @next's ancestors until we
- * encounter @prev's state.
+ * When switching between tasks that have an identical
+ * runtime state, the cgroup that contains both tasks
+ * runtime state, the cgroup that contains both tasks
+ * we reach the first common ancestor. Iterate @next's
+ * ancestors only until we encounter @prev's ONCPU.
*/
+ identical_state = prev->psi_flags == next->psi_flags;
iter = NULL;
while ((group = iterate_groups(next, &iter))) {
- if (per_cpu_ptr(group->pcpu, cpu)->tasks[NR_ONCPU]) {
+ if (identical_state &&
+ per_cpu_ptr(group->pcpu, cpu)->tasks[NR_ONCPU]) {
common = group;
break;
}
}
}
-void psi_memstall_tick(struct task_struct *task, int cpu)
-{
- struct psi_group *group;
- void *iter = NULL;
-
- while ((group = iterate_groups(task, &iter))) {
- struct psi_group_cpu *groupc;
-
- groupc = per_cpu_ptr(group->pcpu, cpu);
- write_seqcount_begin(&groupc->seq);
- record_times(groupc, cpu, true);
- write_seqcount_end(&groupc->seq);
- }
-}
-
/**
* psi_memstall_enter - mark the beginning of a memory stall section
* @flags: flags to handle nested sections