diff options
| -rw-r--r-- | include/linux/trace_events.h | 7 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 148 |
3 files changed, 154 insertions, 3 deletions
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index f85693bbcdc3..429fdfc3baf5 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -328,6 +328,7 @@ enum { EVENT_FILE_FL_SOFT_DISABLED_BIT, EVENT_FILE_FL_TRIGGER_MODE_BIT, EVENT_FILE_FL_TRIGGER_COND_BIT, + EVENT_FILE_FL_PID_FILTER_BIT, }; /* @@ -341,6 +342,7 @@ enum { * tracepoint may be enabled) * TRIGGER_MODE - When set, invoke the triggers associated with the event * TRIGGER_COND - When set, one or more triggers has an associated filter + * PID_FILTER - When set, the event is filtered based on pid */ enum { EVENT_FILE_FL_ENABLED = (1 << EVENT_FILE_FL_ENABLED_BIT), @@ -351,6 +353,7 @@ enum { EVENT_FILE_FL_SOFT_DISABLED = (1 << EVENT_FILE_FL_SOFT_DISABLED_BIT), EVENT_FILE_FL_TRIGGER_MODE = (1 << EVENT_FILE_FL_TRIGGER_MODE_BIT), EVENT_FILE_FL_TRIGGER_COND = (1 << EVENT_FILE_FL_TRIGGER_COND_BIT), + EVENT_FILE_FL_PID_FILTER = (1 << EVENT_FILE_FL_PID_FILTER_BIT), }; struct trace_event_file { @@ -429,6 +432,8 @@ extern enum event_trigger_type event_triggers_call(struct trace_event_file *file extern void event_triggers_post_call(struct trace_event_file *file, enum event_trigger_type tt); +bool trace_event_ignore_this_pid(struct trace_event_file *trace_file); + /** * trace_trigger_soft_disabled - do triggers and test if soft disabled * @file: The file pointer of the event to test @@ -448,6 +453,8 @@ trace_trigger_soft_disabled(struct trace_event_file *file) event_triggers_call(file, NULL); if (eflags & EVENT_FILE_FL_SOFT_DISABLED) return true; + if (eflags & EVENT_FILE_FL_PID_FILTER) + return trace_event_ignore_this_pid(file); } return false; } diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 250481043bb5..89ffdaf3e371 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -156,6 +156,8 @@ struct trace_array_cpu { pid_t pid; kuid_t uid; char comm[TASK_COMM_LEN]; + + bool ignore_pid; }; struct tracer; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 2ad7014707ee..ab07058e27c1 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -22,6 +22,8 @@ #include <linux/slab.h> #include <linux/delay.h> +#include <trace/events/sched.h> + #include <asm/setup.h> #include "trace_output.h" @@ -212,12 +214,32 @@ int trace_event_raw_init(struct trace_event_call *call) } EXPORT_SYMBOL_GPL(trace_event_raw_init); +bool trace_event_ignore_this_pid(struct trace_event_file *trace_file) +{ + struct trace_array *tr = trace_file->tr; + struct trace_array_cpu *data; + struct trace_pid_list *pid_list; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + if (!pid_list) + return false; + + data = this_cpu_ptr(tr->trace_buffer.data); + + return data->ignore_pid; +} +EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid); + void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer, struct trace_event_file *trace_file, unsigned long len) { struct trace_event_call *event_call = trace_file->event_call; + if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) && + trace_event_ignore_this_pid(trace_file)) + return NULL; + local_save_flags(fbuffer->flags); fbuffer->pc = preempt_count(); fbuffer->trace_file = trace_file; @@ -459,15 +481,114 @@ static int cmp_pid(const void *key, const void *elt) return 1; } +static bool +check_ignore_pid(struct trace_pid_list *filtered_pids, struct task_struct *task) +{ + pid_t search_pid; + pid_t *pid; + + /* + * Return false, because if filtered_pids does not exist, + * all pids are good to trace. + */ + if (!filtered_pids) + return false; + + search_pid = task->pid; + + pid = bsearch(&search_pid, filtered_pids->pids, + filtered_pids->nr_pids, sizeof(pid_t), + cmp_pid); + if (!pid) + return true; + + return false; +} + +static void +event_filter_pid_sched_switch_probe_pre(void *data, + struct task_struct *prev, struct task_struct *next) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, prev) && + check_ignore_pid(pid_list, next)); +} + +static void +event_filter_pid_sched_switch_probe_post(void *data, + struct task_struct *prev, struct task_struct *next) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, next)); +} + +static void +event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + /* Nothing to do if we are already tracing */ + if (!this_cpu_read(tr->trace_buffer.data->ignore_pid)) + return; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, task)); +} + +static void +event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + /* Nothing to do if we are not tracing */ + if (this_cpu_read(tr->trace_buffer.data->ignore_pid)) + return; + + pid_list = rcu_dereference_sched(tr->filtered_pids); + + /* Set tracing if current is enabled */ + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, current)); +} + static void __ftrace_clear_event_pids(struct trace_array *tr) { struct trace_pid_list *pid_list; + struct trace_event_file *file; + int cpu; pid_list = rcu_dereference_protected(tr->filtered_pids, lockdep_is_held(&event_mutex)); if (!pid_list) return; + unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr); + unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr); + + unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr); + unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr); + + list_for_each_entry(file, &tr->events, list) { + clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags); + } + + for_each_possible_cpu(cpu) + per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false; + rcu_assign_pointer(tr->filtered_pids, NULL); /* Wait till all users are no longer using pid filtering */ @@ -1429,13 +1550,14 @@ static int max_pids(struct trace_pid_list *pid_list) } static ssize_t -ftrace_event_pid_write(struct file *file, const char __user *ubuf, +ftrace_event_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - struct seq_file *m = file->private_data; + struct seq_file *m = filp->private_data; struct trace_array *tr = m->private; struct trace_pid_list *filtered_pids = NULL; struct trace_pid_list *pid_list = NULL; + struct trace_event_file *file; struct trace_parser parser; unsigned long val; loff_t this_pos; @@ -1564,15 +1686,35 @@ ftrace_event_pid_write(struct file *file, const char __user *ubuf, rcu_assign_pointer(tr->filtered_pids, pid_list); - mutex_unlock(&event_mutex); + list_for_each_entry(file, &tr->events, list) { + set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags); + } if (filtered_pids) { synchronize_sched(); free_pages((unsigned long)filtered_pids->pids, filtered_pids->order); kfree(filtered_pids); + } else { + /* + * Register a probe that is called before all other probes + * to set ignore_pid if next or prev do not match. + * Register a probe this is called after all other probes + * to only keep ignore_pid set if next pid matches. + */ + register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre, + tr, INT_MAX); + register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post, + tr, 0); + + register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, + tr, INT_MAX); + register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, + tr, 0); } + mutex_unlock(&event_mutex); + ret = read; *ppos += read; |