| /* |
| * Performance counter core code |
| * |
| * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de> |
| * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar |
| * |
| * For licencing details see kernel-base/COPYING |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/cpu.h> |
| #include <linux/smp.h> |
| #include <linux/file.h> |
| #include <linux/poll.h> |
| #include <linux/sysfs.h> |
| #include <linux/ptrace.h> |
| #include <linux/percpu.h> |
| #include <linux/uaccess.h> |
| #include <linux/syscalls.h> |
| #include <linux/anon_inodes.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/perf_counter.h> |
| |
| /* |
| * Each CPU has a list of per CPU counters: |
| */ |
| DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context); |
| |
| int perf_max_counters __read_mostly = 1; |
| static int perf_reserved_percpu __read_mostly; |
| static int perf_overcommit __read_mostly = 1; |
| |
| /* |
| * Mutex for (sysadmin-configurable) counter reservations: |
| */ |
| static DEFINE_MUTEX(perf_resource_mutex); |
| |
| /* |
| * Architecture provided APIs - weak aliases: |
| */ |
| extern __weak const struct hw_perf_counter_ops * |
| hw_perf_counter_init(struct perf_counter *counter) |
| { |
| return ERR_PTR(-EINVAL); |
| } |
| |
| u64 __weak hw_perf_save_disable(void) { return 0; } |
| void __weak hw_perf_restore(u64 ctrl) { } |
| void __weak hw_perf_counter_setup(void) { } |
| |
| static void |
| list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx) |
| { |
| struct perf_counter *group_leader = counter->group_leader; |
| |
| /* |
| * Depending on whether it is a standalone or sibling counter, |
| * add it straight to the context's counter list, or to the group |
| * leader's sibling list: |
| */ |
| if (counter->group_leader == counter) |
| list_add_tail(&counter->list_entry, &ctx->counter_list); |
| else |
| list_add_tail(&counter->list_entry, &group_leader->sibling_list); |
| } |
| |
| static void |
| list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx) |
| { |
| struct perf_counter *sibling, *tmp; |
| |
| list_del_init(&counter->list_entry); |
| |
| /* |
| * If this was a group counter with sibling counters then |
| * upgrade the siblings to singleton counters by adding them |
| * to the context list directly: |
| */ |
| list_for_each_entry_safe(sibling, tmp, |
| &counter->sibling_list, list_entry) { |
| |
| list_del_init(&sibling->list_entry); |
| list_add_tail(&sibling->list_entry, &ctx->counter_list); |
| sibling->group_leader = sibling; |
| } |
| } |
| |
| /* |
| * Cross CPU call to remove a performance counter |
| * |
| * We disable the counter on the hardware level first. After that we |
| * remove it from the context list. |
| */ |
| static void __perf_counter_remove_from_context(void *info) |
| { |
| struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| struct perf_counter *counter = info; |
| struct perf_counter_context *ctx = counter->ctx; |
| unsigned long flags; |
| u64 perf_flags; |
| |
| /* |
| * If this is a task context, we need to check whether it is |
| * the current task context of this cpu. If not it has been |
| * scheduled out before the smp call arrived. |
| */ |
| if (ctx->task && cpuctx->task_ctx != ctx) |
| return; |
| |
| curr_rq_lock_irq_save(&flags); |
| spin_lock(&ctx->lock); |
| |
| if (counter->state == PERF_COUNTER_STATE_ACTIVE) { |
| counter->state = PERF_COUNTER_STATE_INACTIVE; |
| counter->hw_ops->disable(counter); |
| ctx->nr_active--; |
| cpuctx->active_oncpu--; |
| counter->task = NULL; |
| counter->oncpu = -1; |
| } |
| ctx->nr_counters--; |
| |
| /* |
| * Protect the list operation against NMI by disabling the |
| * counters on a global level. NOP for non NMI based counters. |
| */ |
| perf_flags = hw_perf_save_disable(); |
| list_del_counter(counter, ctx); |
| hw_perf_restore(perf_flags); |
| |
| if (!ctx->task) { |
| /* |
| * Allow more per task counters with respect to the |
| * reservation: |
| */ |
| cpuctx->max_pertask = |
| min(perf_max_counters - ctx->nr_counters, |
| perf_max_counters - perf_reserved_percpu); |
| } |
| |
| spin_unlock(&ctx->lock); |
| curr_rq_unlock_irq_restore(&flags); |
| } |
| |
| |
| /* |
| * Remove the counter from a task's (or a CPU's) list of counters. |
| * |
| * Must be called with counter->mutex held. |
| * |
| * CPU counters are removed with a smp call. For task counters we only |
| * call when the task is on a CPU. |
| */ |
| static void perf_counter_remove_from_context(struct perf_counter *counter) |
| { |
| struct perf_counter_context *ctx = counter->ctx; |
| struct task_struct *task = ctx->task; |
| |
| if (!task) { |
| /* |
| * Per cpu counters are removed via an smp call and |
| * the removal is always sucessful. |
| */ |
| smp_call_function_single(counter->cpu, |
| __perf_counter_remove_from_context, |
| counter, 1); |
| return; |
| } |
| |
| retry: |
| task_oncpu_function_call(task, __perf_counter_remove_from_context, |
| counter); |
| |
| spin_lock_irq(&ctx->lock); |
| /* |
| * If the context is active we need to retry the smp call. |
| */ |
| if (ctx->nr_active && !list_empty(&counter->list_entry)) { |
| spin_unlock_irq(&ctx->lock); |
| goto retry; |
| } |
| |
| /* |
| * The lock prevents that this context is scheduled in so we |
| * can remove the counter safely, if the call above did not |
| * succeed. |
| */ |
| if (!list_empty(&counter->list_entry)) { |
| ctx->nr_counters--; |
| list_del_counter(counter, ctx); |
| counter->task = NULL; |
| } |
| spin_unlock_irq(&ctx->lock); |
| } |
| |
| static int |
| counter_sched_in(struct perf_counter *counter, |
| struct perf_cpu_context *cpuctx, |
| struct perf_counter_context *ctx, |
| int cpu) |
| { |
| if (counter->state == PERF_COUNTER_STATE_OFF) |
| return 0; |
| |
| counter->state = PERF_COUNTER_STATE_ACTIVE; |
| counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */ |
| /* |
| * The new state must be visible before we turn it on in the hardware: |
| */ |
| smp_wmb(); |
| |
| if (counter->hw_ops->enable(counter)) { |
| counter->state = PERF_COUNTER_STATE_INACTIVE; |
| counter->oncpu = -1; |
| return -EAGAIN; |
| } |
| |
| cpuctx->active_oncpu++; |
| ctx->nr_active++; |
| |
| return 0; |
| } |
| |
| /* |
| * Cross CPU call to install and enable a performance counter |
| */ |
| static void __perf_install_in_context(void *info) |
| { |
| struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| struct perf_counter *counter = info; |
| struct perf_counter_context *ctx = counter->ctx; |
| int cpu = smp_processor_id(); |
| unsigned long flags; |
| u64 perf_flags; |
| |
| /* |
| * If this is a task context, we need to check whether it is |
| * the current task context of this cpu. If not it has been |
| * scheduled out before the smp call arrived. |
| */ |
| if (ctx->task && cpuctx->task_ctx != ctx) |
| return; |
| |
| curr_rq_lock_irq_save(&flags); |
| spin_lock(&ctx->lock); |
| |
| /* |
| * Protect the list operation against NMI by disabling the |
| * counters on a global level. NOP for non NMI based counters. |
| */ |
| perf_flags = hw_perf_save_disable(); |
| |
| list_add_counter(counter, ctx); |
| ctx->nr_counters++; |
| |
| counter_sched_in(counter, cpuctx, ctx, cpu); |
| |
| if (!ctx->task && cpuctx->max_pertask) |
| cpuctx->max_pertask--; |
| |
| hw_perf_restore(perf_flags); |
| |
| spin_unlock(&ctx->lock); |
| curr_rq_unlock_irq_restore(&flags); |
| } |
| |
| /* |
| * Attach a performance counter to a context |
| * |
| * First we add the counter to the list with the hardware enable bit |
| * in counter->hw_config cleared. |
| * |
| * If the counter is attached to a task which is on a CPU we use a smp |
| * call to enable it in the task context. The task might have been |
| * scheduled away, but we check this in the smp call again. |
| */ |
| static void |
| perf_install_in_context(struct perf_counter_context *ctx, |
| struct perf_counter *counter, |
| int cpu) |
| { |
| struct task_struct *task = ctx->task; |
| |
| counter->ctx = ctx; |
| if (!task) { |
| /* |
| * Per cpu counters are installed via an smp call and |
| * the install is always sucessful. |
| */ |
| smp_call_function_single(cpu, __perf_install_in_context, |
| counter, 1); |
| return; |
| } |
| |
| counter->task = task; |
| retry: |
| task_oncpu_function_call(task, __perf_install_in_context, |
| counter); |
| |
| spin_lock_irq(&ctx->lock); |
| /* |
| * we need to retry the smp call. |
| */ |
| if (ctx->nr_active && list_empty(&counter->list_entry)) { |
| spin_unlock_irq(&ctx->lock); |
| goto retry; |
| } |
| |
| /* |
| * The lock prevents that this context is scheduled in so we |
| * can add the counter safely, if it the call above did not |
| * succeed. |
| */ |
| if (list_empty(&counter->list_entry)) { |
| list_add_counter(counter, ctx); |
| ctx->nr_counters++; |
| } |
| spin_unlock_irq(&ctx->lock); |
| } |
| |
| static void |
| counter_sched_out(struct perf_counter *counter, |
| struct perf_cpu_context *cpuctx, |
| struct perf_counter_context *ctx) |
| { |
| if (counter->state != PERF_COUNTER_STATE_ACTIVE) |
| return; |
| |
| counter->state = PERF_COUNTER_STATE_INACTIVE; |
| counter->hw_ops->disable(counter); |
| counter->oncpu = -1; |
| |
| cpuctx->active_oncpu--; |
| ctx->nr_active--; |
| } |
| |
| static void |
| group_sched_out(struct perf_counter *group_counter, |
| struct perf_cpu_context *cpuctx, |
| struct perf_counter_context *ctx) |
| { |
| struct perf_counter *counter; |
| |
| counter_sched_out(group_counter, cpuctx, ctx); |
| |
| /* |
| * Schedule out siblings (if any): |
| */ |
| list_for_each_entry(counter, &group_counter->sibling_list, list_entry) |
| counter_sched_out(counter, cpuctx, ctx); |
| } |
| |
| void __perf_counter_sched_out(struct perf_counter_context *ctx, |
| struct perf_cpu_context *cpuctx) |
| { |
| struct perf_counter *counter; |
| |
| if (likely(!ctx->nr_counters)) |
| return; |
| |
| spin_lock(&ctx->lock); |
| if (ctx->nr_active) { |
| list_for_each_entry(counter, &ctx->counter_list, list_entry) |
| group_sched_out(counter, cpuctx, ctx); |
| } |
| spin_unlock(&ctx->lock); |
| } |
| |
| /* |
| * Called from scheduler to remove the counters of the current task, |
| * with interrupts disabled. |
| * |
| * We stop each counter and update the counter value in counter->count. |
| * |
| * This does not protect us against NMI, but disable() |
| * sets the disabled bit in the control field of counter _before_ |
| * accessing the counter control register. If a NMI hits, then it will |
| * not restart the counter. |
| */ |
| void perf_counter_task_sched_out(struct task_struct *task, int cpu) |
| { |
| struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); |
| struct perf_counter_context *ctx = &task->perf_counter_ctx; |
| |
| if (likely(!cpuctx->task_ctx)) |
| return; |
| |
| __perf_counter_sched_out(ctx, cpuctx); |
| |
| cpuctx->task_ctx = NULL; |
| } |
| |
| static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx) |
| { |
| __perf_counter_sched_out(&cpuctx->ctx, cpuctx); |
| } |
| |
| static int |
| group_sched_in(struct perf_counter *group_counter, |
| struct perf_cpu_context *cpuctx, |
| struct perf_counter_context *ctx, |
| int cpu) |
| { |
| struct perf_counter *counter, *partial_group; |
| int ret = 0; |
| |
| if (counter_sched_in(group_counter, cpuctx, ctx, cpu)) |
| return -EAGAIN; |
| |
| /* |
| * Schedule in siblings as one group (if any): |
| */ |
| list_for_each_entry(counter, &group_counter->sibling_list, list_entry) { |
| if (counter_sched_in(counter, cpuctx, ctx, cpu)) { |
| partial_group = counter; |
| goto group_error; |
| } |
| ret = -EAGAIN; |
| } |
| |
| return ret; |
| |
| group_error: |
| /* |
| * Groups can be scheduled in as one unit only, so undo any |
| * partial group before returning: |
| */ |
| list_for_each_entry(counter, &group_counter->sibling_list, list_entry) { |
| if (counter == partial_group) |
| break; |
| counter_sched_out(counter, cpuctx, ctx); |
| } |
| counter_sched_out(group_counter, cpuctx, ctx); |
| |
| return -EAGAIN; |
| } |
| |
| static void |
| __perf_counter_sched_in(struct perf_counter_context *ctx, |
| struct perf_cpu_context *cpuctx, int cpu) |
| { |
| struct perf_counter *counter; |
| |
| if (likely(!ctx->nr_counters)) |
| return; |
| |
| spin_lock(&ctx->lock); |
| list_for_each_entry(counter, &ctx->counter_list, list_entry) { |
| /* |
| * Listen to the 'cpu' scheduling filter constraint |
| * of counters: |
| */ |
| if (counter->cpu != -1 && counter->cpu != cpu) |
| continue; |
| |
| /* |
| * If we scheduled in a group atomically and |
| * exclusively, break out: |
| */ |
| if (group_sched_in(counter, cpuctx, ctx, cpu)) |
| break; |
| } |
| spin_unlock(&ctx->lock); |
| } |
| |
| /* |
| * Called from scheduler to add the counters of the current task |
| * with interrupts disabled. |
| * |
| * We restore the counter value and then enable it. |
| * |
| * This does not protect us against NMI, but enable() |
| * sets the enabled bit in the control field of counter _before_ |
| * accessing the counter control register. If a NMI hits, then it will |
| * keep the counter running. |
| */ |
| void perf_counter_task_sched_in(struct task_struct *task, int cpu) |
| { |
| struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); |
| struct perf_counter_context *ctx = &task->perf_counter_ctx; |
| |
| __perf_counter_sched_in(ctx, cpuctx, cpu); |
| cpuctx->task_ctx = ctx; |
| } |
| |
| static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu) |
| { |
| struct perf_counter_context *ctx = &cpuctx->ctx; |
| |
| __perf_counter_sched_in(ctx, cpuctx, cpu); |
| } |
| |
| int perf_counter_task_disable(void) |
| { |
| struct task_struct *curr = current; |
| struct perf_counter_context *ctx = &curr->perf_counter_ctx; |
| struct perf_counter *counter; |
| unsigned long flags; |
| u64 perf_flags; |
| int cpu; |
| |
| if (likely(!ctx->nr_counters)) |
| return 0; |
| |
| curr_rq_lock_irq_save(&flags); |
| cpu = smp_processor_id(); |
| |
| /* force the update of the task clock: */ |
| __task_delta_exec(curr, 1); |
| |
| perf_counter_task_sched_out(curr, cpu); |
| |
| spin_lock(&ctx->lock); |
| |
| /* |
| * Disable all the counters: |
| */ |
| perf_flags = hw_perf_save_disable(); |
| |
| list_for_each_entry(counter, &ctx->counter_list, list_entry) |
| counter->state = PERF_COUNTER_STATE_OFF; |
| |
| hw_perf_restore(perf_flags); |
| |
| spin_unlock(&ctx->lock); |
| |
| curr_rq_unlock_irq_restore(&flags); |
| |
| return 0; |
| } |
| |
| int perf_counter_task_enable(void) |
| { |
| struct task_struct *curr = current; |
| struct perf_counter_context *ctx = &curr->perf_counter_ctx; |
| struct perf_counter *counter; |
| unsigned long flags; |
| u64 perf_flags; |
| int cpu; |
| |
| if (likely(!ctx->nr_counters)) |
| return 0; |
| |
| curr_rq_lock_irq_save(&flags); |
| cpu = smp_processor_id(); |
| |
| /* force the update of the task clock: */ |
| __task_delta_exec(curr, 1); |
| |
| perf_counter_task_sched_out(curr, cpu); |
| |
| spin_lock(&ctx->lock); |
| |
| /* |
| * Disable all the counters: |
| */ |
| perf_flags = hw_perf_save_disable(); |
| |
| list_for_each_entry(counter, &ctx->counter_list, list_entry) { |
| if (counter->state != PERF_COUNTER_STATE_OFF) |
| continue; |
| counter->state = PERF_COUNTER_STATE_INACTIVE; |
| counter->hw_event.disabled = 0; |
| } |
| hw_perf_restore(perf_flags); |
| |
| spin_unlock(&ctx->lock); |
| |
| perf_counter_task_sched_in(curr, cpu); |
| |
| curr_rq_unlock_irq_restore(&flags); |
| |
| return 0; |
| } |
| |
| /* |
| * Round-robin a context's counters: |
| */ |
| static void rotate_ctx(struct perf_counter_context *ctx) |
| { |
| struct perf_counter *counter; |
| u64 perf_flags; |
| |
| if (!ctx->nr_counters) |
| return; |
| |
| spin_lock(&ctx->lock); |
| /* |
| * Rotate the first entry last (works just fine for group counters too): |
| */ |
| perf_flags = hw_perf_save_disable(); |
| list_for_each_entry(counter, &ctx->counter_list, list_entry) { |
| list_del(&counter->list_entry); |
| list_add_tail(&counter->list_entry, &ctx->counter_list); |
| break; |
| } |
| hw_perf_restore(perf_flags); |
| |
| spin_unlock(&ctx->lock); |
| } |
| |
| void perf_counter_task_tick(struct task_struct *curr, int cpu) |
| { |
| struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); |
| struct perf_counter_context *ctx = &curr->perf_counter_ctx; |
| const int rotate_percpu = 0; |
| |
| if (rotate_percpu) |
| perf_counter_cpu_sched_out(cpuctx); |
| perf_counter_task_sched_out(curr, cpu); |
| |
| if (rotate_percpu) |
| rotate_ctx(&cpuctx->ctx); |
| rotate_ctx(ctx); |
| |
| if (rotate_percpu) |
| perf_counter_cpu_sched_in(cpuctx, cpu); |
| perf_counter_task_sched_in(curr, cpu); |
| } |
| |
| /* |
| * Cross CPU call to read the hardware counter |
| */ |
| static void __read(void *info) |
| { |
| struct perf_counter *counter = info; |
| unsigned long flags; |
| |
| curr_rq_lock_irq_save(&flags); |
| counter->hw_ops->read(counter); |
| curr_rq_unlock_irq_restore(&flags); |
| } |
| |
| static u64 perf_counter_read(struct perf_counter *counter) |
| { |
| /* |
| * If counter is enabled and currently active on a CPU, update the |
| * value in the counter structure: |
| */ |
| if (counter->state == PERF_COUNTER_STATE_ACTIVE) { |
| smp_call_function_single(counter->oncpu, |
| __read, counter, 1); |
| } |
| |
| return atomic64_read(&counter->count); |
| } |
| |
| /* |
| * Cross CPU call to switch performance data pointers |
| */ |
| static void __perf_switch_irq_data(void *info) |
| { |
| struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| struct perf_counter *counter = info; |
| struct perf_counter_context *ctx = counter->ctx; |
| struct perf_data *oldirqdata = counter->irqdata; |
| |
| /* |
| * If this is a task context, we need to check whether it is |
| * the current task context of this cpu. If not it has been |
| * scheduled out before the smp call arrived. |
| */ |
| if (ctx->task) { |
| if (cpuctx->task_ctx != ctx) |
| return; |
| spin_lock(&ctx->lock); |
| } |
| |
| /* Change the pointer NMI safe */ |
| atomic_long_set((atomic_long_t *)&counter->irqdata, |
| (unsigned long) counter->usrdata); |
| counter->usrdata = oldirqdata; |
| |
| if (ctx->task) |
| spin_unlock(&ctx->lock); |
| } |
| |
| static struct perf_data *perf_switch_irq_data(struct perf_counter *counter) |
| { |
| struct perf_counter_context *ctx = counter->ctx; |
| struct perf_data *oldirqdata = counter->irqdata; |
| struct task_struct *task = ctx->task; |
| |
| if (!task) { |
| smp_call_function_single(counter->cpu, |
| __perf_switch_irq_data, |
| counter, 1); |
| return counter->usrdata; |
| } |
| |
| retry: |
| spin_lock_irq(&ctx->lock); |
| if (counter->state != PERF_COUNTER_STATE_ACTIVE) { |
| counter->irqdata = counter->usrdata; |
| counter->usrdata = oldirqdata; |
| spin_unlock_irq(&ctx->lock); |
| return oldirqdata; |
| } |
| spin_unlock_irq(&ctx->lock); |
| task_oncpu_function_call(task, __perf_switch_irq_data, counter); |
| /* Might have failed, because task was scheduled out */ |
| if (counter->irqdata == oldirqdata) |
| goto retry; |
| |
| return counter->usrdata; |
| } |
| |
| static void put_context(struct perf_counter_context *ctx) |
| { |
| if (ctx->task) |
| put_task_struct(ctx->task); |
| } |
| |
| static struct perf_counter_context *find_get_context(pid_t pid, int cpu) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct perf_counter_context *ctx; |
| struct task_struct *task; |
| |
| /* |
| * If cpu is not a wildcard then this is a percpu counter: |
| */ |
| if (cpu != -1) { |
| /* Must be root to operate on a CPU counter: */ |
| if (!capable(CAP_SYS_ADMIN)) |
| return ERR_PTR(-EACCES); |
| |
| if (cpu < 0 || cpu > num_possible_cpus()) |
| return ERR_PTR(-EINVAL); |
| |
| /* |
| * We could be clever and allow to attach a counter to an |
| * offline CPU and activate it when the CPU comes up, but |
| * that's for later. |
| */ |
| if (!cpu_isset(cpu, cpu_online_map)) |
| return ERR_PTR(-ENODEV); |
| |
| cpuctx = &per_cpu(perf_cpu_context, cpu); |
| ctx = &cpuctx->ctx; |
| |
| return ctx; |
| } |
| |
| rcu_read_lock(); |
| if (!pid) |
| task = current; |
| else |
| task = find_task_by_vpid(pid); |
| if (task) |
| get_task_struct(task); |
| rcu_read_unlock(); |
| |
| if (!task) |
| return ERR_PTR(-ESRCH); |
| |
| ctx = &task->perf_counter_ctx; |
| ctx->task = task; |
| |
| /* Reuse ptrace permission checks for now. */ |
| if (!ptrace_may_access(task, PTRACE_MODE_READ)) { |
| put_context(ctx); |
| return ERR_PTR(-EACCES); |
| } |
| |
| return ctx; |
| } |
| |
| /* |
| * Called when the last reference to the file is gone. |
| */ |
| static int perf_release(struct inode *inode, struct file *file) |
| { |
| struct perf_counter *counter = file->private_data; |
| struct perf_counter_context *ctx = counter->ctx; |
| |
| file->private_data = NULL; |
| |
| mutex_lock(&counter->mutex); |
| |
| perf_counter_remove_from_context(counter); |
| put_context(ctx); |
| |
| mutex_unlock(&counter->mutex); |
| |
| kfree(counter); |
| |
| return 0; |
| } |
| |
| /* |
| * Read the performance counter - simple non blocking version for now |
| */ |
| static ssize_t |
| perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count) |
| { |
| u64 cntval; |
| |
| if (count != sizeof(cntval)) |
| return -EINVAL; |
| |
| mutex_lock(&counter->mutex); |
| cntval = perf_counter_read(counter); |
| mutex_unlock(&counter->mutex); |
| |
| return put_user(cntval, (u64 __user *) buf) ? -EFAULT : sizeof(cntval); |
| } |
| |
| static ssize_t |
| perf_copy_usrdata(struct perf_data *usrdata, char __user *buf, size_t count) |
| { |
| if (!usrdata->len) |
| return 0; |
| |
| count = min(count, (size_t)usrdata->len); |
| if (copy_to_user(buf, usrdata->data + usrdata->rd_idx, count)) |
| return -EFAULT; |
| |
| /* Adjust the counters */ |
| usrdata->len -= count; |
| if (!usrdata->len) |
| usrdata->rd_idx = 0; |
| else |
| usrdata->rd_idx += count; |
| |
| return count; |
| } |
| |
| static ssize_t |
| perf_read_irq_data(struct perf_counter *counter, |
| char __user *buf, |
| size_t count, |
| int nonblocking) |
| { |
| struct perf_data *irqdata, *usrdata; |
| DECLARE_WAITQUEUE(wait, current); |
| ssize_t res; |
| |
| irqdata = counter->irqdata; |
| usrdata = counter->usrdata; |
| |
| if (usrdata->len + irqdata->len >= count) |
| goto read_pending; |
| |
| if (nonblocking) |
| return -EAGAIN; |
| |
| spin_lock_irq(&counter->waitq.lock); |
| __add_wait_queue(&counter->waitq, &wait); |
| for (;;) { |
| set_current_state(TASK_INTERRUPTIBLE); |
| if (usrdata->len + irqdata->len >= count) |
| break; |
| |
| if (signal_pending(current)) |
| break; |
| |
| spin_unlock_irq(&counter->waitq.lock); |
| schedule(); |
| spin_lock_irq(&counter->waitq.lock); |
| } |
| __remove_wait_queue(&counter->waitq, &wait); |
| __set_current_state(TASK_RUNNING); |
| spin_unlock_irq(&counter->waitq.lock); |
| |
| if (usrdata->len + irqdata->len < count) |
| return -ERESTARTSYS; |
| read_pending: |
| mutex_lock(&counter->mutex); |
| |
| /* Drain pending data first: */ |
| res = perf_copy_usrdata(usrdata, buf, count); |
| if (res < 0 || res == count) |
| goto out; |
| |
| /* Switch irq buffer: */ |
| usrdata = perf_switch_irq_data(counter); |
| if (perf_copy_usrdata(usrdata, buf + res, count - res) < 0) { |
| if (!res) |
| res = -EFAULT; |
| } else { |
| res = count; |
| } |
| out: |
| mutex_unlock(&counter->mutex); |
| |
| return res; |
| } |
| |
| static ssize_t |
| perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct perf_counter *counter = file->private_data; |
| |
| switch (counter->hw_event.record_type) { |
| case PERF_RECORD_SIMPLE: |
| return perf_read_hw(counter, buf, count); |
| |
| case PERF_RECORD_IRQ: |
| case PERF_RECORD_GROUP: |
| return perf_read_irq_data(counter, buf, count, |
| file->f_flags & O_NONBLOCK); |
| } |
| return -EINVAL; |
| } |
| |
| static unsigned int perf_poll(struct file *file, poll_table *wait) |
| { |
| struct perf_counter *counter = file->private_data; |
| unsigned int events = 0; |
| unsigned long flags; |
| |
| poll_wait(file, &counter->waitq, wait); |
| |
| spin_lock_irqsave(&counter->waitq.lock, flags); |
| if (counter->usrdata->len || counter->irqdata->len) |
| events |= POLLIN; |
| spin_unlock_irqrestore(&counter->waitq.lock, flags); |
| |
| return events; |
| } |
| |
| static const struct file_operations perf_fops = { |
| .release = perf_release, |
| .read = perf_read, |
| .poll = perf_poll, |
| }; |
| |
| static int cpu_clock_perf_counter_enable(struct perf_counter *counter) |
| { |
| return 0; |
| } |
| |
| static void cpu_clock_perf_counter_disable(struct perf_counter *counter) |
| { |
| } |
| |
| static void cpu_clock_perf_counter_read(struct perf_counter *counter) |
| { |
| int cpu = raw_smp_processor_id(); |
| |
| atomic64_set(&counter->count, cpu_clock(cpu)); |
| } |
| |
| static const struct hw_perf_counter_ops perf_ops_cpu_clock = { |
| .enable = cpu_clock_perf_counter_enable, |
| .disable = cpu_clock_perf_counter_disable, |
| .read = cpu_clock_perf_counter_read, |
| }; |
| |
| /* |
| * Called from within the scheduler: |
| */ |
| static u64 task_clock_perf_counter_val(struct perf_counter *counter, int update) |
| { |
| struct task_struct *curr = counter->task; |
| u64 delta; |
| |
| delta = __task_delta_exec(curr, update); |
| |
| return curr->se.sum_exec_runtime + delta; |
| } |
| |
| static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now) |
| { |
| u64 prev; |
| s64 delta; |
| |
| prev = atomic64_read(&counter->hw.prev_count); |
| |
| atomic64_set(&counter->hw.prev_count, now); |
| |
| delta = now - prev; |
| |
| atomic64_add(delta, &counter->count); |
| } |
| |
| static void task_clock_perf_counter_read(struct perf_counter *counter) |
| { |
| u64 now = task_clock_perf_counter_val(counter, 1); |
| |
| task_clock_perf_counter_update(counter, now); |
| } |
| |
| static int task_clock_perf_counter_enable(struct perf_counter *counter) |
| { |
| u64 now = task_clock_perf_counter_val(counter, 0); |
| |
| atomic64_set(&counter->hw.prev_count, now); |
| |
| return 0; |
| } |
| |
| static void task_clock_perf_counter_disable(struct perf_counter *counter) |
| { |
| u64 now = task_clock_perf_counter_val(counter, 0); |
| |
| task_clock_perf_counter_update(counter, now); |
| } |
| |
| static const struct hw_perf_counter_ops perf_ops_task_clock = { |
| .enable = task_clock_perf_counter_enable, |
| .disable = task_clock_perf_counter_disable, |
| .read = task_clock_perf_counter_read, |
| }; |
| |
| static u64 get_page_faults(void) |
| { |
| struct task_struct *curr = current; |
| |
| return curr->maj_flt + curr->min_flt; |
| } |
| |
| static void page_faults_perf_counter_update(struct perf_counter *counter) |
| { |
| u64 prev, now; |
| s64 delta; |
| |
| prev = atomic64_read(&counter->hw.prev_count); |
| now = get_page_faults(); |
| |
| atomic64_set(&counter->hw.prev_count, now); |
| |
| delta = now - prev; |
| |
| atomic64_add(delta, &counter->count); |
| } |
| |
| static void page_faults_perf_counter_read(struct perf_counter *counter) |
| { |
| page_faults_perf_counter_update(counter); |
| } |
| |
| static int page_faults_perf_counter_enable(struct perf_counter *counter) |
| { |
| /* |
| * page-faults is a per-task value already, |
| * so we dont have to clear it on switch-in. |
| */ |
| |
| return 0; |
| } |
| |
| static void page_faults_perf_counter_disable(struct perf_counter *counter) |
| { |
| page_faults_perf_counter_update(counter); |
| } |
| |
| static const struct hw_perf_counter_ops perf_ops_page_faults = { |
| .enable = page_faults_perf_counter_enable, |
| .disable = page_faults_perf_counter_disable, |
| .read = page_faults_perf_counter_read, |
| }; |
| |
| static u64 get_context_switches(void) |
| { |
| struct task_struct *curr = current; |
| |
| return curr->nvcsw + curr->nivcsw; |
| } |
| |
| static void context_switches_perf_counter_update(struct perf_counter *counter) |
| { |
| u64 prev, now; |
| s64 delta; |
| |
| prev = atomic64_read(&counter->hw.prev_count); |
| now = get_context_switches(); |
| |
| atomic64_set(&counter->hw.prev_count, now); |
| |
| delta = now - prev; |
| |
| atomic64_add(delta, &counter->count); |
| } |
| |
| static void context_switches_perf_counter_read(struct perf_counter *counter) |
| { |
| context_switches_perf_counter_update(counter); |
| } |
| |
| static int context_switches_perf_counter_enable(struct perf_counter *counter) |
| { |
| /* |
| * ->nvcsw + curr->nivcsw is a per-task value already, |
| * so we dont have to clear it on switch-in. |
| */ |
| |
| return 0; |
| } |
| |
| static void context_switches_perf_counter_disable(struct perf_counter *counter) |
| { |
| context_switches_perf_counter_update(counter); |
| } |
| |
| static const struct hw_perf_counter_ops perf_ops_context_switches = { |
| .enable = context_switches_perf_counter_enable, |
| .disable = context_switches_perf_counter_disable, |
| .read = context_switches_perf_counter_read, |
| }; |
| |
| static inline u64 get_cpu_migrations(void) |
| { |
| return current->se.nr_migrations; |
| } |
| |
| static void cpu_migrations_perf_counter_update(struct perf_counter *counter) |
| { |
| u64 prev, now; |
| s64 delta; |
| |
| prev = atomic64_read(&counter->hw.prev_count); |
| now = get_cpu_migrations(); |
| |
| atomic64_set(&counter->hw.prev_count, now); |
| |
| delta = now - prev; |
| |
| atomic64_add(delta, &counter->count); |
| } |
| |
| static void cpu_migrations_perf_counter_read(struct perf_counter *counter) |
| { |
| cpu_migrations_perf_counter_update(counter); |
| } |
| |
| static int cpu_migrations_perf_counter_enable(struct perf_counter *counter) |
| { |
| /* |
| * se.nr_migrations is a per-task value already, |
| * so we dont have to clear it on switch-in. |
| */ |
| |
| return 0; |
| } |
| |
| static void cpu_migrations_perf_counter_disable(struct perf_counter *counter) |
| { |
| cpu_migrations_perf_counter_update(counter); |
| } |
| |
| static const struct hw_perf_counter_ops perf_ops_cpu_migrations = { |
| .enable = cpu_migrations_perf_counter_enable, |
| .disable = cpu_migrations_perf_counter_disable, |
| .read = cpu_migrations_perf_counter_read, |
| }; |
| |
| static const struct hw_perf_counter_ops * |
| sw_perf_counter_init(struct perf_counter *counter) |
| { |
| const struct hw_perf_counter_ops *hw_ops = NULL; |
| |
| switch (counter->hw_event.type) { |
| case PERF_COUNT_CPU_CLOCK: |
| hw_ops = &perf_ops_cpu_clock; |
| break; |
| case PERF_COUNT_TASK_CLOCK: |
| hw_ops = &perf_ops_task_clock; |
| break; |
| case PERF_COUNT_PAGE_FAULTS: |
| hw_ops = &perf_ops_page_faults; |
| break; |
| case PERF_COUNT_CONTEXT_SWITCHES: |
| hw_ops = &perf_ops_context_switches; |
| break; |
| case PERF_COUNT_CPU_MIGRATIONS: |
| hw_ops = &perf_ops_cpu_migrations; |
| break; |
| default: |
| break; |
| } |
| return hw_ops; |
| } |
| |
| /* |
| * Allocate and initialize a counter structure |
| */ |
| static struct perf_counter * |
| perf_counter_alloc(struct perf_counter_hw_event *hw_event, |
| int cpu, |
| struct perf_counter *group_leader, |
| gfp_t gfpflags) |
| { |
| const struct hw_perf_counter_ops *hw_ops; |
| struct perf_counter *counter; |
| |
| counter = kzalloc(sizeof(*counter), gfpflags); |
| if (!counter) |
| return NULL; |
| |
| /* |
| * Single counters are their own group leaders, with an |
| * empty sibling list: |
| */ |
| if (!group_leader) |
| group_leader = counter; |
| |
| mutex_init(&counter->mutex); |
| INIT_LIST_HEAD(&counter->list_entry); |
| INIT_LIST_HEAD(&counter->sibling_list); |
| init_waitqueue_head(&counter->waitq); |
| |
| counter->irqdata = &counter->data[0]; |
| counter->usrdata = &counter->data[1]; |
| counter->cpu = cpu; |
| counter->hw_event = *hw_event; |
| counter->wakeup_pending = 0; |
| counter->group_leader = group_leader; |
| counter->hw_ops = NULL; |
| |
| counter->state = PERF_COUNTER_STATE_INACTIVE; |
| if (hw_event->disabled) |
| counter->state = PERF_COUNTER_STATE_OFF; |
| |
| hw_ops = NULL; |
| if (!hw_event->raw && hw_event->type < 0) |
| hw_ops = sw_perf_counter_init(counter); |
| if (!hw_ops) |
| hw_ops = hw_perf_counter_init(counter); |
| |
| if (!hw_ops) { |
| kfree(counter); |
| return NULL; |
| } |
| counter->hw_ops = hw_ops; |
| |
| return counter; |
| } |
| |
| /** |
| * sys_perf_task_open - open a performance counter, associate it to a task/cpu |
| * |
| * @hw_event_uptr: event type attributes for monitoring/sampling |
| * @pid: target pid |
| * @cpu: target cpu |
| * @group_fd: group leader counter fd |
| */ |
| asmlinkage int |
| sys_perf_counter_open(struct perf_counter_hw_event *hw_event_uptr __user, |
| pid_t pid, int cpu, int group_fd) |
| { |
| struct perf_counter *counter, *group_leader; |
| struct perf_counter_hw_event hw_event; |
| struct perf_counter_context *ctx; |
| struct file *counter_file = NULL; |
| struct file *group_file = NULL; |
| int fput_needed = 0; |
| int fput_needed2 = 0; |
| int ret; |
| |
| if (copy_from_user(&hw_event, hw_event_uptr, sizeof(hw_event)) != 0) |
| return -EFAULT; |
| |
| /* |
| * Get the target context (task or percpu): |
| */ |
| ctx = find_get_context(pid, cpu); |
| if (IS_ERR(ctx)) |
| return PTR_ERR(ctx); |
| |
| /* |
| * Look up the group leader (we will attach this counter to it): |
| */ |
| group_leader = NULL; |
| if (group_fd != -1) { |
| ret = -EINVAL; |
| group_file = fget_light(group_fd, &fput_needed); |
| if (!group_file) |
| goto err_put_context; |
| if (group_file->f_op != &perf_fops) |
| goto err_put_context; |
| |
| group_leader = group_file->private_data; |
| /* |
| * Do not allow a recursive hierarchy (this new sibling |
| * becoming part of another group-sibling): |
| */ |
| if (group_leader->group_leader != group_leader) |
| goto err_put_context; |
| /* |
| * Do not allow to attach to a group in a different |
| * task or CPU context: |
| */ |
| if (group_leader->ctx != ctx) |
| goto err_put_context; |
| } |
| |
| ret = -EINVAL; |
| counter = perf_counter_alloc(&hw_event, cpu, group_leader, GFP_KERNEL); |
| if (!counter) |
| goto err_put_context; |
| |
| ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0); |
| if (ret < 0) |
| goto err_free_put_context; |
| |
| counter_file = fget_light(ret, &fput_needed2); |
| if (!counter_file) |
| goto err_free_put_context; |
| |
| counter->filp = counter_file; |
| perf_install_in_context(ctx, counter, cpu); |
| |
| fput_light(counter_file, fput_needed2); |
| |
| out_fput: |
| fput_light(group_file, fput_needed); |
| |
| return ret; |
| |
| err_free_put_context: |
| kfree(counter); |
| |
| err_put_context: |
| put_context(ctx); |
| |
| goto out_fput; |
| } |
| |
| /* |
| * Initialize the perf_counter context in a task_struct: |
| */ |
| static void |
| __perf_counter_init_context(struct perf_counter_context *ctx, |
| struct task_struct *task) |
| { |
| memset(ctx, 0, sizeof(*ctx)); |
| spin_lock_init(&ctx->lock); |
| INIT_LIST_HEAD(&ctx->counter_list); |
| ctx->task = task; |
| } |
| |
| /* |
| * inherit a counter from parent task to child task: |
| */ |
| static int |
| inherit_counter(struct perf_counter *parent_counter, |
| struct task_struct *parent, |
| struct perf_counter_context *parent_ctx, |
| struct task_struct *child, |
| struct perf_counter_context *child_ctx) |
| { |
| struct perf_counter *child_counter; |
| |
| child_counter = perf_counter_alloc(&parent_counter->hw_event, |
| parent_counter->cpu, NULL, |
| GFP_ATOMIC); |
| if (!child_counter) |
| return -ENOMEM; |
| |
| /* |
| * Link it up in the child's context: |
| */ |
| child_counter->ctx = child_ctx; |
| child_counter->task = child; |
| list_add_counter(child_counter, child_ctx); |
| child_ctx->nr_counters++; |
| |
| child_counter->parent = parent_counter; |
| /* |
| * inherit into child's child as well: |
| */ |
| child_counter->hw_event.inherit = 1; |
| |
| /* |
| * Get a reference to the parent filp - we will fput it |
| * when the child counter exits. This is safe to do because |
| * we are in the parent and we know that the filp still |
| * exists and has a nonzero count: |
| */ |
| atomic_long_inc(&parent_counter->filp->f_count); |
| |
| return 0; |
| } |
| |
| static void |
| __perf_counter_exit_task(struct task_struct *child, |
| struct perf_counter *child_counter, |
| struct perf_counter_context *child_ctx) |
| { |
| struct perf_counter *parent_counter; |
| u64 parent_val, child_val; |
| |
| /* |
| * If we do not self-reap then we have to wait for the |
| * child task to unschedule (it will happen for sure), |
| * so that its counter is at its final count. (This |
| * condition triggers rarely - child tasks usually get |
| * off their CPU before the parent has a chance to |
| * get this far into the reaping action) |
| */ |
| if (child != current) { |
| wait_task_inactive(child, 0); |
| list_del_init(&child_counter->list_entry); |
| } else { |
| struct perf_cpu_context *cpuctx; |
| unsigned long flags; |
| u64 perf_flags; |
| |
| /* |
| * Disable and unlink this counter. |
| * |
| * Be careful about zapping the list - IRQ/NMI context |
| * could still be processing it: |
| */ |
| curr_rq_lock_irq_save(&flags); |
| perf_flags = hw_perf_save_disable(); |
| |
| cpuctx = &__get_cpu_var(perf_cpu_context); |
| |
| if (child_counter->state == PERF_COUNTER_STATE_ACTIVE) { |
| child_counter->state = PERF_COUNTER_STATE_INACTIVE; |
| child_counter->hw_ops->disable(child_counter); |
| cpuctx->active_oncpu--; |
| child_ctx->nr_active--; |
| child_counter->oncpu = -1; |
| } |
| |
| list_del_init(&child_counter->list_entry); |
| |
| child_ctx->nr_counters--; |
| |
| hw_perf_restore(perf_flags); |
| curr_rq_unlock_irq_restore(&flags); |
| } |
| |
| parent_counter = child_counter->parent; |
| /* |
| * It can happen that parent exits first, and has counters |
| * that are still around due to the child reference. These |
| * counters need to be zapped - but otherwise linger. |
| */ |
| if (!parent_counter) |
| return; |
| |
| parent_val = atomic64_read(&parent_counter->count); |
| child_val = atomic64_read(&child_counter->count); |
| |
| /* |
| * Add back the child's count to the parent's count: |
| */ |
| atomic64_add(child_val, &parent_counter->count); |
| |
| fput(parent_counter->filp); |
| |
| kfree(child_counter); |
| } |
| |
| /* |
| * When a child task exist, feed back counter values to parent counters. |
| * |
| * Note: we are running in child context, but the PID is not hashed |
| * anymore so new counters will not be added. |
| */ |
| void perf_counter_exit_task(struct task_struct *child) |
| { |
| struct perf_counter *child_counter, *tmp; |
| struct perf_counter_context *child_ctx; |
| |
| child_ctx = &child->perf_counter_ctx; |
| |
| if (likely(!child_ctx->nr_counters)) |
| return; |
| |
| list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list, |
| list_entry) |
| __perf_counter_exit_task(child, child_counter, child_ctx); |
| } |
| |
| /* |
| * Initialize the perf_counter context in task_struct |
| */ |
| void perf_counter_init_task(struct task_struct *child) |
| { |
| struct perf_counter_context *child_ctx, *parent_ctx; |
| struct perf_counter *counter, *parent_counter; |
| struct task_struct *parent = current; |
| unsigned long flags; |
| |
| child_ctx = &child->perf_counter_ctx; |
| parent_ctx = &parent->perf_counter_ctx; |
| |
| __perf_counter_init_context(child_ctx, child); |
| |
| /* |
| * This is executed from the parent task context, so inherit |
| * counters that have been marked for cloning: |
| */ |
| |
| if (likely(!parent_ctx->nr_counters)) |
| return; |
| |
| /* |
| * Lock the parent list. No need to lock the child - not PID |
| * hashed yet and not running, so nobody can access it. |
| */ |
| spin_lock_irqsave(&parent_ctx->lock, flags); |
| |
| /* |
| * We dont have to disable NMIs - we are only looking at |
| * the list, not manipulating it: |
| */ |
| list_for_each_entry(counter, &parent_ctx->counter_list, list_entry) { |
| if (!counter->hw_event.inherit || counter->group_leader != counter) |
| continue; |
| |
| /* |
| * Instead of creating recursive hierarchies of counters, |
| * we link inheritd counters back to the original parent, |
| * which has a filp for sure, which we use as the reference |
| * count: |
| */ |
| parent_counter = counter; |
| if (counter->parent) |
| parent_counter = counter->parent; |
| |
| if (inherit_counter(parent_counter, parent, |
| parent_ctx, child, child_ctx)) |
| break; |
| } |
| |
| spin_unlock_irqrestore(&parent_ctx->lock, flags); |
| } |
| |
| static void __cpuinit perf_counter_init_cpu(int cpu) |
| { |
| struct perf_cpu_context *cpuctx; |
| |
| cpuctx = &per_cpu(perf_cpu_context, cpu); |
| __perf_counter_init_context(&cpuctx->ctx, NULL); |
| |
| mutex_lock(&perf_resource_mutex); |
| cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu; |
| mutex_unlock(&perf_resource_mutex); |
| |
| hw_perf_counter_setup(); |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| static void __perf_counter_exit_cpu(void *info) |
| { |
| struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
| struct perf_counter_context *ctx = &cpuctx->ctx; |
| struct perf_counter *counter, *tmp; |
| |
| list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry) |
| __perf_counter_remove_from_context(counter); |
| |
| } |
| static void perf_counter_exit_cpu(int cpu) |
| { |
| smp_call_function_single(cpu, __perf_counter_exit_cpu, NULL, 1); |
| } |
| #else |
| static inline void perf_counter_exit_cpu(int cpu) { } |
| #endif |
| |
| static int __cpuinit |
| perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) |
| { |
| unsigned int cpu = (long)hcpu; |
| |
| switch (action) { |
| |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| perf_counter_init_cpu(cpu); |
| break; |
| |
| case CPU_DOWN_PREPARE: |
| case CPU_DOWN_PREPARE_FROZEN: |
| perf_counter_exit_cpu(cpu); |
| break; |
| |
| default: |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block __cpuinitdata perf_cpu_nb = { |
| .notifier_call = perf_cpu_notify, |
| }; |
| |
| static int __init perf_counter_init(void) |
| { |
| perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE, |
| (void *)(long)smp_processor_id()); |
| register_cpu_notifier(&perf_cpu_nb); |
| |
| return 0; |
| } |
| early_initcall(perf_counter_init); |
| |
| static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf) |
| { |
| return sprintf(buf, "%d\n", perf_reserved_percpu); |
| } |
| |
| static ssize_t |
| perf_set_reserve_percpu(struct sysdev_class *class, |
| const char *buf, |
| size_t count) |
| { |
| struct perf_cpu_context *cpuctx; |
| unsigned long val; |
| int err, cpu, mpt; |
| |
| err = strict_strtoul(buf, 10, &val); |
| if (err) |
| return err; |
| if (val > perf_max_counters) |
| return -EINVAL; |
| |
| mutex_lock(&perf_resource_mutex); |
| perf_reserved_percpu = val; |
| for_each_online_cpu(cpu) { |
| cpuctx = &per_cpu(perf_cpu_context, cpu); |
| spin_lock_irq(&cpuctx->ctx.lock); |
| mpt = min(perf_max_counters - cpuctx->ctx.nr_counters, |
| perf_max_counters - perf_reserved_percpu); |
| cpuctx->max_pertask = mpt; |
| spin_unlock_irq(&cpuctx->ctx.lock); |
| } |
| mutex_unlock(&perf_resource_mutex); |
| |
| return count; |
| } |
| |
| static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf) |
| { |
| return sprintf(buf, "%d\n", perf_overcommit); |
| } |
| |
| static ssize_t |
| perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count) |
| { |
| unsigned long val; |
| int err; |
| |
| err = strict_strtoul(buf, 10, &val); |
| if (err) |
| return err; |
| if (val > 1) |
| return -EINVAL; |
| |
| mutex_lock(&perf_resource_mutex); |
| perf_overcommit = val; |
| mutex_unlock(&perf_resource_mutex); |
| |
| return count; |
| } |
| |
| static SYSDEV_CLASS_ATTR( |
| reserve_percpu, |
| 0644, |
| perf_show_reserve_percpu, |
| perf_set_reserve_percpu |
| ); |
| |
| static SYSDEV_CLASS_ATTR( |
| overcommit, |
| 0644, |
| perf_show_overcommit, |
| perf_set_overcommit |
| ); |
| |
| static struct attribute *perfclass_attrs[] = { |
| &attr_reserve_percpu.attr, |
| &attr_overcommit.attr, |
| NULL |
| }; |
| |
| static struct attribute_group perfclass_attr_group = { |
| .attrs = perfclass_attrs, |
| .name = "perf_counters", |
| }; |
| |
| static int __init perf_counter_sysfs_init(void) |
| { |
| return sysfs_create_group(&cpu_sysdev_class.kset.kobj, |
| &perfclass_attr_group); |
| } |
| device_initcall(perf_counter_sysfs_init); |