diff options
Diffstat (limited to 'kernel/trace/trace_workqueue.c')
-rw-r--r-- | kernel/trace/trace_workqueue.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c new file mode 100644 index 000000000000..f8118d39ca9b --- /dev/null +++ b/kernel/trace/trace_workqueue.c | |||
@@ -0,0 +1,287 @@ | |||
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 "trace_stat.h" | ||
12 | #include "trace.h" | ||
13 | |||
14 | |||
15 | /* A cpu workqueue thread */ | ||
16 | struct cpu_workqueue_stats { | ||
17 | struct list_head list; | ||
18 | /* Useful to know if we print the cpu headers */ | ||
19 | bool first_entry; | ||
20 | int cpu; | ||
21 | pid_t pid; | ||
22 | /* Can be inserted from interrupt or user context, need to be atomic */ | ||
23 | atomic_t inserted; | ||
24 | /* | ||
25 | * Don't need to be atomic, works are serialized in a single workqueue thread | ||
26 | * on a single CPU. | ||
27 | */ | ||
28 | unsigned int executed; | ||
29 | }; | ||
30 | |||
31 | /* List of workqueue threads on one cpu */ | ||
32 | struct workqueue_global_stats { | ||
33 | struct list_head list; | ||
34 | spinlock_t lock; | ||
35 | }; | ||
36 | |||
37 | /* Don't need a global lock because allocated before the workqueues, and | ||
38 | * never freed. | ||
39 | */ | ||
40 | static struct workqueue_global_stats *all_workqueue_stat; | ||
41 | |||
42 | /* Insertion of a work */ | ||
43 | static void | ||
44 | probe_workqueue_insertion(struct task_struct *wq_thread, | ||
45 | struct work_struct *work) | ||
46 | { | ||
47 | int cpu = cpumask_first(&wq_thread->cpus_allowed); | ||
48 | struct cpu_workqueue_stats *node, *next; | ||
49 | unsigned long flags; | ||
50 | |||
51 | spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags); | ||
52 | list_for_each_entry_safe(node, next, &all_workqueue_stat[cpu].list, | ||
53 | list) { | ||
54 | if (node->pid == wq_thread->pid) { | ||
55 | atomic_inc(&node->inserted); | ||
56 | goto found; | ||
57 | } | ||
58 | } | ||
59 | pr_debug("trace_workqueue: entry not found\n"); | ||
60 | found: | ||
61 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
62 | } | ||
63 | |||
64 | /* Execution of a work */ | ||
65 | static void | ||
66 | probe_workqueue_execution(struct task_struct *wq_thread, | ||
67 | struct work_struct *work) | ||
68 | { | ||
69 | int cpu = cpumask_first(&wq_thread->cpus_allowed); | ||
70 | struct cpu_workqueue_stats *node, *next; | ||
71 | unsigned long flags; | ||
72 | |||
73 | spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags); | ||
74 | list_for_each_entry_safe(node, next, &all_workqueue_stat[cpu].list, | ||
75 | list) { | ||
76 | if (node->pid == wq_thread->pid) { | ||
77 | node->executed++; | ||
78 | goto found; | ||
79 | } | ||
80 | } | ||
81 | pr_debug("trace_workqueue: entry not found\n"); | ||
82 | found: | ||
83 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
84 | } | ||
85 | |||
86 | /* Creation of a cpu workqueue thread */ | ||
87 | static void probe_workqueue_creation(struct task_struct *wq_thread, int cpu) | ||
88 | { | ||
89 | struct cpu_workqueue_stats *cws; | ||
90 | unsigned long flags; | ||
91 | |||
92 | WARN_ON(cpu < 0 || cpu >= num_possible_cpus()); | ||
93 | |||
94 | /* Workqueues are sometimes created in atomic context */ | ||
95 | cws = kzalloc(sizeof(struct cpu_workqueue_stats), GFP_ATOMIC); | ||
96 | if (!cws) { | ||
97 | pr_warning("trace_workqueue: not enough memory\n"); | ||
98 | return; | ||
99 | } | ||
100 | tracing_record_cmdline(wq_thread); | ||
101 | |||
102 | INIT_LIST_HEAD(&cws->list); | ||
103 | cws->cpu = cpu; | ||
104 | |||
105 | cws->pid = wq_thread->pid; | ||
106 | |||
107 | spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags); | ||
108 | if (list_empty(&all_workqueue_stat[cpu].list)) | ||
109 | cws->first_entry = true; | ||
110 | list_add_tail(&cws->list, &all_workqueue_stat[cpu].list); | ||
111 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
112 | } | ||
113 | |||
114 | /* Destruction of a cpu workqueue thread */ | ||
115 | static 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(&all_workqueue_stat[cpu].lock, flags); | ||
123 | list_for_each_entry_safe(node, next, &all_workqueue_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"); | ||
133 | found: | ||
134 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
135 | |||
136 | } | ||
137 | |||
138 | static 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(&all_workqueue_stat[cpu].lock, flags); | ||
145 | |||
146 | if (!list_empty(&all_workqueue_stat[cpu].list)) | ||
147 | ret = list_entry(all_workqueue_stat[cpu].list.next, | ||
148 | struct cpu_workqueue_stats, list); | ||
149 | |||
150 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
151 | |||
152 | return ret; | ||
153 | } | ||
154 | |||
155 | static 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 | |||
168 | static 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(&all_workqueue_stat[cpu].lock, flags); | ||
176 | if (list_is_last(&prev_cws->list, &all_workqueue_stat[cpu].list)) { | ||
177 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
178 | for (++cpu ; cpu < num_possible_cpus(); cpu++) { | ||
179 | ret = workqueue_stat_start_cpu(cpu); | ||
180 | if (ret) | ||
181 | return ret; | ||
182 | } | ||
183 | return NULL; | ||
184 | } | ||
185 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
186 | |||
187 | return list_entry(prev_cws->list.next, struct cpu_workqueue_stats, | ||
188 | list); | ||
189 | } | ||
190 | |||
191 | static 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 | |||
197 | seq_printf(s, "%3d %6d %6u %s\n", cws->cpu, | ||
198 | atomic_read(&cws->inserted), | ||
199 | cws->executed, | ||
200 | trace_find_cmdline(cws->pid)); | ||
201 | |||
202 | spin_lock_irqsave(&all_workqueue_stat[cpu].lock, flags); | ||
203 | if (&cws->list == all_workqueue_stat[cpu].list.next) | ||
204 | seq_printf(s, "\n"); | ||
205 | spin_unlock_irqrestore(&all_workqueue_stat[cpu].lock, flags); | ||
206 | |||
207 | return 0; | ||
208 | } | ||
209 | |||
210 | static int workqueue_stat_headers(struct seq_file *s) | ||
211 | { | ||
212 | seq_printf(s, "# CPU INSERTED EXECUTED NAME\n"); | ||
213 | seq_printf(s, "# | | | |\n\n"); | ||
214 | return 0; | ||
215 | } | ||
216 | |||
217 | struct tracer_stat workqueue_stats __read_mostly = { | ||
218 | .name = "workqueues", | ||
219 | .stat_start = workqueue_stat_start, | ||
220 | .stat_next = workqueue_stat_next, | ||
221 | .stat_show = workqueue_stat_show, | ||
222 | .stat_headers = workqueue_stat_headers | ||
223 | }; | ||
224 | |||
225 | |||
226 | int __init stat_workqueue_init(void) | ||
227 | { | ||
228 | if (register_stat_tracer(&workqueue_stats)) { | ||
229 | pr_warning("Unable to register workqueue stat tracer\n"); | ||
230 | return 1; | ||
231 | } | ||
232 | |||
233 | return 0; | ||
234 | } | ||
235 | fs_initcall(stat_workqueue_init); | ||
236 | |||
237 | /* | ||
238 | * Workqueues are created very early, just after pre-smp initcalls. | ||
239 | * So we must register our tracepoints at this stage. | ||
240 | */ | ||
241 | int __init trace_workqueue_early_init(void) | ||
242 | { | ||
243 | int ret, cpu; | ||
244 | |||
245 | ret = register_trace_workqueue_insertion(probe_workqueue_insertion); | ||
246 | if (ret) | ||
247 | goto out; | ||
248 | |||
249 | ret = register_trace_workqueue_execution(probe_workqueue_execution); | ||
250 | if (ret) | ||
251 | goto no_insertion; | ||
252 | |||
253 | ret = register_trace_workqueue_creation(probe_workqueue_creation); | ||
254 | if (ret) | ||
255 | goto no_execution; | ||
256 | |||
257 | ret = register_trace_workqueue_destruction(probe_workqueue_destruction); | ||
258 | if (ret) | ||
259 | goto no_creation; | ||
260 | |||
261 | all_workqueue_stat = kmalloc(sizeof(struct workqueue_global_stats) | ||
262 | * num_possible_cpus(), GFP_KERNEL); | ||
263 | |||
264 | if (!all_workqueue_stat) { | ||
265 | pr_warning("trace_workqueue: not enough memory\n"); | ||
266 | goto no_creation; | ||
267 | } | ||
268 | |||
269 | for_each_possible_cpu(cpu) { | ||
270 | spin_lock_init(&all_workqueue_stat[cpu].lock); | ||
271 | INIT_LIST_HEAD(&all_workqueue_stat[cpu].list); | ||
272 | } | ||
273 | |||
274 | return 0; | ||
275 | |||
276 | no_creation: | ||
277 | unregister_trace_workqueue_creation(probe_workqueue_creation); | ||
278 | no_execution: | ||
279 | unregister_trace_workqueue_execution(probe_workqueue_execution); | ||
280 | no_insertion: | ||
281 | unregister_trace_workqueue_insertion(probe_workqueue_insertion); | ||
282 | out: | ||
283 | pr_warning("trace_workqueue: unable to trace workqueues\n"); | ||
284 | |||
285 | return 1; | ||
286 | } | ||
287 | early_initcall(trace_workqueue_early_init); | ||