aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/trace/trace_workqueue.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/trace/trace_workqueue.c')
-rw-r--r--kernel/trace/trace_workqueue.c288
1 files changed, 288 insertions, 0 deletions
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
new file mode 100644
index 000000000000..797201e4a137
--- /dev/null
+++ b/kernel/trace/trace_workqueue.c
@@ -0,0 +1,288 @@
1/*
2 * Workqueue statistical tracer.
3 *
4 * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
5 *
6 */
7
8
9#include <trace/workqueue.h>
10#include <linux/list.h>
11#include <linux/percpu.h>
12#include "trace_stat.h"
13#include "trace.h"
14
15
16/* A cpu workqueue thread */
17struct cpu_workqueue_stats {
18 struct list_head list;
19/* Useful to know if we print the cpu headers */
20 bool first_entry;
21 int cpu;
22 pid_t pid;
23/* Can be inserted from interrupt or user context, need to be atomic */
24 atomic_t inserted;
25/*
26 * Don't need to be atomic, works are serialized in a single workqueue thread
27 * on a single CPU.
28 */
29 unsigned int executed;
30};
31
32/* List of workqueue threads on one cpu */
33struct workqueue_global_stats {
34 struct list_head list;
35 spinlock_t lock;
36};
37
38/* Don't need a global lock because allocated before the workqueues, and
39 * never freed.
40 */
41static DEFINE_PER_CPU(struct workqueue_global_stats, all_workqueue_stat);
42#define workqueue_cpu_stat(cpu) (&per_cpu(all_workqueue_stat, cpu))
43
44/* Insertion of a work */
45static void
46probe_workqueue_insertion(struct task_struct *wq_thread,
47 struct work_struct *work)
48{
49 int cpu = cpumask_first(&wq_thread->cpus_allowed);
50 struct cpu_workqueue_stats *node, *next;
51 unsigned long flags;
52
53 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
54 list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
55 list) {
56 if (node->pid == wq_thread->pid) {
57 atomic_inc(&node->inserted);
58 goto found;
59 }
60 }
61 pr_debug("trace_workqueue: entry not found\n");
62found:
63 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
64}
65
66/* Execution of a work */
67static void
68probe_workqueue_execution(struct task_struct *wq_thread,
69 struct work_struct *work)
70{
71 int cpu = cpumask_first(&wq_thread->cpus_allowed);
72 struct cpu_workqueue_stats *node, *next;
73 unsigned long flags;
74
75 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
76 list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
77 list) {
78 if (node->pid == wq_thread->pid) {
79 node->executed++;
80 goto found;
81 }
82 }
83 pr_debug("trace_workqueue: entry not found\n");
84found:
85 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
86}
87
88/* Creation of a cpu workqueue thread */
89static void probe_workqueue_creation(struct task_struct *wq_thread, int cpu)
90{
91 struct cpu_workqueue_stats *cws;
92 unsigned long flags;
93
94 WARN_ON(cpu < 0);
95
96 /* Workqueues are sometimes created in atomic context */
97 cws = kzalloc(sizeof(struct cpu_workqueue_stats), GFP_ATOMIC);
98 if (!cws) {
99 pr_warning("trace_workqueue: not enough memory\n");
100 return;
101 }
102 INIT_LIST_HEAD(&cws->list);
103 cws->cpu = cpu;
104
105 cws->pid = wq_thread->pid;
106
107 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
108 if (list_empty(&workqueue_cpu_stat(cpu)->list))
109 cws->first_entry = true;
110 list_add_tail(&cws->list, &workqueue_cpu_stat(cpu)->list);
111 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
112}
113
114/* Destruction of a cpu workqueue thread */
115static void probe_workqueue_destruction(struct task_struct *wq_thread)
116{
117 /* Workqueue only execute on one cpu */
118 int cpu = cpumask_first(&wq_thread->cpus_allowed);
119 struct cpu_workqueue_stats *node, *next;
120 unsigned long flags;
121
122 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
123 list_for_each_entry_safe(node, next, &workqueue_cpu_stat(cpu)->list,
124 list) {
125 if (node->pid == wq_thread->pid) {
126 list_del(&node->list);
127 kfree(node);
128 goto found;
129 }
130 }
131
132 pr_debug("trace_workqueue: don't find workqueue to destroy\n");
133found:
134 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
135
136}
137
138static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu)
139{
140 unsigned long flags;
141 struct cpu_workqueue_stats *ret = NULL;
142
143
144 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
145
146 if (!list_empty(&workqueue_cpu_stat(cpu)->list))
147 ret = list_entry(workqueue_cpu_stat(cpu)->list.next,
148 struct cpu_workqueue_stats, list);
149
150 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
151
152 return ret;
153}
154
155static void *workqueue_stat_start(void)
156{
157 int cpu;
158 void *ret = NULL;
159
160 for_each_possible_cpu(cpu) {
161 ret = workqueue_stat_start_cpu(cpu);
162 if (ret)
163 return ret;
164 }
165 return NULL;
166}
167
168static void *workqueue_stat_next(void *prev, int idx)
169{
170 struct cpu_workqueue_stats *prev_cws = prev;
171 int cpu = prev_cws->cpu;
172 unsigned long flags;
173 void *ret = NULL;
174
175 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
176 if (list_is_last(&prev_cws->list, &workqueue_cpu_stat(cpu)->list)) {
177 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
178 do {
179 cpu = cpumask_next(cpu, cpu_possible_mask);
180 if (cpu >= nr_cpu_ids)
181 return NULL;
182 } while (!(ret = workqueue_stat_start_cpu(cpu)));
183 return ret;
184 }
185 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
186
187 return list_entry(prev_cws->list.next, struct cpu_workqueue_stats,
188 list);
189}
190
191static int workqueue_stat_show(struct seq_file *s, void *p)
192{
193 struct cpu_workqueue_stats *cws = p;
194 unsigned long flags;
195 int cpu = cws->cpu;
196 struct pid *pid;
197 struct task_struct *tsk;
198
199 spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
200 if (&cws->list == workqueue_cpu_stat(cpu)->list.next)
201 seq_printf(s, "\n");
202 spin_unlock_irqrestore(&workqueue_cpu_stat(cpu)->lock, flags);
203
204 pid = find_get_pid(cws->pid);
205 if (pid) {
206 tsk = get_pid_task(pid, PIDTYPE_PID);
207 if (tsk) {
208 seq_printf(s, "%3d %6d %6u %s\n", cws->cpu,
209 atomic_read(&cws->inserted), cws->executed,
210 tsk->comm);
211 put_task_struct(tsk);
212 }
213 put_pid(pid);
214 }
215
216 return 0;
217}
218
219static int workqueue_stat_headers(struct seq_file *s)
220{
221 seq_printf(s, "# CPU INSERTED EXECUTED NAME\n");
222 seq_printf(s, "# | | | |\n");
223 return 0;
224}
225
226struct tracer_stat workqueue_stats __read_mostly = {
227 .name = "workqueues",
228 .stat_start = workqueue_stat_start,
229 .stat_next = workqueue_stat_next,
230 .stat_show = workqueue_stat_show,
231 .stat_headers = workqueue_stat_headers
232};
233
234
235int __init stat_workqueue_init(void)
236{
237 if (register_stat_tracer(&workqueue_stats)) {
238 pr_warning("Unable to register workqueue stat tracer\n");
239 return 1;
240 }
241
242 return 0;
243}
244fs_initcall(stat_workqueue_init);
245
246/*
247 * Workqueues are created very early, just after pre-smp initcalls.
248 * So we must register our tracepoints at this stage.
249 */
250int __init trace_workqueue_early_init(void)
251{
252 int ret, cpu;
253
254 ret = register_trace_workqueue_insertion(probe_workqueue_insertion);
255 if (ret)
256 goto out;
257
258 ret = register_trace_workqueue_execution(probe_workqueue_execution);
259 if (ret)
260 goto no_insertion;
261
262 ret = register_trace_workqueue_creation(probe_workqueue_creation);
263 if (ret)
264 goto no_execution;
265
266 ret = register_trace_workqueue_destruction(probe_workqueue_destruction);
267 if (ret)
268 goto no_creation;
269
270 for_each_possible_cpu(cpu) {
271 spin_lock_init(&workqueue_cpu_stat(cpu)->lock);
272 INIT_LIST_HEAD(&workqueue_cpu_stat(cpu)->list);
273 }
274
275 return 0;
276
277no_creation:
278 unregister_trace_workqueue_creation(probe_workqueue_creation);
279no_execution:
280 unregister_trace_workqueue_execution(probe_workqueue_execution);
281no_insertion:
282 unregister_trace_workqueue_insertion(probe_workqueue_insertion);
283out:
284 pr_warning("trace_workqueue: unable to trace workqueues\n");
285
286 return 1;
287}
288early_initcall(trace_workqueue_early_init);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-17 20:38:37 -0500