profile: don't include <asm/ptrace.h> twice.
[linux-2.6.git] / kernel / profile.c
1 /*
2  *  linux/kernel/profile.c
3  *  Simple profiling. Manages a direct-mapped profile hit count buffer,
4  *  with configurable resolution, support for restricting the cpus on
5  *  which profiling is done, and switching between cpu time and
6  *  schedule() calls via kernel command line parameters passed at boot.
7  *
8  *  Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
9  *      Red Hat, July 2004
10  *  Consolidation of architecture support code for profiling,
11  *      William Irwin, Oracle, July 2004
12  *  Amortized hit count accounting via per-cpu open-addressed hashtables
13  *      to resolve timer interrupt livelocks, William Irwin, Oracle, 2004
14  */
15
16 #include <linux/module.h>
17 #include <linux/profile.h>
18 #include <linux/bootmem.h>
19 #include <linux/notifier.h>
20 #include <linux/mm.h>
21 #include <linux/cpumask.h>
22 #include <linux/cpu.h>
23 #include <linux/highmem.h>
24 #include <linux/mutex.h>
25 #include <linux/slab.h>
26 #include <linux/vmalloc.h>
27 #include <asm/sections.h>
28 #include <asm/irq_regs.h>
29 #include <asm/ptrace.h>
30
31 struct profile_hit {
32         u32 pc, hits;
33 };
34 #define PROFILE_GRPSHIFT        3
35 #define PROFILE_GRPSZ           (1 << PROFILE_GRPSHIFT)
36 #define NR_PROFILE_HIT          (PAGE_SIZE/sizeof(struct profile_hit))
37 #define NR_PROFILE_GRP          (NR_PROFILE_HIT/PROFILE_GRPSZ)
38
39 /* Oprofile timer tick hook */
40 static int (*timer_hook)(struct pt_regs *) __read_mostly;
41
42 static atomic_t *prof_buffer;
43 static unsigned long prof_len, prof_shift;
44
45 int prof_on __read_mostly;
46 EXPORT_SYMBOL_GPL(prof_on);
47
48 static cpumask_var_t prof_cpu_mask;
49 #ifdef CONFIG_SMP
50 static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
51 static DEFINE_PER_CPU(int, cpu_profile_flip);
52 static DEFINE_MUTEX(profile_flip_mutex);
53 #endif /* CONFIG_SMP */
54
55 int profile_setup(char *str)
56 {
57         static char schedstr[] = "schedule";
58         static char sleepstr[] = "sleep";
59         static char kvmstr[] = "kvm";
60         int par;
61
62         if (!strncmp(str, sleepstr, strlen(sleepstr))) {
63 #ifdef CONFIG_SCHEDSTATS
64                 prof_on = SLEEP_PROFILING;
65                 if (str[strlen(sleepstr)] == ',')
66                         str += strlen(sleepstr) + 1;
67                 if (get_option(&str, &par))
68                         prof_shift = par;
69                 printk(KERN_INFO
70                         "kernel sleep profiling enabled (shift: %ld)\n",
71                         prof_shift);
72 #else
73                 printk(KERN_WARNING
74                         "kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
75 #endif /* CONFIG_SCHEDSTATS */
76         } else if (!strncmp(str, schedstr, strlen(schedstr))) {
77                 prof_on = SCHED_PROFILING;
78                 if (str[strlen(schedstr)] == ',')
79                         str += strlen(schedstr) + 1;
80                 if (get_option(&str, &par))
81                         prof_shift = par;
82                 printk(KERN_INFO
83                         "kernel schedule profiling enabled (shift: %ld)\n",
84                         prof_shift);
85         } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
86                 prof_on = KVM_PROFILING;
87                 if (str[strlen(kvmstr)] == ',')
88                         str += strlen(kvmstr) + 1;
89                 if (get_option(&str, &par))
90                         prof_shift = par;
91                 printk(KERN_INFO
92                         "kernel KVM profiling enabled (shift: %ld)\n",
93                         prof_shift);
94         } else if (get_option(&str, &par)) {
95                 prof_shift = par;
96                 prof_on = CPU_PROFILING;
97                 printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
98                         prof_shift);
99         }
100         return 1;
101 }
102 __setup("profile=", profile_setup);
103
104
105 int __ref profile_init(void)
106 {
107         int buffer_bytes;
108         if (!prof_on)
109                 return 0;
110
111         /* only text is profiled */
112         prof_len = (_etext - _stext) >> prof_shift;
113         buffer_bytes = prof_len*sizeof(atomic_t);
114         if (!slab_is_available()) {
115                 prof_buffer = alloc_bootmem(buffer_bytes);
116                 alloc_bootmem_cpumask_var(&prof_cpu_mask);
117                 return 0;
118         }
119
120         if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
121                 return -ENOMEM;
122
123         prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL);
124         if (prof_buffer)
125                 return 0;
126
127         prof_buffer = alloc_pages_exact(buffer_bytes, GFP_KERNEL|__GFP_ZERO);
128         if (prof_buffer)
129                 return 0;
130
131         prof_buffer = vmalloc(buffer_bytes);
132         if (prof_buffer)
133                 return 0;
134
135         free_cpumask_var(prof_cpu_mask);
136         return -ENOMEM;
137 }
138
139 /* Profile event notifications */
140
141 static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
142 static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
143 static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
144
145 void profile_task_exit(struct task_struct *task)
146 {
147         blocking_notifier_call_chain(&task_exit_notifier, 0, task);
148 }
149
150 int profile_handoff_task(struct task_struct *task)
151 {
152         int ret;
153         ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
154         return (ret == NOTIFY_OK) ? 1 : 0;
155 }
156
157 void profile_munmap(unsigned long addr)
158 {
159         blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
160 }
161
162 int task_handoff_register(struct notifier_block *n)
163 {
164         return atomic_notifier_chain_register(&task_free_notifier, n);
165 }
166 EXPORT_SYMBOL_GPL(task_handoff_register);
167
168 int task_handoff_unregister(struct notifier_block *n)
169 {
170         return atomic_notifier_chain_unregister(&task_free_notifier, n);
171 }
172 EXPORT_SYMBOL_GPL(task_handoff_unregister);
173
174 int profile_event_register(enum profile_type type, struct notifier_block *n)
175 {
176         int err = -EINVAL;
177
178         switch (type) {
179         case PROFILE_TASK_EXIT:
180                 err = blocking_notifier_chain_register(
181                                 &task_exit_notifier, n);
182                 break;
183         case PROFILE_MUNMAP:
184                 err = blocking_notifier_chain_register(
185                                 &munmap_notifier, n);
186                 break;
187         }
188
189         return err;
190 }
191 EXPORT_SYMBOL_GPL(profile_event_register);
192
193 int profile_event_unregister(enum profile_type type, struct notifier_block *n)
194 {
195         int err = -EINVAL;
196
197         switch (type) {
198         case PROFILE_TASK_EXIT:
199                 err = blocking_notifier_chain_unregister(
200                                 &task_exit_notifier, n);
201                 break;
202         case PROFILE_MUNMAP:
203                 err = blocking_notifier_chain_unregister(
204                                 &munmap_notifier, n);
205                 break;
206         }
207
208         return err;
209 }
210 EXPORT_SYMBOL_GPL(profile_event_unregister);
211
212 int register_timer_hook(int (*hook)(struct pt_regs *))
213 {
214         if (timer_hook)
215                 return -EBUSY;
216         timer_hook = hook;
217         return 0;
218 }
219 EXPORT_SYMBOL_GPL(register_timer_hook);
220
221 void unregister_timer_hook(int (*hook)(struct pt_regs *))
222 {
223         WARN_ON(hook != timer_hook);
224         timer_hook = NULL;
225         /* make sure all CPUs see the NULL hook */
226         synchronize_sched();  /* Allow ongoing interrupts to complete. */
227 }
228 EXPORT_SYMBOL_GPL(unregister_timer_hook);
229
230
231 #ifdef CONFIG_SMP
232 /*
233  * Each cpu has a pair of open-addressed hashtables for pending
234  * profile hits. read_profile() IPI's all cpus to request them
235  * to flip buffers and flushes their contents to prof_buffer itself.
236  * Flip requests are serialized by the profile_flip_mutex. The sole
237  * use of having a second hashtable is for avoiding cacheline
238  * contention that would otherwise happen during flushes of pending
239  * profile hits required for the accuracy of reported profile hits
240  * and so resurrect the interrupt livelock issue.
241  *
242  * The open-addressed hashtables are indexed by profile buffer slot
243  * and hold the number of pending hits to that profile buffer slot on
244  * a cpu in an entry. When the hashtable overflows, all pending hits
245  * are accounted to their corresponding profile buffer slots with
246  * atomic_add() and the hashtable emptied. As numerous pending hits
247  * may be accounted to a profile buffer slot in a hashtable entry,
248  * this amortizes a number of atomic profile buffer increments likely
249  * to be far larger than the number of entries in the hashtable,
250  * particularly given that the number of distinct profile buffer
251  * positions to which hits are accounted during short intervals (e.g.
252  * several seconds) is usually very small. Exclusion from buffer
253  * flipping is provided by interrupt disablement (note that for
254  * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
255  * process context).
256  * The hash function is meant to be lightweight as opposed to strong,
257  * and was vaguely inspired by ppc64 firmware-supported inverted
258  * pagetable hash functions, but uses a full hashtable full of finite
259  * collision chains, not just pairs of them.
260  *
261  * -- wli
262  */
263 static void __profile_flip_buffers(void *unused)
264 {
265         int cpu = smp_processor_id();
266
267         per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
268 }
269
270 static void profile_flip_buffers(void)
271 {
272         int i, j, cpu;
273
274         mutex_lock(&profile_flip_mutex);
275         j = per_cpu(cpu_profile_flip, get_cpu());
276         put_cpu();
277         on_each_cpu(__profile_flip_buffers, NULL, 1);
278         for_each_online_cpu(cpu) {
279                 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
280                 for (i = 0; i < NR_PROFILE_HIT; ++i) {
281                         if (!hits[i].hits) {
282                                 if (hits[i].pc)
283                                         hits[i].pc = 0;
284                                 continue;
285                         }
286                         atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
287                         hits[i].hits = hits[i].pc = 0;
288                 }
289         }
290         mutex_unlock(&profile_flip_mutex);
291 }
292
293 static void profile_discard_flip_buffers(void)
294 {
295         int i, cpu;
296
297         mutex_lock(&profile_flip_mutex);
298         i = per_cpu(cpu_profile_flip, get_cpu());
299         put_cpu();
300         on_each_cpu(__profile_flip_buffers, NULL, 1);
301         for_each_online_cpu(cpu) {
302                 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
303                 memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
304         }
305         mutex_unlock(&profile_flip_mutex);
306 }
307
308 void profile_hits(int type, void *__pc, unsigned int nr_hits)
309 {
310         unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
311         int i, j, cpu;
312         struct profile_hit *hits;
313
314         if (prof_on != type || !prof_buffer)
315                 return;
316         pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
317         i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
318         secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
319         cpu = get_cpu();
320         hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
321         if (!hits) {
322                 put_cpu();
323                 return;
324         }
325         /*
326          * We buffer the global profiler buffer into a per-CPU
327          * queue and thus reduce the number of global (and possibly
328          * NUMA-alien) accesses. The write-queue is self-coalescing:
329          */
330         local_irq_save(flags);
331         do {
332                 for (j = 0; j < PROFILE_GRPSZ; ++j) {
333                         if (hits[i + j].pc == pc) {
334                                 hits[i + j].hits += nr_hits;
335                                 goto out;
336                         } else if (!hits[i + j].hits) {
337                                 hits[i + j].pc = pc;
338                                 hits[i + j].hits = nr_hits;
339                                 goto out;
340                         }
341                 }
342                 i = (i + secondary) & (NR_PROFILE_HIT - 1);
343         } while (i != primary);
344
345         /*
346          * Add the current hit(s) and flush the write-queue out
347          * to the global buffer:
348          */
349         atomic_add(nr_hits, &prof_buffer[pc]);
350         for (i = 0; i < NR_PROFILE_HIT; ++i) {
351                 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
352                 hits[i].pc = hits[i].hits = 0;
353         }
354 out:
355         local_irq_restore(flags);
356         put_cpu();
357 }
358
359 static int __cpuinit profile_cpu_callback(struct notifier_block *info,
360                                         unsigned long action, void *__cpu)
361 {
362         int node, cpu = (unsigned long)__cpu;
363         struct page *page;
364
365         switch (action) {
366         case CPU_UP_PREPARE:
367         case CPU_UP_PREPARE_FROZEN:
368                 node = cpu_to_node(cpu);
369                 per_cpu(cpu_profile_flip, cpu) = 0;
370                 if (!per_cpu(cpu_profile_hits, cpu)[1]) {
371                         page = alloc_pages_node(node,
372                                         GFP_KERNEL | __GFP_ZERO,
373                                         0);
374                         if (!page)
375                                 return NOTIFY_BAD;
376                         per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
377                 }
378                 if (!per_cpu(cpu_profile_hits, cpu)[0]) {
379                         page = alloc_pages_node(node,
380                                         GFP_KERNEL | __GFP_ZERO,
381                                         0);
382                         if (!page)
383                                 goto out_free;
384                         per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
385                 }
386                 break;
387 out_free:
388                 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
389                 per_cpu(cpu_profile_hits, cpu)[1] = NULL;
390                 __free_page(page);
391                 return NOTIFY_BAD;
392         case CPU_ONLINE:
393         case CPU_ONLINE_FROZEN:
394                 if (prof_cpu_mask != NULL)
395                         cpumask_set_cpu(cpu, prof_cpu_mask);
396                 break;
397         case CPU_UP_CANCELED:
398         case CPU_UP_CANCELED_FROZEN:
399         case CPU_DEAD:
400         case CPU_DEAD_FROZEN:
401                 if (prof_cpu_mask != NULL)
402                         cpumask_clear_cpu(cpu, prof_cpu_mask);
403                 if (per_cpu(cpu_profile_hits, cpu)[0]) {
404                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
405                         per_cpu(cpu_profile_hits, cpu)[0] = NULL;
406                         __free_page(page);
407                 }
408                 if (per_cpu(cpu_profile_hits, cpu)[1]) {
409                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
410                         per_cpu(cpu_profile_hits, cpu)[1] = NULL;
411                         __free_page(page);
412                 }
413                 break;
414         }
415         return NOTIFY_OK;
416 }
417 #else /* !CONFIG_SMP */
418 #define profile_flip_buffers()          do { } while (0)
419 #define profile_discard_flip_buffers()  do { } while (0)
420 #define profile_cpu_callback            NULL
421
422 void profile_hits(int type, void *__pc, unsigned int nr_hits)
423 {
424         unsigned long pc;
425
426         if (prof_on != type || !prof_buffer)
427                 return;
428         pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
429         atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
430 }
431 #endif /* !CONFIG_SMP */
432 EXPORT_SYMBOL_GPL(profile_hits);
433
434 void profile_tick(int type)
435 {
436         struct pt_regs *regs = get_irq_regs();
437
438         if (type == CPU_PROFILING && timer_hook)
439                 timer_hook(regs);
440         if (!user_mode(regs) && prof_cpu_mask != NULL &&
441             cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
442                 profile_hit(type, (void *)profile_pc(regs));
443 }
444
445 #ifdef CONFIG_PROC_FS
446 #include <linux/proc_fs.h>
447 #include <asm/uaccess.h>
448
449 static int prof_cpu_mask_read_proc(char *page, char **start, off_t off,
450                         int count, int *eof, void *data)
451 {
452         int len = cpumask_scnprintf(page, count, data);
453         if (count - len < 2)
454                 return -EINVAL;
455         len += sprintf(page + len, "\n");
456         return len;
457 }
458
459 static int prof_cpu_mask_write_proc(struct file *file,
460         const char __user *buffer,  unsigned long count, void *data)
461 {
462         struct cpumask *mask = data;
463         unsigned long full_count = count, err;
464         cpumask_var_t new_value;
465
466         if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
467                 return -ENOMEM;
468
469         err = cpumask_parse_user(buffer, count, new_value);
470         if (!err) {
471                 cpumask_copy(mask, new_value);
472                 err = full_count;
473         }
474         free_cpumask_var(new_value);
475         return err;
476 }
477
478 void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
479 {
480         struct proc_dir_entry *entry;
481
482         /* create /proc/irq/prof_cpu_mask */
483         entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
484         if (!entry)
485                 return;
486         entry->data = prof_cpu_mask;
487         entry->read_proc = prof_cpu_mask_read_proc;
488         entry->write_proc = prof_cpu_mask_write_proc;
489 }
490
491 /*
492  * This function accesses profiling information. The returned data is
493  * binary: the sampling step and the actual contents of the profile
494  * buffer. Use of the program readprofile is recommended in order to
495  * get meaningful info out of these data.
496  */
497 static ssize_t
498 read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
499 {
500         unsigned long p = *ppos;
501         ssize_t read;
502         char *pnt;
503         unsigned int sample_step = 1 << prof_shift;
504
505         profile_flip_buffers();
506         if (p >= (prof_len+1)*sizeof(unsigned int))
507                 return 0;
508         if (count > (prof_len+1)*sizeof(unsigned int) - p)
509                 count = (prof_len+1)*sizeof(unsigned int) - p;
510         read = 0;
511
512         while (p < sizeof(unsigned int) && count > 0) {
513                 if (put_user(*((char *)(&sample_step)+p), buf))
514                         return -EFAULT;
515                 buf++; p++; count--; read++;
516         }
517         pnt = (char *)prof_buffer + p - sizeof(atomic_t);
518         if (copy_to_user(buf, (void *)pnt, count))
519                 return -EFAULT;
520         read += count;
521         *ppos += read;
522         return read;
523 }
524
525 /*
526  * Writing to /proc/profile resets the counters
527  *
528  * Writing a 'profiling multiplier' value into it also re-sets the profiling
529  * interrupt frequency, on architectures that support this.
530  */
531 static ssize_t write_profile(struct file *file, const char __user *buf,
532                              size_t count, loff_t *ppos)
533 {
534 #ifdef CONFIG_SMP
535         extern int setup_profiling_timer(unsigned int multiplier);
536
537         if (count == sizeof(int)) {
538                 unsigned int multiplier;
539
540                 if (copy_from_user(&multiplier, buf, sizeof(int)))
541                         return -EFAULT;
542
543                 if (setup_profiling_timer(multiplier))
544                         return -EINVAL;
545         }
546 #endif
547         profile_discard_flip_buffers();
548         memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
549         return count;
550 }
551
552 static const struct file_operations proc_profile_operations = {
553         .read           = read_profile,
554         .write          = write_profile,
555 };
556
557 #ifdef CONFIG_SMP
558 static void profile_nop(void *unused)
559 {
560 }
561
562 static int create_hash_tables(void)
563 {
564         int cpu;
565
566         for_each_online_cpu(cpu) {
567                 int node = cpu_to_node(cpu);
568                 struct page *page;
569
570                 page = alloc_pages_node(node,
571                                 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
572                                 0);
573                 if (!page)
574                         goto out_cleanup;
575                 per_cpu(cpu_profile_hits, cpu)[1]
576                                 = (struct profile_hit *)page_address(page);
577                 page = alloc_pages_node(node,
578                                 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
579                                 0);
580                 if (!page)
581                         goto out_cleanup;
582                 per_cpu(cpu_profile_hits, cpu)[0]
583                                 = (struct profile_hit *)page_address(page);
584         }
585         return 0;
586 out_cleanup:
587         prof_on = 0;
588         smp_mb();
589         on_each_cpu(profile_nop, NULL, 1);
590         for_each_online_cpu(cpu) {
591                 struct page *page;
592
593                 if (per_cpu(cpu_profile_hits, cpu)[0]) {
594                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
595                         per_cpu(cpu_profile_hits, cpu)[0] = NULL;
596                         __free_page(page);
597                 }
598                 if (per_cpu(cpu_profile_hits, cpu)[1]) {
599                         page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
600                         per_cpu(cpu_profile_hits, cpu)[1] = NULL;
601                         __free_page(page);
602                 }
603         }
604         return -1;
605 }
606 #else
607 #define create_hash_tables()                    ({ 0; })
608 #endif
609
610 int __ref create_proc_profile(void) /* false positive from hotcpu_notifier */
611 {
612         struct proc_dir_entry *entry;
613
614         if (!prof_on)
615                 return 0;
616         if (create_hash_tables())
617                 return -ENOMEM;
618         entry = proc_create("profile", S_IWUSR | S_IRUGO,
619                             NULL, &proc_profile_operations);
620         if (!entry)
621                 return 0;
622         entry->size = (1+prof_len) * sizeof(atomic_t);
623         hotcpu_notifier(profile_cpu_callback, 0);
624         return 0;
625 }
626 module_init(create_proc_profile);
627 #endif /* CONFIG_PROC_FS */