Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Performance counter core code |
| 3 | * |
| 4 | * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de> |
| 5 | * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar |
| 6 | * |
| 7 | * For licencing details see kernel-base/COPYING |
| 8 | */ |
| 9 | |
| 10 | #include <linux/fs.h> |
| 11 | #include <linux/cpu.h> |
| 12 | #include <linux/smp.h> |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 13 | #include <linux/file.h> |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 14 | #include <linux/poll.h> |
| 15 | #include <linux/sysfs.h> |
| 16 | #include <linux/ptrace.h> |
| 17 | #include <linux/percpu.h> |
| 18 | #include <linux/uaccess.h> |
| 19 | #include <linux/syscalls.h> |
| 20 | #include <linux/anon_inodes.h> |
| 21 | #include <linux/perf_counter.h> |
| 22 | |
| 23 | /* |
| 24 | * Each CPU has a list of per CPU counters: |
| 25 | */ |
| 26 | DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context); |
| 27 | |
| 28 | int perf_max_counters __read_mostly; |
| 29 | static int perf_reserved_percpu __read_mostly; |
| 30 | static int perf_overcommit __read_mostly = 1; |
| 31 | |
| 32 | /* |
| 33 | * Mutex for (sysadmin-configurable) counter reservations: |
| 34 | */ |
| 35 | static DEFINE_MUTEX(perf_resource_mutex); |
| 36 | |
| 37 | /* |
| 38 | * Architecture provided APIs - weak aliases: |
| 39 | */ |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 40 | extern __weak const struct hw_perf_counter_ops * |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 41 | hw_perf_counter_init(struct perf_counter *counter) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 42 | { |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 43 | return ERR_PTR(-EINVAL); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 44 | } |
| 45 | |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 46 | u64 __weak hw_perf_save_disable(void) { return 0; } |
Ingo Molnar | ee06094 | 2008-12-13 09:00:03 +0100 | [diff] [blame] | 47 | void __weak hw_perf_restore(u64 ctrl) { } |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 48 | void __weak hw_perf_counter_setup(void) { } |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 49 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 50 | static void |
| 51 | list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx) |
| 52 | { |
| 53 | struct perf_counter *group_leader = counter->group_leader; |
| 54 | |
| 55 | /* |
| 56 | * Depending on whether it is a standalone or sibling counter, |
| 57 | * add it straight to the context's counter list, or to the group |
| 58 | * leader's sibling list: |
| 59 | */ |
| 60 | if (counter->group_leader == counter) |
| 61 | list_add_tail(&counter->list_entry, &ctx->counter_list); |
| 62 | else |
| 63 | list_add_tail(&counter->list_entry, &group_leader->sibling_list); |
| 64 | } |
| 65 | |
| 66 | static void |
| 67 | list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx) |
| 68 | { |
| 69 | struct perf_counter *sibling, *tmp; |
| 70 | |
| 71 | list_del_init(&counter->list_entry); |
| 72 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 73 | /* |
| 74 | * If this was a group counter with sibling counters then |
| 75 | * upgrade the siblings to singleton counters by adding them |
| 76 | * to the context list directly: |
| 77 | */ |
| 78 | list_for_each_entry_safe(sibling, tmp, |
| 79 | &counter->sibling_list, list_entry) { |
| 80 | |
| 81 | list_del_init(&sibling->list_entry); |
| 82 | list_add_tail(&sibling->list_entry, &ctx->counter_list); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 83 | sibling->group_leader = sibling; |
| 84 | } |
| 85 | } |
| 86 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 87 | /* |
| 88 | * Cross CPU call to remove a performance counter |
| 89 | * |
| 90 | * We disable the counter on the hardware level first. After that we |
| 91 | * remove it from the context list. |
| 92 | */ |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 93 | static void __perf_counter_remove_from_context(void *info) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 94 | { |
| 95 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| 96 | struct perf_counter *counter = info; |
| 97 | struct perf_counter_context *ctx = counter->ctx; |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 98 | unsigned long flags; |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 99 | u64 perf_flags; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 100 | |
| 101 | /* |
| 102 | * If this is a task context, we need to check whether it is |
| 103 | * the current task context of this cpu. If not it has been |
| 104 | * scheduled out before the smp call arrived. |
| 105 | */ |
| 106 | if (ctx->task && cpuctx->task_ctx != ctx) |
| 107 | return; |
| 108 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 109 | spin_lock_irqsave(&ctx->lock, flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 110 | |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 111 | if (counter->state == PERF_COUNTER_STATE_ACTIVE) { |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 112 | counter->hw_ops->hw_perf_counter_disable(counter); |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 113 | counter->state = PERF_COUNTER_STATE_INACTIVE; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 114 | ctx->nr_active--; |
| 115 | cpuctx->active_oncpu--; |
| 116 | counter->task = NULL; |
| 117 | } |
| 118 | ctx->nr_counters--; |
| 119 | |
| 120 | /* |
| 121 | * Protect the list operation against NMI by disabling the |
| 122 | * counters on a global level. NOP for non NMI based counters. |
| 123 | */ |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 124 | perf_flags = hw_perf_save_disable(); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 125 | list_del_counter(counter, ctx); |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 126 | hw_perf_restore(perf_flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 127 | |
| 128 | if (!ctx->task) { |
| 129 | /* |
| 130 | * Allow more per task counters with respect to the |
| 131 | * reservation: |
| 132 | */ |
| 133 | cpuctx->max_pertask = |
| 134 | min(perf_max_counters - ctx->nr_counters, |
| 135 | perf_max_counters - perf_reserved_percpu); |
| 136 | } |
| 137 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 138 | spin_unlock_irqrestore(&ctx->lock, flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 139 | } |
| 140 | |
| 141 | |
| 142 | /* |
| 143 | * Remove the counter from a task's (or a CPU's) list of counters. |
| 144 | * |
| 145 | * Must be called with counter->mutex held. |
| 146 | * |
| 147 | * CPU counters are removed with a smp call. For task counters we only |
| 148 | * call when the task is on a CPU. |
| 149 | */ |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 150 | static void perf_counter_remove_from_context(struct perf_counter *counter) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 151 | { |
| 152 | struct perf_counter_context *ctx = counter->ctx; |
| 153 | struct task_struct *task = ctx->task; |
| 154 | |
| 155 | if (!task) { |
| 156 | /* |
| 157 | * Per cpu counters are removed via an smp call and |
| 158 | * the removal is always sucessful. |
| 159 | */ |
| 160 | smp_call_function_single(counter->cpu, |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 161 | __perf_counter_remove_from_context, |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 162 | counter, 1); |
| 163 | return; |
| 164 | } |
| 165 | |
| 166 | retry: |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 167 | task_oncpu_function_call(task, __perf_counter_remove_from_context, |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 168 | counter); |
| 169 | |
| 170 | spin_lock_irq(&ctx->lock); |
| 171 | /* |
| 172 | * If the context is active we need to retry the smp call. |
| 173 | */ |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 174 | if (ctx->nr_active && !list_empty(&counter->list_entry)) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 175 | spin_unlock_irq(&ctx->lock); |
| 176 | goto retry; |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * The lock prevents that this context is scheduled in so we |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 181 | * can remove the counter safely, if the call above did not |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 182 | * succeed. |
| 183 | */ |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 184 | if (!list_empty(&counter->list_entry)) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 185 | ctx->nr_counters--; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 186 | list_del_counter(counter, ctx); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 187 | counter->task = NULL; |
| 188 | } |
| 189 | spin_unlock_irq(&ctx->lock); |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * Cross CPU call to install and enable a preformance counter |
| 194 | */ |
| 195 | static void __perf_install_in_context(void *info) |
| 196 | { |
| 197 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| 198 | struct perf_counter *counter = info; |
| 199 | struct perf_counter_context *ctx = counter->ctx; |
| 200 | int cpu = smp_processor_id(); |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 201 | unsigned long flags; |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 202 | u64 perf_flags; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 203 | |
| 204 | /* |
| 205 | * If this is a task context, we need to check whether it is |
| 206 | * the current task context of this cpu. If not it has been |
| 207 | * scheduled out before the smp call arrived. |
| 208 | */ |
| 209 | if (ctx->task && cpuctx->task_ctx != ctx) |
| 210 | return; |
| 211 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 212 | spin_lock_irqsave(&ctx->lock, flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 213 | |
| 214 | /* |
| 215 | * Protect the list operation against NMI by disabling the |
| 216 | * counters on a global level. NOP for non NMI based counters. |
| 217 | */ |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 218 | perf_flags = hw_perf_save_disable(); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 219 | list_add_counter(counter, ctx); |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 220 | hw_perf_restore(perf_flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 221 | |
| 222 | ctx->nr_counters++; |
| 223 | |
| 224 | if (cpuctx->active_oncpu < perf_max_counters) { |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 225 | counter->state = PERF_COUNTER_STATE_ACTIVE; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 226 | counter->oncpu = cpu; |
| 227 | ctx->nr_active++; |
| 228 | cpuctx->active_oncpu++; |
Ingo Molnar | ee06094 | 2008-12-13 09:00:03 +0100 | [diff] [blame] | 229 | counter->hw_ops->hw_perf_counter_enable(counter); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 230 | } |
| 231 | |
| 232 | if (!ctx->task && cpuctx->max_pertask) |
| 233 | cpuctx->max_pertask--; |
| 234 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 235 | spin_unlock_irqrestore(&ctx->lock, flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 236 | } |
| 237 | |
| 238 | /* |
| 239 | * Attach a performance counter to a context |
| 240 | * |
| 241 | * First we add the counter to the list with the hardware enable bit |
| 242 | * in counter->hw_config cleared. |
| 243 | * |
| 244 | * If the counter is attached to a task which is on a CPU we use a smp |
| 245 | * call to enable it in the task context. The task might have been |
| 246 | * scheduled away, but we check this in the smp call again. |
| 247 | */ |
| 248 | static void |
| 249 | perf_install_in_context(struct perf_counter_context *ctx, |
| 250 | struct perf_counter *counter, |
| 251 | int cpu) |
| 252 | { |
| 253 | struct task_struct *task = ctx->task; |
| 254 | |
| 255 | counter->ctx = ctx; |
| 256 | if (!task) { |
| 257 | /* |
| 258 | * Per cpu counters are installed via an smp call and |
| 259 | * the install is always sucessful. |
| 260 | */ |
| 261 | smp_call_function_single(cpu, __perf_install_in_context, |
| 262 | counter, 1); |
| 263 | return; |
| 264 | } |
| 265 | |
| 266 | counter->task = task; |
| 267 | retry: |
| 268 | task_oncpu_function_call(task, __perf_install_in_context, |
| 269 | counter); |
| 270 | |
| 271 | spin_lock_irq(&ctx->lock); |
| 272 | /* |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 273 | * we need to retry the smp call. |
| 274 | */ |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 275 | if (ctx->nr_active && list_empty(&counter->list_entry)) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 276 | spin_unlock_irq(&ctx->lock); |
| 277 | goto retry; |
| 278 | } |
| 279 | |
| 280 | /* |
| 281 | * The lock prevents that this context is scheduled in so we |
| 282 | * can add the counter safely, if it the call above did not |
| 283 | * succeed. |
| 284 | */ |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 285 | if (list_empty(&counter->list_entry)) { |
| 286 | list_add_counter(counter, ctx); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 287 | ctx->nr_counters++; |
| 288 | } |
| 289 | spin_unlock_irq(&ctx->lock); |
| 290 | } |
| 291 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 292 | static void |
| 293 | counter_sched_out(struct perf_counter *counter, |
| 294 | struct perf_cpu_context *cpuctx, |
| 295 | struct perf_counter_context *ctx) |
| 296 | { |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 297 | if (counter->state != PERF_COUNTER_STATE_ACTIVE) |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 298 | return; |
| 299 | |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 300 | counter->hw_ops->hw_perf_counter_disable(counter); |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 301 | counter->state = PERF_COUNTER_STATE_INACTIVE; |
| 302 | counter->oncpu = -1; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 303 | |
| 304 | cpuctx->active_oncpu--; |
| 305 | ctx->nr_active--; |
| 306 | } |
| 307 | |
| 308 | static void |
| 309 | group_sched_out(struct perf_counter *group_counter, |
| 310 | struct perf_cpu_context *cpuctx, |
| 311 | struct perf_counter_context *ctx) |
| 312 | { |
| 313 | struct perf_counter *counter; |
| 314 | |
| 315 | counter_sched_out(group_counter, cpuctx, ctx); |
| 316 | |
| 317 | /* |
| 318 | * Schedule out siblings (if any): |
| 319 | */ |
| 320 | list_for_each_entry(counter, &group_counter->sibling_list, list_entry) |
| 321 | counter_sched_out(counter, cpuctx, ctx); |
| 322 | } |
| 323 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 324 | /* |
| 325 | * Called from scheduler to remove the counters of the current task, |
| 326 | * with interrupts disabled. |
| 327 | * |
| 328 | * We stop each counter and update the counter value in counter->count. |
| 329 | * |
| 330 | * This does not protect us against NMI, but hw_perf_counter_disable() |
| 331 | * sets the disabled bit in the control field of counter _before_ |
| 332 | * accessing the counter control register. If a NMI hits, then it will |
| 333 | * not restart the counter. |
| 334 | */ |
| 335 | void perf_counter_task_sched_out(struct task_struct *task, int cpu) |
| 336 | { |
| 337 | struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); |
| 338 | struct perf_counter_context *ctx = &task->perf_counter_ctx; |
| 339 | struct perf_counter *counter; |
| 340 | |
| 341 | if (likely(!cpuctx->task_ctx)) |
| 342 | return; |
| 343 | |
| 344 | spin_lock(&ctx->lock); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 345 | if (ctx->nr_active) { |
| 346 | list_for_each_entry(counter, &ctx->counter_list, list_entry) |
| 347 | group_sched_out(counter, cpuctx, ctx); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 348 | } |
| 349 | spin_unlock(&ctx->lock); |
| 350 | cpuctx->task_ctx = NULL; |
| 351 | } |
| 352 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 353 | static void |
| 354 | counter_sched_in(struct perf_counter *counter, |
| 355 | struct perf_cpu_context *cpuctx, |
| 356 | struct perf_counter_context *ctx, |
| 357 | int cpu) |
| 358 | { |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 359 | if (counter->state == PERF_COUNTER_STATE_OFF) |
Ingo Molnar | 1d1c7dd | 2008-12-11 14:59:31 +0100 | [diff] [blame] | 360 | return; |
| 361 | |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 362 | counter->hw_ops->hw_perf_counter_enable(counter); |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 363 | counter->state = PERF_COUNTER_STATE_ACTIVE; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 364 | counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */ |
| 365 | |
| 366 | cpuctx->active_oncpu++; |
| 367 | ctx->nr_active++; |
| 368 | } |
| 369 | |
| 370 | static void |
| 371 | group_sched_in(struct perf_counter *group_counter, |
| 372 | struct perf_cpu_context *cpuctx, |
| 373 | struct perf_counter_context *ctx, |
| 374 | int cpu) |
| 375 | { |
| 376 | struct perf_counter *counter; |
| 377 | |
| 378 | counter_sched_in(group_counter, cpuctx, ctx, cpu); |
| 379 | |
| 380 | /* |
| 381 | * Schedule in siblings as one group (if any): |
| 382 | */ |
| 383 | list_for_each_entry(counter, &group_counter->sibling_list, list_entry) |
| 384 | counter_sched_in(counter, cpuctx, ctx, cpu); |
| 385 | } |
| 386 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 387 | /* |
| 388 | * Called from scheduler to add the counters of the current task |
| 389 | * with interrupts disabled. |
| 390 | * |
| 391 | * We restore the counter value and then enable it. |
| 392 | * |
| 393 | * This does not protect us against NMI, but hw_perf_counter_enable() |
| 394 | * sets the enabled bit in the control field of counter _before_ |
| 395 | * accessing the counter control register. If a NMI hits, then it will |
| 396 | * keep the counter running. |
| 397 | */ |
| 398 | void perf_counter_task_sched_in(struct task_struct *task, int cpu) |
| 399 | { |
| 400 | struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); |
| 401 | struct perf_counter_context *ctx = &task->perf_counter_ctx; |
| 402 | struct perf_counter *counter; |
| 403 | |
| 404 | if (likely(!ctx->nr_counters)) |
| 405 | return; |
| 406 | |
| 407 | spin_lock(&ctx->lock); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 408 | list_for_each_entry(counter, &ctx->counter_list, list_entry) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 409 | if (ctx->nr_active == cpuctx->max_pertask) |
| 410 | break; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 411 | |
| 412 | /* |
| 413 | * Listen to the 'cpu' scheduling filter constraint |
| 414 | * of counters: |
| 415 | */ |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 416 | if (counter->cpu != -1 && counter->cpu != cpu) |
| 417 | continue; |
| 418 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 419 | group_sched_in(counter, cpuctx, ctx, cpu); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 420 | } |
| 421 | spin_unlock(&ctx->lock); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 422 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 423 | cpuctx->task_ctx = ctx; |
| 424 | } |
| 425 | |
Ingo Molnar | 1d1c7dd | 2008-12-11 14:59:31 +0100 | [diff] [blame] | 426 | int perf_counter_task_disable(void) |
| 427 | { |
| 428 | struct task_struct *curr = current; |
| 429 | struct perf_counter_context *ctx = &curr->perf_counter_ctx; |
| 430 | struct perf_counter *counter; |
| 431 | u64 perf_flags; |
| 432 | int cpu; |
| 433 | |
| 434 | if (likely(!ctx->nr_counters)) |
| 435 | return 0; |
| 436 | |
| 437 | local_irq_disable(); |
| 438 | cpu = smp_processor_id(); |
| 439 | |
| 440 | perf_counter_task_sched_out(curr, cpu); |
| 441 | |
| 442 | spin_lock(&ctx->lock); |
| 443 | |
| 444 | /* |
| 445 | * Disable all the counters: |
| 446 | */ |
| 447 | perf_flags = hw_perf_save_disable(); |
| 448 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 449 | list_for_each_entry(counter, &ctx->counter_list, list_entry) |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 450 | counter->state = PERF_COUNTER_STATE_OFF; |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 451 | |
Ingo Molnar | 1d1c7dd | 2008-12-11 14:59:31 +0100 | [diff] [blame] | 452 | hw_perf_restore(perf_flags); |
| 453 | |
| 454 | spin_unlock(&ctx->lock); |
| 455 | |
| 456 | local_irq_enable(); |
| 457 | |
| 458 | return 0; |
| 459 | } |
| 460 | |
| 461 | int perf_counter_task_enable(void) |
| 462 | { |
| 463 | struct task_struct *curr = current; |
| 464 | struct perf_counter_context *ctx = &curr->perf_counter_ctx; |
| 465 | struct perf_counter *counter; |
| 466 | u64 perf_flags; |
| 467 | int cpu; |
| 468 | |
| 469 | if (likely(!ctx->nr_counters)) |
| 470 | return 0; |
| 471 | |
| 472 | local_irq_disable(); |
| 473 | cpu = smp_processor_id(); |
| 474 | |
| 475 | spin_lock(&ctx->lock); |
| 476 | |
| 477 | /* |
| 478 | * Disable all the counters: |
| 479 | */ |
| 480 | perf_flags = hw_perf_save_disable(); |
| 481 | |
| 482 | list_for_each_entry(counter, &ctx->counter_list, list_entry) { |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 483 | if (counter->state != PERF_COUNTER_STATE_OFF) |
Ingo Molnar | 1d1c7dd | 2008-12-11 14:59:31 +0100 | [diff] [blame] | 484 | continue; |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 485 | counter->state = PERF_COUNTER_STATE_INACTIVE; |
Ingo Molnar | 1d1c7dd | 2008-12-11 14:59:31 +0100 | [diff] [blame] | 486 | } |
| 487 | hw_perf_restore(perf_flags); |
| 488 | |
| 489 | spin_unlock(&ctx->lock); |
| 490 | |
| 491 | perf_counter_task_sched_in(curr, cpu); |
| 492 | |
| 493 | local_irq_enable(); |
| 494 | |
| 495 | return 0; |
| 496 | } |
| 497 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 498 | void perf_counter_task_tick(struct task_struct *curr, int cpu) |
| 499 | { |
| 500 | struct perf_counter_context *ctx = &curr->perf_counter_ctx; |
| 501 | struct perf_counter *counter; |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 502 | u64 perf_flags; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 503 | |
| 504 | if (likely(!ctx->nr_counters)) |
| 505 | return; |
| 506 | |
| 507 | perf_counter_task_sched_out(curr, cpu); |
| 508 | |
| 509 | spin_lock(&ctx->lock); |
| 510 | |
| 511 | /* |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 512 | * Rotate the first entry last (works just fine for group counters too): |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 513 | */ |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 514 | perf_flags = hw_perf_save_disable(); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 515 | list_for_each_entry(counter, &ctx->counter_list, list_entry) { |
| 516 | list_del(&counter->list_entry); |
| 517 | list_add_tail(&counter->list_entry, &ctx->counter_list); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 518 | break; |
| 519 | } |
Ingo Molnar | 01b2838 | 2008-12-11 13:45:51 +0100 | [diff] [blame] | 520 | hw_perf_restore(perf_flags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 521 | |
| 522 | spin_unlock(&ctx->lock); |
| 523 | |
| 524 | perf_counter_task_sched_in(curr, cpu); |
| 525 | } |
| 526 | |
| 527 | /* |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 528 | * Cross CPU call to read the hardware counter |
| 529 | */ |
| 530 | static void __hw_perf_counter_read(void *info) |
| 531 | { |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 532 | struct perf_counter *counter = info; |
| 533 | |
| 534 | counter->hw_ops->hw_perf_counter_read(counter); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 535 | } |
| 536 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 537 | static u64 perf_counter_read(struct perf_counter *counter) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 538 | { |
| 539 | /* |
| 540 | * If counter is enabled and currently active on a CPU, update the |
| 541 | * value in the counter structure: |
| 542 | */ |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 543 | if (counter->state == PERF_COUNTER_STATE_ACTIVE) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 544 | smp_call_function_single(counter->oncpu, |
| 545 | __hw_perf_counter_read, counter, 1); |
| 546 | } |
| 547 | |
Ingo Molnar | ee06094 | 2008-12-13 09:00:03 +0100 | [diff] [blame] | 548 | return atomic64_read(&counter->count); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 549 | } |
| 550 | |
| 551 | /* |
| 552 | * Cross CPU call to switch performance data pointers |
| 553 | */ |
| 554 | static void __perf_switch_irq_data(void *info) |
| 555 | { |
| 556 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| 557 | struct perf_counter *counter = info; |
| 558 | struct perf_counter_context *ctx = counter->ctx; |
| 559 | struct perf_data *oldirqdata = counter->irqdata; |
| 560 | |
| 561 | /* |
| 562 | * If this is a task context, we need to check whether it is |
| 563 | * the current task context of this cpu. If not it has been |
| 564 | * scheduled out before the smp call arrived. |
| 565 | */ |
| 566 | if (ctx->task) { |
| 567 | if (cpuctx->task_ctx != ctx) |
| 568 | return; |
| 569 | spin_lock(&ctx->lock); |
| 570 | } |
| 571 | |
| 572 | /* Change the pointer NMI safe */ |
| 573 | atomic_long_set((atomic_long_t *)&counter->irqdata, |
| 574 | (unsigned long) counter->usrdata); |
| 575 | counter->usrdata = oldirqdata; |
| 576 | |
| 577 | if (ctx->task) |
| 578 | spin_unlock(&ctx->lock); |
| 579 | } |
| 580 | |
| 581 | static struct perf_data *perf_switch_irq_data(struct perf_counter *counter) |
| 582 | { |
| 583 | struct perf_counter_context *ctx = counter->ctx; |
| 584 | struct perf_data *oldirqdata = counter->irqdata; |
| 585 | struct task_struct *task = ctx->task; |
| 586 | |
| 587 | if (!task) { |
| 588 | smp_call_function_single(counter->cpu, |
| 589 | __perf_switch_irq_data, |
| 590 | counter, 1); |
| 591 | return counter->usrdata; |
| 592 | } |
| 593 | |
| 594 | retry: |
| 595 | spin_lock_irq(&ctx->lock); |
Ingo Molnar | 6a93070 | 2008-12-11 15:17:03 +0100 | [diff] [blame] | 596 | if (counter->state != PERF_COUNTER_STATE_ACTIVE) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 597 | counter->irqdata = counter->usrdata; |
| 598 | counter->usrdata = oldirqdata; |
| 599 | spin_unlock_irq(&ctx->lock); |
| 600 | return oldirqdata; |
| 601 | } |
| 602 | spin_unlock_irq(&ctx->lock); |
| 603 | task_oncpu_function_call(task, __perf_switch_irq_data, counter); |
| 604 | /* Might have failed, because task was scheduled out */ |
| 605 | if (counter->irqdata == oldirqdata) |
| 606 | goto retry; |
| 607 | |
| 608 | return counter->usrdata; |
| 609 | } |
| 610 | |
| 611 | static void put_context(struct perf_counter_context *ctx) |
| 612 | { |
| 613 | if (ctx->task) |
| 614 | put_task_struct(ctx->task); |
| 615 | } |
| 616 | |
| 617 | static struct perf_counter_context *find_get_context(pid_t pid, int cpu) |
| 618 | { |
| 619 | struct perf_cpu_context *cpuctx; |
| 620 | struct perf_counter_context *ctx; |
| 621 | struct task_struct *task; |
| 622 | |
| 623 | /* |
| 624 | * If cpu is not a wildcard then this is a percpu counter: |
| 625 | */ |
| 626 | if (cpu != -1) { |
| 627 | /* Must be root to operate on a CPU counter: */ |
| 628 | if (!capable(CAP_SYS_ADMIN)) |
| 629 | return ERR_PTR(-EACCES); |
| 630 | |
| 631 | if (cpu < 0 || cpu > num_possible_cpus()) |
| 632 | return ERR_PTR(-EINVAL); |
| 633 | |
| 634 | /* |
| 635 | * We could be clever and allow to attach a counter to an |
| 636 | * offline CPU and activate it when the CPU comes up, but |
| 637 | * that's for later. |
| 638 | */ |
| 639 | if (!cpu_isset(cpu, cpu_online_map)) |
| 640 | return ERR_PTR(-ENODEV); |
| 641 | |
| 642 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
| 643 | ctx = &cpuctx->ctx; |
| 644 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 645 | return ctx; |
| 646 | } |
| 647 | |
| 648 | rcu_read_lock(); |
| 649 | if (!pid) |
| 650 | task = current; |
| 651 | else |
| 652 | task = find_task_by_vpid(pid); |
| 653 | if (task) |
| 654 | get_task_struct(task); |
| 655 | rcu_read_unlock(); |
| 656 | |
| 657 | if (!task) |
| 658 | return ERR_PTR(-ESRCH); |
| 659 | |
| 660 | ctx = &task->perf_counter_ctx; |
| 661 | ctx->task = task; |
| 662 | |
| 663 | /* Reuse ptrace permission checks for now. */ |
| 664 | if (!ptrace_may_access(task, PTRACE_MODE_READ)) { |
| 665 | put_context(ctx); |
| 666 | return ERR_PTR(-EACCES); |
| 667 | } |
| 668 | |
| 669 | return ctx; |
| 670 | } |
| 671 | |
| 672 | /* |
| 673 | * Called when the last reference to the file is gone. |
| 674 | */ |
| 675 | static int perf_release(struct inode *inode, struct file *file) |
| 676 | { |
| 677 | struct perf_counter *counter = file->private_data; |
| 678 | struct perf_counter_context *ctx = counter->ctx; |
| 679 | |
| 680 | file->private_data = NULL; |
| 681 | |
| 682 | mutex_lock(&counter->mutex); |
| 683 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 684 | perf_counter_remove_from_context(counter); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 685 | put_context(ctx); |
| 686 | |
| 687 | mutex_unlock(&counter->mutex); |
| 688 | |
| 689 | kfree(counter); |
| 690 | |
| 691 | return 0; |
| 692 | } |
| 693 | |
| 694 | /* |
| 695 | * Read the performance counter - simple non blocking version for now |
| 696 | */ |
| 697 | static ssize_t |
| 698 | perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count) |
| 699 | { |
| 700 | u64 cntval; |
| 701 | |
| 702 | if (count != sizeof(cntval)) |
| 703 | return -EINVAL; |
| 704 | |
| 705 | mutex_lock(&counter->mutex); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 706 | cntval = perf_counter_read(counter); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 707 | mutex_unlock(&counter->mutex); |
| 708 | |
| 709 | return put_user(cntval, (u64 __user *) buf) ? -EFAULT : sizeof(cntval); |
| 710 | } |
| 711 | |
| 712 | static ssize_t |
| 713 | perf_copy_usrdata(struct perf_data *usrdata, char __user *buf, size_t count) |
| 714 | { |
| 715 | if (!usrdata->len) |
| 716 | return 0; |
| 717 | |
| 718 | count = min(count, (size_t)usrdata->len); |
| 719 | if (copy_to_user(buf, usrdata->data + usrdata->rd_idx, count)) |
| 720 | return -EFAULT; |
| 721 | |
| 722 | /* Adjust the counters */ |
| 723 | usrdata->len -= count; |
| 724 | if (!usrdata->len) |
| 725 | usrdata->rd_idx = 0; |
| 726 | else |
| 727 | usrdata->rd_idx += count; |
| 728 | |
| 729 | return count; |
| 730 | } |
| 731 | |
| 732 | static ssize_t |
| 733 | perf_read_irq_data(struct perf_counter *counter, |
| 734 | char __user *buf, |
| 735 | size_t count, |
| 736 | int nonblocking) |
| 737 | { |
| 738 | struct perf_data *irqdata, *usrdata; |
| 739 | DECLARE_WAITQUEUE(wait, current); |
| 740 | ssize_t res; |
| 741 | |
| 742 | irqdata = counter->irqdata; |
| 743 | usrdata = counter->usrdata; |
| 744 | |
| 745 | if (usrdata->len + irqdata->len >= count) |
| 746 | goto read_pending; |
| 747 | |
| 748 | if (nonblocking) |
| 749 | return -EAGAIN; |
| 750 | |
| 751 | spin_lock_irq(&counter->waitq.lock); |
| 752 | __add_wait_queue(&counter->waitq, &wait); |
| 753 | for (;;) { |
| 754 | set_current_state(TASK_INTERRUPTIBLE); |
| 755 | if (usrdata->len + irqdata->len >= count) |
| 756 | break; |
| 757 | |
| 758 | if (signal_pending(current)) |
| 759 | break; |
| 760 | |
| 761 | spin_unlock_irq(&counter->waitq.lock); |
| 762 | schedule(); |
| 763 | spin_lock_irq(&counter->waitq.lock); |
| 764 | } |
| 765 | __remove_wait_queue(&counter->waitq, &wait); |
| 766 | __set_current_state(TASK_RUNNING); |
| 767 | spin_unlock_irq(&counter->waitq.lock); |
| 768 | |
| 769 | if (usrdata->len + irqdata->len < count) |
| 770 | return -ERESTARTSYS; |
| 771 | read_pending: |
| 772 | mutex_lock(&counter->mutex); |
| 773 | |
| 774 | /* Drain pending data first: */ |
| 775 | res = perf_copy_usrdata(usrdata, buf, count); |
| 776 | if (res < 0 || res == count) |
| 777 | goto out; |
| 778 | |
| 779 | /* Switch irq buffer: */ |
| 780 | usrdata = perf_switch_irq_data(counter); |
| 781 | if (perf_copy_usrdata(usrdata, buf + res, count - res) < 0) { |
| 782 | if (!res) |
| 783 | res = -EFAULT; |
| 784 | } else { |
| 785 | res = count; |
| 786 | } |
| 787 | out: |
| 788 | mutex_unlock(&counter->mutex); |
| 789 | |
| 790 | return res; |
| 791 | } |
| 792 | |
| 793 | static ssize_t |
| 794 | perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| 795 | { |
| 796 | struct perf_counter *counter = file->private_data; |
| 797 | |
Ingo Molnar | 9f66a38 | 2008-12-10 12:33:23 +0100 | [diff] [blame] | 798 | switch (counter->hw_event.record_type) { |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 799 | case PERF_RECORD_SIMPLE: |
| 800 | return perf_read_hw(counter, buf, count); |
| 801 | |
| 802 | case PERF_RECORD_IRQ: |
| 803 | case PERF_RECORD_GROUP: |
| 804 | return perf_read_irq_data(counter, buf, count, |
| 805 | file->f_flags & O_NONBLOCK); |
| 806 | } |
| 807 | return -EINVAL; |
| 808 | } |
| 809 | |
| 810 | static unsigned int perf_poll(struct file *file, poll_table *wait) |
| 811 | { |
| 812 | struct perf_counter *counter = file->private_data; |
| 813 | unsigned int events = 0; |
| 814 | unsigned long flags; |
| 815 | |
| 816 | poll_wait(file, &counter->waitq, wait); |
| 817 | |
| 818 | spin_lock_irqsave(&counter->waitq.lock, flags); |
| 819 | if (counter->usrdata->len || counter->irqdata->len) |
| 820 | events |= POLLIN; |
| 821 | spin_unlock_irqrestore(&counter->waitq.lock, flags); |
| 822 | |
| 823 | return events; |
| 824 | } |
| 825 | |
| 826 | static const struct file_operations perf_fops = { |
| 827 | .release = perf_release, |
| 828 | .read = perf_read, |
| 829 | .poll = perf_poll, |
| 830 | }; |
| 831 | |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 832 | static void cpu_clock_perf_counter_enable(struct perf_counter *counter) |
| 833 | { |
| 834 | } |
| 835 | |
| 836 | static void cpu_clock_perf_counter_disable(struct perf_counter *counter) |
| 837 | { |
| 838 | } |
| 839 | |
| 840 | static void cpu_clock_perf_counter_read(struct perf_counter *counter) |
| 841 | { |
| 842 | int cpu = raw_smp_processor_id(); |
| 843 | |
Ingo Molnar | ee06094 | 2008-12-13 09:00:03 +0100 | [diff] [blame] | 844 | atomic64_set(&counter->count, cpu_clock(cpu)); |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 845 | } |
| 846 | |
| 847 | static const struct hw_perf_counter_ops perf_ops_cpu_clock = { |
| 848 | .hw_perf_counter_enable = cpu_clock_perf_counter_enable, |
| 849 | .hw_perf_counter_disable = cpu_clock_perf_counter_disable, |
| 850 | .hw_perf_counter_read = cpu_clock_perf_counter_read, |
| 851 | }; |
| 852 | |
Ingo Molnar | 8cb391e | 2008-12-14 12:22:31 +0100 | [diff] [blame] | 853 | static void task_clock_perf_counter_update(struct perf_counter *counter) |
Ingo Molnar | bae43c9 | 2008-12-11 14:03:20 +0100 | [diff] [blame] | 854 | { |
Ingo Molnar | 8cb391e | 2008-12-14 12:22:31 +0100 | [diff] [blame] | 855 | u64 prev, now; |
| 856 | s64 delta; |
Ingo Molnar | bae43c9 | 2008-12-11 14:03:20 +0100 | [diff] [blame] | 857 | |
Ingo Molnar | 8cb391e | 2008-12-14 12:22:31 +0100 | [diff] [blame] | 858 | prev = atomic64_read(&counter->hw.prev_count); |
| 859 | now = current->se.sum_exec_runtime; |
| 860 | |
| 861 | atomic64_set(&counter->hw.prev_count, now); |
| 862 | |
| 863 | delta = now - prev; |
| 864 | if (WARN_ON_ONCE(delta < 0)) |
| 865 | delta = 0; |
| 866 | |
| 867 | atomic64_add(delta, &counter->count); |
Ingo Molnar | bae43c9 | 2008-12-11 14:03:20 +0100 | [diff] [blame] | 868 | } |
| 869 | |
| 870 | static void task_clock_perf_counter_read(struct perf_counter *counter) |
| 871 | { |
Ingo Molnar | 8cb391e | 2008-12-14 12:22:31 +0100 | [diff] [blame] | 872 | task_clock_perf_counter_update(counter); |
| 873 | } |
| 874 | |
| 875 | static void task_clock_perf_counter_enable(struct perf_counter *counter) |
| 876 | { |
| 877 | atomic64_set(&counter->hw.prev_count, current->se.sum_exec_runtime); |
| 878 | } |
| 879 | |
| 880 | static void task_clock_perf_counter_disable(struct perf_counter *counter) |
| 881 | { |
| 882 | task_clock_perf_counter_update(counter); |
Ingo Molnar | bae43c9 | 2008-12-11 14:03:20 +0100 | [diff] [blame] | 883 | } |
| 884 | |
| 885 | static const struct hw_perf_counter_ops perf_ops_task_clock = { |
| 886 | .hw_perf_counter_enable = task_clock_perf_counter_enable, |
| 887 | .hw_perf_counter_disable = task_clock_perf_counter_disable, |
| 888 | .hw_perf_counter_read = task_clock_perf_counter_read, |
| 889 | }; |
| 890 | |
Ingo Molnar | e06c61a | 2008-12-14 14:44:31 +0100 | [diff] [blame^] | 891 | static u64 get_page_faults(void) |
| 892 | { |
| 893 | struct task_struct *curr = current; |
| 894 | |
| 895 | return curr->maj_flt + curr->min_flt; |
| 896 | } |
| 897 | |
| 898 | static void page_faults_perf_counter_update(struct perf_counter *counter) |
| 899 | { |
| 900 | u64 prev, now; |
| 901 | s64 delta; |
| 902 | |
| 903 | prev = atomic64_read(&counter->hw.prev_count); |
| 904 | now = get_page_faults(); |
| 905 | |
| 906 | atomic64_set(&counter->hw.prev_count, now); |
| 907 | |
| 908 | delta = now - prev; |
| 909 | if (WARN_ON_ONCE(delta < 0)) |
| 910 | delta = 0; |
| 911 | |
| 912 | atomic64_add(delta, &counter->count); |
| 913 | } |
| 914 | |
| 915 | static void page_faults_perf_counter_read(struct perf_counter *counter) |
| 916 | { |
| 917 | page_faults_perf_counter_update(counter); |
| 918 | } |
| 919 | |
| 920 | static void page_faults_perf_counter_enable(struct perf_counter *counter) |
| 921 | { |
| 922 | /* |
| 923 | * page-faults is a per-task value already, |
| 924 | * so we dont have to clear it on switch-in. |
| 925 | */ |
| 926 | } |
| 927 | |
| 928 | static void page_faults_perf_counter_disable(struct perf_counter *counter) |
| 929 | { |
| 930 | page_faults_perf_counter_update(counter); |
| 931 | } |
| 932 | |
| 933 | static const struct hw_perf_counter_ops perf_ops_page_faults = { |
| 934 | .hw_perf_counter_enable = page_faults_perf_counter_enable, |
| 935 | .hw_perf_counter_disable = page_faults_perf_counter_disable, |
| 936 | .hw_perf_counter_read = page_faults_perf_counter_read, |
| 937 | }; |
| 938 | |
Ingo Molnar | 5d6a27d | 2008-12-14 12:28:33 +0100 | [diff] [blame] | 939 | static u64 get_context_switches(void) |
| 940 | { |
| 941 | struct task_struct *curr = current; |
| 942 | |
| 943 | return curr->nvcsw + curr->nivcsw; |
| 944 | } |
| 945 | |
| 946 | static void context_switches_perf_counter_update(struct perf_counter *counter) |
| 947 | { |
| 948 | u64 prev, now; |
| 949 | s64 delta; |
| 950 | |
| 951 | prev = atomic64_read(&counter->hw.prev_count); |
| 952 | now = get_context_switches(); |
| 953 | |
| 954 | atomic64_set(&counter->hw.prev_count, now); |
| 955 | |
| 956 | delta = now - prev; |
| 957 | if (WARN_ON_ONCE(delta < 0)) |
| 958 | delta = 0; |
| 959 | |
| 960 | atomic64_add(delta, &counter->count); |
| 961 | } |
| 962 | |
| 963 | static void context_switches_perf_counter_read(struct perf_counter *counter) |
| 964 | { |
| 965 | context_switches_perf_counter_update(counter); |
| 966 | } |
| 967 | |
| 968 | static void context_switches_perf_counter_enable(struct perf_counter *counter) |
| 969 | { |
| 970 | /* |
| 971 | * ->nvcsw + curr->nivcsw is a per-task value already, |
| 972 | * so we dont have to clear it on switch-in. |
| 973 | */ |
| 974 | } |
| 975 | |
| 976 | static void context_switches_perf_counter_disable(struct perf_counter *counter) |
| 977 | { |
| 978 | context_switches_perf_counter_update(counter); |
| 979 | } |
| 980 | |
| 981 | static const struct hw_perf_counter_ops perf_ops_context_switches = { |
| 982 | .hw_perf_counter_enable = context_switches_perf_counter_enable, |
| 983 | .hw_perf_counter_disable = context_switches_perf_counter_disable, |
| 984 | .hw_perf_counter_read = context_switches_perf_counter_read, |
| 985 | }; |
| 986 | |
Ingo Molnar | 6c594c2 | 2008-12-14 12:34:15 +0100 | [diff] [blame] | 987 | static inline u64 get_cpu_migrations(void) |
| 988 | { |
| 989 | return current->se.nr_migrations; |
| 990 | } |
| 991 | |
| 992 | static void cpu_migrations_perf_counter_update(struct perf_counter *counter) |
| 993 | { |
| 994 | u64 prev, now; |
| 995 | s64 delta; |
| 996 | |
| 997 | prev = atomic64_read(&counter->hw.prev_count); |
| 998 | now = get_cpu_migrations(); |
| 999 | |
| 1000 | atomic64_set(&counter->hw.prev_count, now); |
| 1001 | |
| 1002 | delta = now - prev; |
| 1003 | if (WARN_ON_ONCE(delta < 0)) |
| 1004 | delta = 0; |
| 1005 | |
| 1006 | atomic64_add(delta, &counter->count); |
| 1007 | } |
| 1008 | |
| 1009 | static void cpu_migrations_perf_counter_read(struct perf_counter *counter) |
| 1010 | { |
| 1011 | cpu_migrations_perf_counter_update(counter); |
| 1012 | } |
| 1013 | |
| 1014 | static void cpu_migrations_perf_counter_enable(struct perf_counter *counter) |
| 1015 | { |
| 1016 | /* |
| 1017 | * se.nr_migrations is a per-task value already, |
| 1018 | * so we dont have to clear it on switch-in. |
| 1019 | */ |
| 1020 | } |
| 1021 | |
| 1022 | static void cpu_migrations_perf_counter_disable(struct perf_counter *counter) |
| 1023 | { |
| 1024 | cpu_migrations_perf_counter_update(counter); |
| 1025 | } |
| 1026 | |
| 1027 | static const struct hw_perf_counter_ops perf_ops_cpu_migrations = { |
| 1028 | .hw_perf_counter_enable = cpu_migrations_perf_counter_enable, |
| 1029 | .hw_perf_counter_disable = cpu_migrations_perf_counter_disable, |
| 1030 | .hw_perf_counter_read = cpu_migrations_perf_counter_read, |
| 1031 | }; |
| 1032 | |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1033 | static const struct hw_perf_counter_ops * |
| 1034 | sw_perf_counter_init(struct perf_counter *counter) |
| 1035 | { |
| 1036 | const struct hw_perf_counter_ops *hw_ops = NULL; |
| 1037 | |
| 1038 | switch (counter->hw_event.type) { |
| 1039 | case PERF_COUNT_CPU_CLOCK: |
| 1040 | hw_ops = &perf_ops_cpu_clock; |
| 1041 | break; |
Ingo Molnar | bae43c9 | 2008-12-11 14:03:20 +0100 | [diff] [blame] | 1042 | case PERF_COUNT_TASK_CLOCK: |
| 1043 | hw_ops = &perf_ops_task_clock; |
| 1044 | break; |
Ingo Molnar | e06c61a | 2008-12-14 14:44:31 +0100 | [diff] [blame^] | 1045 | case PERF_COUNT_PAGE_FAULTS: |
| 1046 | hw_ops = &perf_ops_page_faults; |
| 1047 | break; |
Ingo Molnar | 5d6a27d | 2008-12-14 12:28:33 +0100 | [diff] [blame] | 1048 | case PERF_COUNT_CONTEXT_SWITCHES: |
| 1049 | hw_ops = &perf_ops_context_switches; |
| 1050 | break; |
Ingo Molnar | 6c594c2 | 2008-12-14 12:34:15 +0100 | [diff] [blame] | 1051 | case PERF_COUNT_CPU_MIGRATIONS: |
| 1052 | hw_ops = &perf_ops_cpu_migrations; |
| 1053 | break; |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1054 | default: |
| 1055 | break; |
| 1056 | } |
| 1057 | return hw_ops; |
| 1058 | } |
| 1059 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1060 | /* |
| 1061 | * Allocate and initialize a counter structure |
| 1062 | */ |
| 1063 | static struct perf_counter * |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1064 | perf_counter_alloc(struct perf_counter_hw_event *hw_event, |
| 1065 | int cpu, |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1066 | struct perf_counter *group_leader, |
| 1067 | gfp_t gfpflags) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1068 | { |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1069 | const struct hw_perf_counter_ops *hw_ops; |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 1070 | struct perf_counter *counter; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1071 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1072 | counter = kzalloc(sizeof(*counter), gfpflags); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1073 | if (!counter) |
| 1074 | return NULL; |
| 1075 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1076 | /* |
| 1077 | * Single counters are their own group leaders, with an |
| 1078 | * empty sibling list: |
| 1079 | */ |
| 1080 | if (!group_leader) |
| 1081 | group_leader = counter; |
| 1082 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1083 | mutex_init(&counter->mutex); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1084 | INIT_LIST_HEAD(&counter->list_entry); |
| 1085 | INIT_LIST_HEAD(&counter->sibling_list); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1086 | init_waitqueue_head(&counter->waitq); |
| 1087 | |
Ingo Molnar | 9f66a38 | 2008-12-10 12:33:23 +0100 | [diff] [blame] | 1088 | counter->irqdata = &counter->data[0]; |
| 1089 | counter->usrdata = &counter->data[1]; |
| 1090 | counter->cpu = cpu; |
| 1091 | counter->hw_event = *hw_event; |
| 1092 | counter->wakeup_pending = 0; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1093 | counter->group_leader = group_leader; |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 1094 | counter->hw_ops = NULL; |
| 1095 | |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1096 | hw_ops = NULL; |
| 1097 | if (!hw_event->raw && hw_event->type < 0) |
| 1098 | hw_ops = sw_perf_counter_init(counter); |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1099 | if (!hw_ops) |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1100 | hw_ops = hw_perf_counter_init(counter); |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1101 | |
Ingo Molnar | 621a01e | 2008-12-11 12:46:46 +0100 | [diff] [blame] | 1102 | if (!hw_ops) { |
| 1103 | kfree(counter); |
| 1104 | return NULL; |
| 1105 | } |
| 1106 | counter->hw_ops = hw_ops; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1107 | |
| 1108 | return counter; |
| 1109 | } |
| 1110 | |
| 1111 | /** |
Ingo Molnar | 9f66a38 | 2008-12-10 12:33:23 +0100 | [diff] [blame] | 1112 | * sys_perf_task_open - open a performance counter, associate it to a task/cpu |
| 1113 | * |
| 1114 | * @hw_event_uptr: event type attributes for monitoring/sampling |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1115 | * @pid: target pid |
Ingo Molnar | 9f66a38 | 2008-12-10 12:33:23 +0100 | [diff] [blame] | 1116 | * @cpu: target cpu |
| 1117 | * @group_fd: group leader counter fd |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1118 | */ |
Ingo Molnar | 1d1c7dd | 2008-12-11 14:59:31 +0100 | [diff] [blame] | 1119 | asmlinkage int |
| 1120 | sys_perf_counter_open(struct perf_counter_hw_event *hw_event_uptr __user, |
| 1121 | pid_t pid, int cpu, int group_fd) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1122 | { |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1123 | struct perf_counter *counter, *group_leader; |
Ingo Molnar | 9f66a38 | 2008-12-10 12:33:23 +0100 | [diff] [blame] | 1124 | struct perf_counter_hw_event hw_event; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1125 | struct perf_counter_context *ctx; |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1126 | struct file *counter_file = NULL; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1127 | struct file *group_file = NULL; |
| 1128 | int fput_needed = 0; |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1129 | int fput_needed2 = 0; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1130 | int ret; |
| 1131 | |
Ingo Molnar | 9f66a38 | 2008-12-10 12:33:23 +0100 | [diff] [blame] | 1132 | if (copy_from_user(&hw_event, hw_event_uptr, sizeof(hw_event)) != 0) |
Thomas Gleixner | eab656a | 2008-12-08 19:26:59 +0100 | [diff] [blame] | 1133 | return -EFAULT; |
| 1134 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1135 | /* |
Ingo Molnar | ccff286 | 2008-12-11 11:26:29 +0100 | [diff] [blame] | 1136 | * Get the target context (task or percpu): |
| 1137 | */ |
| 1138 | ctx = find_get_context(pid, cpu); |
| 1139 | if (IS_ERR(ctx)) |
| 1140 | return PTR_ERR(ctx); |
| 1141 | |
| 1142 | /* |
| 1143 | * Look up the group leader (we will attach this counter to it): |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1144 | */ |
| 1145 | group_leader = NULL; |
| 1146 | if (group_fd != -1) { |
| 1147 | ret = -EINVAL; |
| 1148 | group_file = fget_light(group_fd, &fput_needed); |
| 1149 | if (!group_file) |
Ingo Molnar | ccff286 | 2008-12-11 11:26:29 +0100 | [diff] [blame] | 1150 | goto err_put_context; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1151 | if (group_file->f_op != &perf_fops) |
Ingo Molnar | ccff286 | 2008-12-11 11:26:29 +0100 | [diff] [blame] | 1152 | goto err_put_context; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1153 | |
| 1154 | group_leader = group_file->private_data; |
| 1155 | /* |
Ingo Molnar | ccff286 | 2008-12-11 11:26:29 +0100 | [diff] [blame] | 1156 | * Do not allow a recursive hierarchy (this new sibling |
| 1157 | * becoming part of another group-sibling): |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1158 | */ |
Ingo Molnar | ccff286 | 2008-12-11 11:26:29 +0100 | [diff] [blame] | 1159 | if (group_leader->group_leader != group_leader) |
| 1160 | goto err_put_context; |
| 1161 | /* |
| 1162 | * Do not allow to attach to a group in a different |
| 1163 | * task or CPU context: |
| 1164 | */ |
| 1165 | if (group_leader->ctx != ctx) |
| 1166 | goto err_put_context; |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1167 | } |
| 1168 | |
Ingo Molnar | 5c92d12 | 2008-12-11 13:21:10 +0100 | [diff] [blame] | 1169 | ret = -EINVAL; |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1170 | counter = perf_counter_alloc(&hw_event, cpu, group_leader, GFP_KERNEL); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1171 | if (!counter) |
| 1172 | goto err_put_context; |
| 1173 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1174 | ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0); |
| 1175 | if (ret < 0) |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1176 | goto err_free_put_context; |
| 1177 | |
| 1178 | counter_file = fget_light(ret, &fput_needed2); |
| 1179 | if (!counter_file) |
| 1180 | goto err_free_put_context; |
| 1181 | |
| 1182 | counter->filp = counter_file; |
| 1183 | perf_install_in_context(ctx, counter, cpu); |
| 1184 | |
| 1185 | fput_light(counter_file, fput_needed2); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1186 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1187 | out_fput: |
| 1188 | fput_light(group_file, fput_needed); |
| 1189 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1190 | return ret; |
| 1191 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1192 | err_free_put_context: |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1193 | kfree(counter); |
| 1194 | |
| 1195 | err_put_context: |
| 1196 | put_context(ctx); |
| 1197 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1198 | goto out_fput; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1199 | } |
| 1200 | |
Ingo Molnar | 9b51f66 | 2008-12-12 13:49:45 +0100 | [diff] [blame] | 1201 | /* |
| 1202 | * Initialize the perf_counter context in a task_struct: |
| 1203 | */ |
| 1204 | static void |
| 1205 | __perf_counter_init_context(struct perf_counter_context *ctx, |
| 1206 | struct task_struct *task) |
| 1207 | { |
| 1208 | memset(ctx, 0, sizeof(*ctx)); |
| 1209 | spin_lock_init(&ctx->lock); |
| 1210 | INIT_LIST_HEAD(&ctx->counter_list); |
| 1211 | ctx->task = task; |
| 1212 | } |
| 1213 | |
| 1214 | /* |
| 1215 | * inherit a counter from parent task to child task: |
| 1216 | */ |
| 1217 | static int |
| 1218 | inherit_counter(struct perf_counter *parent_counter, |
| 1219 | struct task_struct *parent, |
| 1220 | struct perf_counter_context *parent_ctx, |
| 1221 | struct task_struct *child, |
| 1222 | struct perf_counter_context *child_ctx) |
| 1223 | { |
| 1224 | struct perf_counter *child_counter; |
| 1225 | |
| 1226 | child_counter = perf_counter_alloc(&parent_counter->hw_event, |
| 1227 | parent_counter->cpu, NULL, |
| 1228 | GFP_ATOMIC); |
| 1229 | if (!child_counter) |
| 1230 | return -ENOMEM; |
| 1231 | |
| 1232 | /* |
| 1233 | * Link it up in the child's context: |
| 1234 | */ |
| 1235 | child_counter->ctx = child_ctx; |
| 1236 | child_counter->task = child; |
| 1237 | list_add_counter(child_counter, child_ctx); |
| 1238 | child_ctx->nr_counters++; |
| 1239 | |
| 1240 | child_counter->parent = parent_counter; |
| 1241 | parent_counter->nr_inherited++; |
| 1242 | /* |
| 1243 | * inherit into child's child as well: |
| 1244 | */ |
| 1245 | child_counter->hw_event.inherit = 1; |
| 1246 | |
| 1247 | /* |
| 1248 | * Get a reference to the parent filp - we will fput it |
| 1249 | * when the child counter exits. This is safe to do because |
| 1250 | * we are in the parent and we know that the filp still |
| 1251 | * exists and has a nonzero count: |
| 1252 | */ |
| 1253 | atomic_long_inc(&parent_counter->filp->f_count); |
| 1254 | |
| 1255 | return 0; |
| 1256 | } |
| 1257 | |
| 1258 | static void |
| 1259 | __perf_counter_exit_task(struct task_struct *child, |
| 1260 | struct perf_counter *child_counter, |
| 1261 | struct perf_counter_context *child_ctx) |
| 1262 | { |
| 1263 | struct perf_counter *parent_counter; |
| 1264 | u64 parent_val, child_val; |
| 1265 | u64 perf_flags; |
| 1266 | |
| 1267 | /* |
| 1268 | * Disable and unlink this counter. |
| 1269 | * |
| 1270 | * Be careful about zapping the list - IRQ/NMI context |
| 1271 | * could still be processing it: |
| 1272 | */ |
| 1273 | local_irq_disable(); |
| 1274 | perf_flags = hw_perf_save_disable(); |
| 1275 | |
| 1276 | if (child_counter->state == PERF_COUNTER_STATE_ACTIVE) |
| 1277 | child_counter->hw_ops->hw_perf_counter_disable(child_counter); |
| 1278 | list_del_init(&child_counter->list_entry); |
| 1279 | |
| 1280 | hw_perf_restore(perf_flags); |
| 1281 | local_irq_enable(); |
| 1282 | |
| 1283 | parent_counter = child_counter->parent; |
| 1284 | /* |
| 1285 | * It can happen that parent exits first, and has counters |
| 1286 | * that are still around due to the child reference. These |
| 1287 | * counters need to be zapped - but otherwise linger. |
| 1288 | */ |
| 1289 | if (!parent_counter) |
| 1290 | return; |
| 1291 | |
| 1292 | parent_val = atomic64_read(&parent_counter->count); |
| 1293 | child_val = atomic64_read(&child_counter->count); |
| 1294 | |
| 1295 | /* |
| 1296 | * Add back the child's count to the parent's count: |
| 1297 | */ |
| 1298 | atomic64_add(child_val, &parent_counter->count); |
| 1299 | |
| 1300 | fput(parent_counter->filp); |
| 1301 | |
| 1302 | kfree(child_counter); |
| 1303 | } |
| 1304 | |
| 1305 | /* |
| 1306 | * When a child task exist, feed back counter values to parent counters. |
| 1307 | * |
| 1308 | * Note: we are running in child context, but the PID is not hashed |
| 1309 | * anymore so new counters will not be added. |
| 1310 | */ |
| 1311 | void perf_counter_exit_task(struct task_struct *child) |
| 1312 | { |
| 1313 | struct perf_counter *child_counter, *tmp; |
| 1314 | struct perf_counter_context *child_ctx; |
| 1315 | |
| 1316 | child_ctx = &child->perf_counter_ctx; |
| 1317 | |
| 1318 | if (likely(!child_ctx->nr_counters)) |
| 1319 | return; |
| 1320 | |
| 1321 | list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list, |
| 1322 | list_entry) |
| 1323 | __perf_counter_exit_task(child, child_counter, child_ctx); |
| 1324 | } |
| 1325 | |
| 1326 | /* |
| 1327 | * Initialize the perf_counter context in task_struct |
| 1328 | */ |
| 1329 | void perf_counter_init_task(struct task_struct *child) |
| 1330 | { |
| 1331 | struct perf_counter_context *child_ctx, *parent_ctx; |
| 1332 | struct perf_counter *counter, *parent_counter; |
| 1333 | struct task_struct *parent = current; |
| 1334 | unsigned long flags; |
| 1335 | |
| 1336 | child_ctx = &child->perf_counter_ctx; |
| 1337 | parent_ctx = &parent->perf_counter_ctx; |
| 1338 | |
| 1339 | __perf_counter_init_context(child_ctx, child); |
| 1340 | |
| 1341 | /* |
| 1342 | * This is executed from the parent task context, so inherit |
| 1343 | * counters that have been marked for cloning: |
| 1344 | */ |
| 1345 | |
| 1346 | if (likely(!parent_ctx->nr_counters)) |
| 1347 | return; |
| 1348 | |
| 1349 | /* |
| 1350 | * Lock the parent list. No need to lock the child - not PID |
| 1351 | * hashed yet and not running, so nobody can access it. |
| 1352 | */ |
| 1353 | spin_lock_irqsave(&parent_ctx->lock, flags); |
| 1354 | |
| 1355 | /* |
| 1356 | * We dont have to disable NMIs - we are only looking at |
| 1357 | * the list, not manipulating it: |
| 1358 | */ |
| 1359 | list_for_each_entry(counter, &parent_ctx->counter_list, list_entry) { |
| 1360 | if (!counter->hw_event.inherit || counter->group_leader != counter) |
| 1361 | continue; |
| 1362 | |
| 1363 | /* |
| 1364 | * Instead of creating recursive hierarchies of counters, |
| 1365 | * we link inheritd counters back to the original parent, |
| 1366 | * which has a filp for sure, which we use as the reference |
| 1367 | * count: |
| 1368 | */ |
| 1369 | parent_counter = counter; |
| 1370 | if (counter->parent) |
| 1371 | parent_counter = counter->parent; |
| 1372 | |
| 1373 | if (inherit_counter(parent_counter, parent, |
| 1374 | parent_ctx, child, child_ctx)) |
| 1375 | break; |
| 1376 | } |
| 1377 | |
| 1378 | spin_unlock_irqrestore(&parent_ctx->lock, flags); |
| 1379 | } |
| 1380 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1381 | static void __cpuinit perf_counter_init_cpu(int cpu) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1382 | { |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1383 | struct perf_cpu_context *cpuctx; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1384 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1385 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
| 1386 | __perf_counter_init_context(&cpuctx->ctx, NULL); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1387 | |
| 1388 | mutex_lock(&perf_resource_mutex); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1389 | cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu; |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1390 | mutex_unlock(&perf_resource_mutex); |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1391 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1392 | hw_perf_counter_setup(); |
| 1393 | } |
| 1394 | |
| 1395 | #ifdef CONFIG_HOTPLUG_CPU |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1396 | static void __perf_counter_exit_cpu(void *info) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1397 | { |
| 1398 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| 1399 | struct perf_counter_context *ctx = &cpuctx->ctx; |
| 1400 | struct perf_counter *counter, *tmp; |
| 1401 | |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1402 | list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry) |
| 1403 | __perf_counter_remove_from_context(counter); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1404 | |
| 1405 | } |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1406 | static void perf_counter_exit_cpu(int cpu) |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1407 | { |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1408 | smp_call_function_single(cpu, __perf_counter_exit_cpu, NULL, 1); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1409 | } |
| 1410 | #else |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1411 | static inline void perf_counter_exit_cpu(int cpu) { } |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1412 | #endif |
| 1413 | |
| 1414 | static int __cpuinit |
| 1415 | perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) |
| 1416 | { |
| 1417 | unsigned int cpu = (long)hcpu; |
| 1418 | |
| 1419 | switch (action) { |
| 1420 | |
| 1421 | case CPU_UP_PREPARE: |
| 1422 | case CPU_UP_PREPARE_FROZEN: |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1423 | perf_counter_init_cpu(cpu); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1424 | break; |
| 1425 | |
| 1426 | case CPU_DOWN_PREPARE: |
| 1427 | case CPU_DOWN_PREPARE_FROZEN: |
Ingo Molnar | 04289bb | 2008-12-11 08:38:42 +0100 | [diff] [blame] | 1428 | perf_counter_exit_cpu(cpu); |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1429 | break; |
| 1430 | |
| 1431 | default: |
| 1432 | break; |
| 1433 | } |
| 1434 | |
| 1435 | return NOTIFY_OK; |
| 1436 | } |
| 1437 | |
| 1438 | static struct notifier_block __cpuinitdata perf_cpu_nb = { |
| 1439 | .notifier_call = perf_cpu_notify, |
| 1440 | }; |
| 1441 | |
| 1442 | static int __init perf_counter_init(void) |
| 1443 | { |
| 1444 | perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE, |
| 1445 | (void *)(long)smp_processor_id()); |
| 1446 | register_cpu_notifier(&perf_cpu_nb); |
| 1447 | |
| 1448 | return 0; |
| 1449 | } |
| 1450 | early_initcall(perf_counter_init); |
| 1451 | |
| 1452 | static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf) |
| 1453 | { |
| 1454 | return sprintf(buf, "%d\n", perf_reserved_percpu); |
| 1455 | } |
| 1456 | |
| 1457 | static ssize_t |
| 1458 | perf_set_reserve_percpu(struct sysdev_class *class, |
| 1459 | const char *buf, |
| 1460 | size_t count) |
| 1461 | { |
| 1462 | struct perf_cpu_context *cpuctx; |
| 1463 | unsigned long val; |
| 1464 | int err, cpu, mpt; |
| 1465 | |
| 1466 | err = strict_strtoul(buf, 10, &val); |
| 1467 | if (err) |
| 1468 | return err; |
| 1469 | if (val > perf_max_counters) |
| 1470 | return -EINVAL; |
| 1471 | |
| 1472 | mutex_lock(&perf_resource_mutex); |
| 1473 | perf_reserved_percpu = val; |
| 1474 | for_each_online_cpu(cpu) { |
| 1475 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
| 1476 | spin_lock_irq(&cpuctx->ctx.lock); |
| 1477 | mpt = min(perf_max_counters - cpuctx->ctx.nr_counters, |
| 1478 | perf_max_counters - perf_reserved_percpu); |
| 1479 | cpuctx->max_pertask = mpt; |
| 1480 | spin_unlock_irq(&cpuctx->ctx.lock); |
| 1481 | } |
| 1482 | mutex_unlock(&perf_resource_mutex); |
| 1483 | |
| 1484 | return count; |
| 1485 | } |
| 1486 | |
| 1487 | static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf) |
| 1488 | { |
| 1489 | return sprintf(buf, "%d\n", perf_overcommit); |
| 1490 | } |
| 1491 | |
| 1492 | static ssize_t |
| 1493 | perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count) |
| 1494 | { |
| 1495 | unsigned long val; |
| 1496 | int err; |
| 1497 | |
| 1498 | err = strict_strtoul(buf, 10, &val); |
| 1499 | if (err) |
| 1500 | return err; |
| 1501 | if (val > 1) |
| 1502 | return -EINVAL; |
| 1503 | |
| 1504 | mutex_lock(&perf_resource_mutex); |
| 1505 | perf_overcommit = val; |
| 1506 | mutex_unlock(&perf_resource_mutex); |
| 1507 | |
| 1508 | return count; |
| 1509 | } |
| 1510 | |
| 1511 | static SYSDEV_CLASS_ATTR( |
| 1512 | reserve_percpu, |
| 1513 | 0644, |
| 1514 | perf_show_reserve_percpu, |
| 1515 | perf_set_reserve_percpu |
| 1516 | ); |
| 1517 | |
| 1518 | static SYSDEV_CLASS_ATTR( |
| 1519 | overcommit, |
| 1520 | 0644, |
| 1521 | perf_show_overcommit, |
| 1522 | perf_set_overcommit |
| 1523 | ); |
| 1524 | |
| 1525 | static struct attribute *perfclass_attrs[] = { |
| 1526 | &attr_reserve_percpu.attr, |
| 1527 | &attr_overcommit.attr, |
| 1528 | NULL |
| 1529 | }; |
| 1530 | |
| 1531 | static struct attribute_group perfclass_attr_group = { |
| 1532 | .attrs = perfclass_attrs, |
| 1533 | .name = "perf_counters", |
| 1534 | }; |
| 1535 | |
| 1536 | static int __init perf_counter_sysfs_init(void) |
| 1537 | { |
| 1538 | return sysfs_create_group(&cpu_sysdev_class.kset.kobj, |
| 1539 | &perfclass_attr_group); |
| 1540 | } |
| 1541 | device_initcall(perf_counter_sysfs_init); |
| 1542 | |