Linux kernel mirror (for testing)
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1#ifndef _LINUX_PSI_TYPES_H
2#define _LINUX_PSI_TYPES_H
3
4#include <linux/kthread.h>
5#include <linux/seqlock.h>
6#include <linux/types.h>
7#include <linux/kref.h>
8#include <linux/wait.h>
9
10#ifdef CONFIG_PSI
11
12/* Tracked task states */
13enum psi_task_count {
14 NR_IOWAIT,
15 NR_MEMSTALL,
16 NR_RUNNING,
17 /*
18 * This can't have values other than 0 or 1 and could be
19 * implemented as a bit flag. But for now we still have room
20 * in the first cacheline of psi_group_cpu, and this way we
21 * don't have to special case any state tracking for it.
22 */
23 NR_ONCPU,
24 NR_PSI_TASK_COUNTS = 4,
25};
26
27/* Task state bitmasks */
28#define TSK_IOWAIT (1 << NR_IOWAIT)
29#define TSK_MEMSTALL (1 << NR_MEMSTALL)
30#define TSK_RUNNING (1 << NR_RUNNING)
31#define TSK_ONCPU (1 << NR_ONCPU)
32
33/* Resources that workloads could be stalled on */
34enum psi_res {
35 PSI_IO,
36 PSI_MEM,
37 PSI_CPU,
38 NR_PSI_RESOURCES = 3,
39};
40
41/*
42 * Pressure states for each resource:
43 *
44 * SOME: Stalled tasks & working tasks
45 * FULL: Stalled tasks & no working tasks
46 */
47enum psi_states {
48 PSI_IO_SOME,
49 PSI_IO_FULL,
50 PSI_MEM_SOME,
51 PSI_MEM_FULL,
52 PSI_CPU_SOME,
53 PSI_CPU_FULL,
54 /* Only per-CPU, to weigh the CPU in the global average: */
55 PSI_NONIDLE,
56 NR_PSI_STATES = 7,
57};
58
59enum psi_aggregators {
60 PSI_AVGS = 0,
61 PSI_POLL,
62 NR_PSI_AGGREGATORS,
63};
64
65struct psi_group_cpu {
66 /* 1st cacheline updated by the scheduler */
67
68 /* Aggregator needs to know of concurrent changes */
69 seqcount_t seq ____cacheline_aligned_in_smp;
70
71 /* States of the tasks belonging to this group */
72 unsigned int tasks[NR_PSI_TASK_COUNTS];
73
74 /* Aggregate pressure state derived from the tasks */
75 u32 state_mask;
76
77 /* Period time sampling buckets for each state of interest (ns) */
78 u32 times[NR_PSI_STATES];
79
80 /* Time of last task change in this group (rq_clock) */
81 u64 state_start;
82
83 /* 2nd cacheline updated by the aggregator */
84
85 /* Delta detection against the sampling buckets */
86 u32 times_prev[NR_PSI_AGGREGATORS][NR_PSI_STATES]
87 ____cacheline_aligned_in_smp;
88};
89
90/* PSI growth tracking window */
91struct psi_window {
92 /* Window size in ns */
93 u64 size;
94
95 /* Start time of the current window in ns */
96 u64 start_time;
97
98 /* Value at the start of the window */
99 u64 start_value;
100
101 /* Value growth in the previous window */
102 u64 prev_growth;
103};
104
105struct psi_trigger {
106 /* PSI state being monitored by the trigger */
107 enum psi_states state;
108
109 /* User-spacified threshold in ns */
110 u64 threshold;
111
112 /* List node inside triggers list */
113 struct list_head node;
114
115 /* Backpointer needed during trigger destruction */
116 struct psi_group *group;
117
118 /* Wait queue for polling */
119 wait_queue_head_t event_wait;
120
121 /* Pending event flag */
122 int event;
123
124 /* Tracking window */
125 struct psi_window win;
126
127 /*
128 * Time last event was generated. Used for rate-limiting
129 * events to one per window
130 */
131 u64 last_event_time;
132
133 /* Refcounting to prevent premature destruction */
134 struct kref refcount;
135};
136
137struct psi_group {
138 /* Protects data used by the aggregator */
139 struct mutex avgs_lock;
140
141 /* Per-cpu task state & time tracking */
142 struct psi_group_cpu __percpu *pcpu;
143
144 /* Running pressure averages */
145 u64 avg_total[NR_PSI_STATES - 1];
146 u64 avg_last_update;
147 u64 avg_next_update;
148
149 /* Aggregator work control */
150 struct delayed_work avgs_work;
151
152 /* Total stall times and sampled pressure averages */
153 u64 total[NR_PSI_AGGREGATORS][NR_PSI_STATES - 1];
154 unsigned long avg[NR_PSI_STATES - 1][3];
155
156 /* Monitor work control */
157 struct task_struct __rcu *poll_task;
158 struct timer_list poll_timer;
159 wait_queue_head_t poll_wait;
160 atomic_t poll_wakeup;
161
162 /* Protects data used by the monitor */
163 struct mutex trigger_lock;
164
165 /* Configured polling triggers */
166 struct list_head triggers;
167 u32 nr_triggers[NR_PSI_STATES - 1];
168 u32 poll_states;
169 u64 poll_min_period;
170
171 /* Total stall times at the start of monitor activation */
172 u64 polling_total[NR_PSI_STATES - 1];
173 u64 polling_next_update;
174 u64 polling_until;
175};
176
177#else /* CONFIG_PSI */
178
179struct psi_group { };
180
181#endif /* CONFIG_PSI */
182
183#endif /* _LINUX_PSI_TYPES_H */