| 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 | |
| 115 | if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL)) |
| 116 | return -ENOMEM; |
| 117 | |
| 118 | cpumask_copy(prof_cpu_mask, cpu_possible_mask); |
| 119 | |
| 120 | prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN); |
| 121 | if (prof_buffer) |
| 122 | return 0; |
| 123 | |
| 124 | prof_buffer = alloc_pages_exact(buffer_bytes, |
| 125 | GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN); |
| 126 | if (prof_buffer) |
| 127 | return 0; |
| 128 | |
| 129 | prof_buffer = vmalloc(buffer_bytes); |
| 130 | if (prof_buffer) |
| 131 | return 0; |
| 132 | |
| 133 | free_cpumask_var(prof_cpu_mask); |
| 134 | return -ENOMEM; |
| 135 | } |
| 136 | |
| 137 | /* Profile event notifications */ |
| 138 | |
| 139 | static BLOCKING_NOTIFIER_HEAD(task_exit_notifier); |
| 140 | static ATOMIC_NOTIFIER_HEAD(task_free_notifier); |
| 141 | static BLOCKING_NOTIFIER_HEAD(munmap_notifier); |
| 142 | |
| 143 | void profile_task_exit(struct task_struct *task) |
| 144 | { |
| 145 | blocking_notifier_call_chain(&task_exit_notifier, 0, task); |
| 146 | } |
| 147 | |
| 148 | int profile_handoff_task(struct task_struct *task) |
| 149 | { |
| 150 | int ret; |
| 151 | ret = atomic_notifier_call_chain(&task_free_notifier, 0, task); |
| 152 | return (ret == NOTIFY_OK) ? 1 : 0; |
| 153 | } |
| 154 | |
| 155 | void profile_munmap(unsigned long addr) |
| 156 | { |
| 157 | blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr); |
| 158 | } |
| 159 | |
| 160 | int task_handoff_register(struct notifier_block *n) |
| 161 | { |
| 162 | return atomic_notifier_chain_register(&task_free_notifier, n); |
| 163 | } |
| 164 | EXPORT_SYMBOL_GPL(task_handoff_register); |
| 165 | |
| 166 | int task_handoff_unregister(struct notifier_block *n) |
| 167 | { |
| 168 | return atomic_notifier_chain_unregister(&task_free_notifier, n); |
| 169 | } |
| 170 | EXPORT_SYMBOL_GPL(task_handoff_unregister); |
| 171 | |
| 172 | int profile_event_register(enum profile_type type, struct notifier_block *n) |
| 173 | { |
| 174 | int err = -EINVAL; |
| 175 | |
| 176 | switch (type) { |
| 177 | case PROFILE_TASK_EXIT: |
| 178 | err = blocking_notifier_chain_register( |
| 179 | &task_exit_notifier, n); |
| 180 | break; |
| 181 | case PROFILE_MUNMAP: |
| 182 | err = blocking_notifier_chain_register( |
| 183 | &munmap_notifier, n); |
| 184 | break; |
| 185 | } |
| 186 | |
| 187 | return err; |
| 188 | } |
| 189 | EXPORT_SYMBOL_GPL(profile_event_register); |
| 190 | |
| 191 | int profile_event_unregister(enum profile_type type, struct notifier_block *n) |
| 192 | { |
| 193 | int err = -EINVAL; |
| 194 | |
| 195 | switch (type) { |
| 196 | case PROFILE_TASK_EXIT: |
| 197 | err = blocking_notifier_chain_unregister( |
| 198 | &task_exit_notifier, n); |
| 199 | break; |
| 200 | case PROFILE_MUNMAP: |
| 201 | err = blocking_notifier_chain_unregister( |
| 202 | &munmap_notifier, n); |
| 203 | break; |
| 204 | } |
| 205 | |
| 206 | return err; |
| 207 | } |
| 208 | EXPORT_SYMBOL_GPL(profile_event_unregister); |
| 209 | |
| 210 | int register_timer_hook(int (*hook)(struct pt_regs *)) |
| 211 | { |
| 212 | if (timer_hook) |
| 213 | return -EBUSY; |
| 214 | timer_hook = hook; |
| 215 | return 0; |
| 216 | } |
| 217 | EXPORT_SYMBOL_GPL(register_timer_hook); |
| 218 | |
| 219 | void unregister_timer_hook(int (*hook)(struct pt_regs *)) |
| 220 | { |
| 221 | WARN_ON(hook != timer_hook); |
| 222 | timer_hook = NULL; |
| 223 | /* make sure all CPUs see the NULL hook */ |
| 224 | synchronize_sched(); /* Allow ongoing interrupts to complete. */ |
| 225 | } |
| 226 | EXPORT_SYMBOL_GPL(unregister_timer_hook); |
| 227 | |
| 228 | |
| 229 | #ifdef CONFIG_SMP |
| 230 | /* |
| 231 | * Each cpu has a pair of open-addressed hashtables for pending |
| 232 | * profile hits. read_profile() IPI's all cpus to request them |
| 233 | * to flip buffers and flushes their contents to prof_buffer itself. |
| 234 | * Flip requests are serialized by the profile_flip_mutex. The sole |
| 235 | * use of having a second hashtable is for avoiding cacheline |
| 236 | * contention that would otherwise happen during flushes of pending |
| 237 | * profile hits required for the accuracy of reported profile hits |
| 238 | * and so resurrect the interrupt livelock issue. |
| 239 | * |
| 240 | * The open-addressed hashtables are indexed by profile buffer slot |
| 241 | * and hold the number of pending hits to that profile buffer slot on |
| 242 | * a cpu in an entry. When the hashtable overflows, all pending hits |
| 243 | * are accounted to their corresponding profile buffer slots with |
| 244 | * atomic_add() and the hashtable emptied. As numerous pending hits |
| 245 | * may be accounted to a profile buffer slot in a hashtable entry, |
| 246 | * this amortizes a number of atomic profile buffer increments likely |
| 247 | * to be far larger than the number of entries in the hashtable, |
| 248 | * particularly given that the number of distinct profile buffer |
| 249 | * positions to which hits are accounted during short intervals (e.g. |
| 250 | * several seconds) is usually very small. Exclusion from buffer |
| 251 | * flipping is provided by interrupt disablement (note that for |
| 252 | * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from |
| 253 | * process context). |
| 254 | * The hash function is meant to be lightweight as opposed to strong, |
| 255 | * and was vaguely inspired by ppc64 firmware-supported inverted |
| 256 | * pagetable hash functions, but uses a full hashtable full of finite |
| 257 | * collision chains, not just pairs of them. |
| 258 | * |
| 259 | * -- wli |
| 260 | */ |
| 261 | static void __profile_flip_buffers(void *unused) |
| 262 | { |
| 263 | int cpu = smp_processor_id(); |
| 264 | |
| 265 | per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu); |
| 266 | } |
| 267 | |
| 268 | static void profile_flip_buffers(void) |
| 269 | { |
| 270 | int i, j, cpu; |
| 271 | |
| 272 | mutex_lock(&profile_flip_mutex); |
| 273 | j = per_cpu(cpu_profile_flip, get_cpu()); |
| 274 | put_cpu(); |
| 275 | on_each_cpu(__profile_flip_buffers, NULL, 1); |
| 276 | for_each_online_cpu(cpu) { |
| 277 | struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j]; |
| 278 | for (i = 0; i < NR_PROFILE_HIT; ++i) { |
| 279 | if (!hits[i].hits) { |
| 280 | if (hits[i].pc) |
| 281 | hits[i].pc = 0; |
| 282 | continue; |
| 283 | } |
| 284 | atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]); |
| 285 | hits[i].hits = hits[i].pc = 0; |
| 286 | } |
| 287 | } |
| 288 | mutex_unlock(&profile_flip_mutex); |
| 289 | } |
| 290 | |
| 291 | static void profile_discard_flip_buffers(void) |
| 292 | { |
| 293 | int i, cpu; |
| 294 | |
| 295 | mutex_lock(&profile_flip_mutex); |
| 296 | i = per_cpu(cpu_profile_flip, get_cpu()); |
| 297 | put_cpu(); |
| 298 | on_each_cpu(__profile_flip_buffers, NULL, 1); |
| 299 | for_each_online_cpu(cpu) { |
| 300 | struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i]; |
| 301 | memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit)); |
| 302 | } |
| 303 | mutex_unlock(&profile_flip_mutex); |
| 304 | } |
| 305 | |
| 306 | void profile_hits(int type, void *__pc, unsigned int nr_hits) |
| 307 | { |
| 308 | unsigned long primary, secondary, flags, pc = (unsigned long)__pc; |
| 309 | int i, j, cpu; |
| 310 | struct profile_hit *hits; |
| 311 | |
| 312 | if (prof_on != type || !prof_buffer) |
| 313 | return; |
| 314 | pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1); |
| 315 | i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT; |
| 316 | secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT; |
| 317 | cpu = get_cpu(); |
| 318 | hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)]; |
| 319 | if (!hits) { |
| 320 | put_cpu(); |
| 321 | return; |
| 322 | } |
| 323 | /* |
| 324 | * We buffer the global profiler buffer into a per-CPU |
| 325 | * queue and thus reduce the number of global (and possibly |
| 326 | * NUMA-alien) accesses. The write-queue is self-coalescing: |
| 327 | */ |
| 328 | local_irq_save(flags); |
| 329 | do { |
| 330 | for (j = 0; j < PROFILE_GRPSZ; ++j) { |
| 331 | if (hits[i + j].pc == pc) { |
| 332 | hits[i + j].hits += nr_hits; |
| 333 | goto out; |
| 334 | } else if (!hits[i + j].hits) { |
| 335 | hits[i + j].pc = pc; |
| 336 | hits[i + j].hits = nr_hits; |
| 337 | goto out; |
| 338 | } |
| 339 | } |
| 340 | i = (i + secondary) & (NR_PROFILE_HIT - 1); |
| 341 | } while (i != primary); |
| 342 | |
| 343 | /* |
| 344 | * Add the current hit(s) and flush the write-queue out |
| 345 | * to the global buffer: |
| 346 | */ |
| 347 | atomic_add(nr_hits, &prof_buffer[pc]); |
| 348 | for (i = 0; i < NR_PROFILE_HIT; ++i) { |
| 349 | atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]); |
| 350 | hits[i].pc = hits[i].hits = 0; |
| 351 | } |
| 352 | out: |
| 353 | local_irq_restore(flags); |
| 354 | put_cpu(); |
| 355 | } |
| 356 | |
| 357 | static int __cpuinit profile_cpu_callback(struct notifier_block *info, |
| 358 | unsigned long action, void *__cpu) |
| 359 | { |
| 360 | int node, cpu = (unsigned long)__cpu; |
| 361 | struct page *page; |
| 362 | |
| 363 | switch (action) { |
| 364 | case CPU_UP_PREPARE: |
| 365 | case CPU_UP_PREPARE_FROZEN: |
| 366 | node = cpu_to_node(cpu); |
| 367 | per_cpu(cpu_profile_flip, cpu) = 0; |
| 368 | if (!per_cpu(cpu_profile_hits, cpu)[1]) { |
| 369 | page = alloc_pages_exact_node(node, |
| 370 | GFP_KERNEL | __GFP_ZERO, |
| 371 | 0); |
| 372 | if (!page) |
| 373 | return NOTIFY_BAD; |
| 374 | per_cpu(cpu_profile_hits, cpu)[1] = page_address(page); |
| 375 | } |
| 376 | if (!per_cpu(cpu_profile_hits, cpu)[0]) { |
| 377 | page = alloc_pages_exact_node(node, |
| 378 | GFP_KERNEL | __GFP_ZERO, |
| 379 | 0); |
| 380 | if (!page) |
| 381 | goto out_free; |
| 382 | per_cpu(cpu_profile_hits, cpu)[0] = page_address(page); |
| 383 | } |
| 384 | break; |
| 385 | out_free: |
| 386 | page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]); |
| 387 | per_cpu(cpu_profile_hits, cpu)[1] = NULL; |
| 388 | __free_page(page); |
| 389 | return NOTIFY_BAD; |
| 390 | case CPU_ONLINE: |
| 391 | case CPU_ONLINE_FROZEN: |
| 392 | if (prof_cpu_mask != NULL) |
| 393 | cpumask_set_cpu(cpu, prof_cpu_mask); |
| 394 | break; |
| 395 | case CPU_UP_CANCELED: |
| 396 | case CPU_UP_CANCELED_FROZEN: |
| 397 | case CPU_DEAD: |
| 398 | case CPU_DEAD_FROZEN: |
| 399 | if (prof_cpu_mask != NULL) |
| 400 | cpumask_clear_cpu(cpu, prof_cpu_mask); |
| 401 | if (per_cpu(cpu_profile_hits, cpu)[0]) { |
| 402 | page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]); |
| 403 | per_cpu(cpu_profile_hits, cpu)[0] = NULL; |
| 404 | __free_page(page); |
| 405 | } |
| 406 | if (per_cpu(cpu_profile_hits, cpu)[1]) { |
| 407 | page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]); |
| 408 | per_cpu(cpu_profile_hits, cpu)[1] = NULL; |
| 409 | __free_page(page); |
| 410 | } |
| 411 | break; |
| 412 | } |
| 413 | return NOTIFY_OK; |
| 414 | } |
| 415 | #else /* !CONFIG_SMP */ |
| 416 | #define profile_flip_buffers() do { } while (0) |
| 417 | #define profile_discard_flip_buffers() do { } while (0) |
| 418 | #define profile_cpu_callback NULL |
| 419 | |
| 420 | void profile_hits(int type, void *__pc, unsigned int nr_hits) |
| 421 | { |
| 422 | unsigned long pc; |
| 423 | |
| 424 | if (prof_on != type || !prof_buffer) |
| 425 | return; |
| 426 | pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift; |
| 427 | atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]); |
| 428 | } |
| 429 | #endif /* !CONFIG_SMP */ |
| 430 | EXPORT_SYMBOL_GPL(profile_hits); |
| 431 | |
| 432 | void profile_tick(int type) |
| 433 | { |
| 434 | struct pt_regs *regs = get_irq_regs(); |
| 435 | |
| 436 | if (type == CPU_PROFILING && timer_hook) |
| 437 | timer_hook(regs); |
| 438 | if (!user_mode(regs) && prof_cpu_mask != NULL && |
| 439 | cpumask_test_cpu(smp_processor_id(), prof_cpu_mask)) |
| 440 | profile_hit(type, (void *)profile_pc(regs)); |
| 441 | } |
| 442 | |
| 443 | #ifdef CONFIG_PROC_FS |
| 444 | #include <linux/proc_fs.h> |
| 445 | #include <linux/seq_file.h> |
| 446 | #include <asm/uaccess.h> |
| 447 | |
| 448 | static int prof_cpu_mask_proc_show(struct seq_file *m, void *v) |
| 449 | { |
| 450 | seq_cpumask(m, prof_cpu_mask); |
| 451 | seq_putc(m, '\n'); |
| 452 | return 0; |
| 453 | } |
| 454 | |
| 455 | static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file) |
| 456 | { |
| 457 | return single_open(file, prof_cpu_mask_proc_show, NULL); |
| 458 | } |
| 459 | |
| 460 | static ssize_t prof_cpu_mask_proc_write(struct file *file, |
| 461 | const char __user *buffer, size_t count, loff_t *pos) |
| 462 | { |
| 463 | cpumask_var_t new_value; |
| 464 | int err; |
| 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(prof_cpu_mask, new_value); |
| 472 | err = count; |
| 473 | } |
| 474 | free_cpumask_var(new_value); |
| 475 | return err; |
| 476 | } |
| 477 | |
| 478 | static const struct file_operations prof_cpu_mask_proc_fops = { |
| 479 | .open = prof_cpu_mask_proc_open, |
| 480 | .read = seq_read, |
| 481 | .llseek = seq_lseek, |
| 482 | .release = single_release, |
| 483 | .write = prof_cpu_mask_proc_write, |
| 484 | }; |
| 485 | |
| 486 | void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir) |
| 487 | { |
| 488 | /* create /proc/irq/prof_cpu_mask */ |
| 489 | proc_create("prof_cpu_mask", 0600, root_irq_dir, &prof_cpu_mask_proc_fops); |
| 490 | } |
| 491 | |
| 492 | /* |
| 493 | * This function accesses profiling information. The returned data is |
| 494 | * binary: the sampling step and the actual contents of the profile |
| 495 | * buffer. Use of the program readprofile is recommended in order to |
| 496 | * get meaningful info out of these data. |
| 497 | */ |
| 498 | static ssize_t |
| 499 | read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| 500 | { |
| 501 | unsigned long p = *ppos; |
| 502 | ssize_t read; |
| 503 | char *pnt; |
| 504 | unsigned int sample_step = 1 << prof_shift; |
| 505 | |
| 506 | profile_flip_buffers(); |
| 507 | if (p >= (prof_len+1)*sizeof(unsigned int)) |
| 508 | return 0; |
| 509 | if (count > (prof_len+1)*sizeof(unsigned int) - p) |
| 510 | count = (prof_len+1)*sizeof(unsigned int) - p; |
| 511 | read = 0; |
| 512 | |
| 513 | while (p < sizeof(unsigned int) && count > 0) { |
| 514 | if (put_user(*((char *)(&sample_step)+p), buf)) |
| 515 | return -EFAULT; |
| 516 | buf++; p++; count--; read++; |
| 517 | } |
| 518 | pnt = (char *)prof_buffer + p - sizeof(atomic_t); |
| 519 | if (copy_to_user(buf, (void *)pnt, count)) |
| 520 | return -EFAULT; |
| 521 | read += count; |
| 522 | *ppos += read; |
| 523 | return read; |
| 524 | } |
| 525 | |
| 526 | /* |
| 527 | * Writing to /proc/profile resets the counters |
| 528 | * |
| 529 | * Writing a 'profiling multiplier' value into it also re-sets the profiling |
| 530 | * interrupt frequency, on architectures that support this. |
| 531 | */ |
| 532 | static ssize_t write_profile(struct file *file, const char __user *buf, |
| 533 | size_t count, loff_t *ppos) |
| 534 | { |
| 535 | #ifdef CONFIG_SMP |
| 536 | extern int setup_profiling_timer(unsigned int multiplier); |
| 537 | |
| 538 | if (count == sizeof(int)) { |
| 539 | unsigned int multiplier; |
| 540 | |
| 541 | if (copy_from_user(&multiplier, buf, sizeof(int))) |
| 542 | return -EFAULT; |
| 543 | |
| 544 | if (setup_profiling_timer(multiplier)) |
| 545 | return -EINVAL; |
| 546 | } |
| 547 | #endif |
| 548 | profile_discard_flip_buffers(); |
| 549 | memset(prof_buffer, 0, prof_len * sizeof(atomic_t)); |
| 550 | return count; |
| 551 | } |
| 552 | |
| 553 | static const struct file_operations proc_profile_operations = { |
| 554 | .read = read_profile, |
| 555 | .write = write_profile, |
| 556 | }; |
| 557 | |
| 558 | #ifdef CONFIG_SMP |
| 559 | static void profile_nop(void *unused) |
| 560 | { |
| 561 | } |
| 562 | |
| 563 | static int create_hash_tables(void) |
| 564 | { |
| 565 | int cpu; |
| 566 | |
| 567 | for_each_online_cpu(cpu) { |
| 568 | int node = cpu_to_node(cpu); |
| 569 | struct page *page; |
| 570 | |
| 571 | page = alloc_pages_exact_node(node, |
| 572 | GFP_KERNEL | __GFP_ZERO | GFP_THISNODE, |
| 573 | 0); |
| 574 | if (!page) |
| 575 | goto out_cleanup; |
| 576 | per_cpu(cpu_profile_hits, cpu)[1] |
| 577 | = (struct profile_hit *)page_address(page); |
| 578 | page = alloc_pages_exact_node(node, |
| 579 | GFP_KERNEL | __GFP_ZERO | GFP_THISNODE, |
| 580 | 0); |
| 581 | if (!page) |
| 582 | goto out_cleanup; |
| 583 | per_cpu(cpu_profile_hits, cpu)[0] |
| 584 | = (struct profile_hit *)page_address(page); |
| 585 | } |
| 586 | return 0; |
| 587 | out_cleanup: |
| 588 | prof_on = 0; |
| 589 | smp_mb(); |
| 590 | on_each_cpu(profile_nop, NULL, 1); |
| 591 | for_each_online_cpu(cpu) { |
| 592 | struct page *page; |
| 593 | |
| 594 | if (per_cpu(cpu_profile_hits, cpu)[0]) { |
| 595 | page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]); |
| 596 | per_cpu(cpu_profile_hits, cpu)[0] = NULL; |
| 597 | __free_page(page); |
| 598 | } |
| 599 | if (per_cpu(cpu_profile_hits, cpu)[1]) { |
| 600 | page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]); |
| 601 | per_cpu(cpu_profile_hits, cpu)[1] = NULL; |
| 602 | __free_page(page); |
| 603 | } |
| 604 | } |
| 605 | return -1; |
| 606 | } |
| 607 | #else |
| 608 | #define create_hash_tables() ({ 0; }) |
| 609 | #endif |
| 610 | |
| 611 | int __ref create_proc_profile(void) /* false positive from hotcpu_notifier */ |
| 612 | { |
| 613 | struct proc_dir_entry *entry; |
| 614 | |
| 615 | if (!prof_on) |
| 616 | return 0; |
| 617 | if (create_hash_tables()) |
| 618 | return -ENOMEM; |
| 619 | entry = proc_create("profile", S_IWUSR | S_IRUGO, |
| 620 | NULL, &proc_profile_operations); |
| 621 | if (!entry) |
| 622 | return 0; |
| 623 | entry->size = (1+prof_len) * sizeof(atomic_t); |
| 624 | hotcpu_notifier(profile_cpu_callback, 0); |
| 625 | return 0; |
| 626 | } |
| 627 | module_init(create_proc_profile); |
| 628 | #endif /* CONFIG_PROC_FS */ |