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-rw-r--r--kernel/trace/trace.c214
1 files changed, 182 insertions, 32 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6a0ee9178365..02a23a6e5e00 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -45,6 +45,9 @@
#include <linux/trace.h>
#include <linux/sched/clock.h>
#include <linux/sched/rt.h>
+#include <linux/fsnotify.h>
+#include <linux/irq_work.h>
+#include <linux/workqueue.h>
#include "trace.h"
#include "trace_output.h"
@@ -298,12 +301,24 @@ static void __trace_array_put(struct trace_array *this_tr)
this_tr->ref--;
}
+/**
+ * trace_array_put - Decrement the reference counter for this trace array.
+ *
+ * NOTE: Use this when we no longer need the trace array returned by
+ * trace_array_get_by_name(). This ensures the trace array can be later
+ * destroyed.
+ *
+ */
void trace_array_put(struct trace_array *this_tr)
{
+ if (!this_tr)
+ return;
+
mutex_lock(&trace_types_lock);
__trace_array_put(this_tr);
mutex_unlock(&trace_types_lock);
}
+EXPORT_SYMBOL_GPL(trace_array_put);
int tracing_check_open_get_tr(struct trace_array *tr)
{
@@ -1497,6 +1512,74 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
}
unsigned long __read_mostly tracing_thresh;
+static const struct file_operations tracing_max_lat_fops;
+
+#if (defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)) && \
+ defined(CONFIG_FSNOTIFY)
+
+static struct workqueue_struct *fsnotify_wq;
+
+static void latency_fsnotify_workfn(struct work_struct *work)
+{
+ struct trace_array *tr = container_of(work, struct trace_array,
+ fsnotify_work);
+ fsnotify(tr->d_max_latency->d_inode, FS_MODIFY,
+ tr->d_max_latency->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+}
+
+static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
+{
+ struct trace_array *tr = container_of(iwork, struct trace_array,
+ fsnotify_irqwork);
+ queue_work(fsnotify_wq, &tr->fsnotify_work);
+}
+
+static void trace_create_maxlat_file(struct trace_array *tr,
+ struct dentry *d_tracer)
+{
+ INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
+ init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
+ tr->d_max_latency = trace_create_file("tracing_max_latency", 0644,
+ d_tracer, &tr->max_latency,
+ &tracing_max_lat_fops);
+}
+
+__init static int latency_fsnotify_init(void)
+{
+ fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
+ WQ_UNBOUND | WQ_HIGHPRI, 0);
+ if (!fsnotify_wq) {
+ pr_err("Unable to allocate tr_max_lat_wq\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+late_initcall_sync(latency_fsnotify_init);
+
+void latency_fsnotify(struct trace_array *tr)
+{
+ if (!fsnotify_wq)
+ return;
+ /*
+ * We cannot call queue_work(&tr->fsnotify_work) from here because it's
+ * possible that we are called from __schedule() or do_idle(), which
+ * could cause a deadlock.
+ */
+ irq_work_queue(&tr->fsnotify_irqwork);
+}
+
+/*
+ * (defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)) && \
+ * defined(CONFIG_FSNOTIFY)
+ */
+#else
+
+#define trace_create_maxlat_file(tr, d_tracer) \
+ trace_create_file("tracing_max_latency", 0644, d_tracer, \
+ &tr->max_latency, &tracing_max_lat_fops)
+
+#endif
#ifdef CONFIG_TRACER_MAX_TRACE
/*
@@ -1536,6 +1619,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
/* record this tasks comm */
tracing_record_cmdline(tsk);
+ latency_fsnotify(tr);
}
/**
@@ -3225,6 +3309,9 @@ int trace_array_printk(struct trace_array *tr,
if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
return 0;
+ if (!tr)
+ return -ENOENT;
+
va_start(ap, fmt);
ret = trace_array_vprintk(tr, ip, fmt, ap);
va_end(ap);
@@ -3654,6 +3741,8 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter)
"desktop",
#elif defined(CONFIG_PREEMPT)
"preempt",
+#elif defined(CONFIG_PREEMPT_RT)
+ "preempt_rt",
#else
"unknown",
#endif
@@ -4609,7 +4698,7 @@ int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
if (mask == TRACE_ITER_RECORD_TGID) {
if (!tgid_map)
- tgid_map = kcalloc(PID_MAX_DEFAULT + 1,
+ tgid_map = kvcalloc(PID_MAX_DEFAULT + 1,
sizeof(*tgid_map),
GFP_KERNEL);
if (!tgid_map) {
@@ -7583,14 +7672,23 @@ static ssize_t
tracing_read_dyn_info(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- unsigned long *p = filp->private_data;
- char buf[64]; /* Not too big for a shallow stack */
+ ssize_t ret;
+ char *buf;
int r;
- r = scnprintf(buf, 63, "%ld", *p);
- buf[r++] = '\n';
+ /* 256 should be plenty to hold the amount needed */
+ buf = kmalloc(256, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
- return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+ r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
+ ftrace_update_tot_cnt,
+ ftrace_number_of_pages,
+ ftrace_number_of_groups);
+
+ ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+ kfree(buf);
+ return ret;
}
static const struct file_operations tracing_dyn_info_fops = {
@@ -8351,24 +8449,15 @@ static void update_tracer_options(struct trace_array *tr)
mutex_unlock(&trace_types_lock);
}
-struct trace_array *trace_array_create(const char *name)
+static struct trace_array *trace_array_create(const char *name)
{
struct trace_array *tr;
int ret;
- mutex_lock(&event_mutex);
- mutex_lock(&trace_types_lock);
-
- ret = -EEXIST;
- list_for_each_entry(tr, &ftrace_trace_arrays, list) {
- if (tr->name && strcmp(tr->name, name) == 0)
- goto out_unlock;
- }
-
ret = -ENOMEM;
tr = kzalloc(sizeof(*tr), GFP_KERNEL);
if (!tr)
- goto out_unlock;
+ return ERR_PTR(ret);
tr->name = kstrdup(name, GFP_KERNEL);
if (!tr->name)
@@ -8413,8 +8502,8 @@ struct trace_array *trace_array_create(const char *name)
list_add(&tr->list, &ftrace_trace_arrays);
- mutex_unlock(&trace_types_lock);
- mutex_unlock(&event_mutex);
+ tr->ref++;
+
return tr;
@@ -8424,24 +8513,77 @@ struct trace_array *trace_array_create(const char *name)
kfree(tr->name);
kfree(tr);
- out_unlock:
- mutex_unlock(&trace_types_lock);
- mutex_unlock(&event_mutex);
-
return ERR_PTR(ret);
}
-EXPORT_SYMBOL_GPL(trace_array_create);
static int instance_mkdir(const char *name)
{
- return PTR_ERR_OR_ZERO(trace_array_create(name));
+ struct trace_array *tr;
+ int ret;
+
+ mutex_lock(&event_mutex);
+ mutex_lock(&trace_types_lock);
+
+ ret = -EEXIST;
+ list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+ if (tr->name && strcmp(tr->name, name) == 0)
+ goto out_unlock;
+ }
+
+ tr = trace_array_create(name);
+
+ ret = PTR_ERR_OR_ZERO(tr);
+
+out_unlock:
+ mutex_unlock(&trace_types_lock);
+ mutex_unlock(&event_mutex);
+ return ret;
+}
+
+/**
+ * trace_array_get_by_name - Create/Lookup a trace array, given its name.
+ * @name: The name of the trace array to be looked up/created.
+ *
+ * Returns pointer to trace array with given name.
+ * NULL, if it cannot be created.
+ *
+ * NOTE: This function increments the reference counter associated with the
+ * trace array returned. This makes sure it cannot be freed while in use.
+ * Use trace_array_put() once the trace array is no longer needed.
+ *
+ */
+struct trace_array *trace_array_get_by_name(const char *name)
+{
+ struct trace_array *tr;
+
+ mutex_lock(&event_mutex);
+ mutex_lock(&trace_types_lock);
+
+ list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+ if (tr->name && strcmp(tr->name, name) == 0)
+ goto out_unlock;
+ }
+
+ tr = trace_array_create(name);
+
+ if (IS_ERR(tr))
+ tr = NULL;
+out_unlock:
+ if (tr)
+ tr->ref++;
+
+ mutex_unlock(&trace_types_lock);
+ mutex_unlock(&event_mutex);
+ return tr;
}
+EXPORT_SYMBOL_GPL(trace_array_get_by_name);
static int __remove_instance(struct trace_array *tr)
{
int i;
- if (tr->ref || (tr->current_trace && tr->current_trace->ref))
+ /* Reference counter for a newly created trace array = 1. */
+ if (tr->ref > 1 || (tr->current_trace && tr->current_trace->ref))
return -EBUSY;
list_del(&tr->list);
@@ -8473,17 +8615,26 @@ static int __remove_instance(struct trace_array *tr)
return 0;
}
-int trace_array_destroy(struct trace_array *tr)
+int trace_array_destroy(struct trace_array *this_tr)
{
+ struct trace_array *tr;
int ret;
- if (!tr)
+ if (!this_tr)
return -EINVAL;
mutex_lock(&event_mutex);
mutex_lock(&trace_types_lock);
- ret = __remove_instance(tr);
+ ret = -ENODEV;
+
+ /* Making sure trace array exists before destroying it. */
+ list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+ if (tr == this_tr) {
+ ret = __remove_instance(tr);
+ break;
+ }
+ }
mutex_unlock(&trace_types_lock);
mutex_unlock(&event_mutex);
@@ -8585,8 +8736,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
create_trace_options_dir(tr);
#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
- trace_create_file("tracing_max_latency", 0644, d_tracer,
- &tr->max_latency, &tracing_max_lat_fops);
+ trace_create_maxlat_file(tr, d_tracer);
#endif
if (ftrace_create_function_files(tr, d_tracer))
@@ -8782,7 +8932,7 @@ static __init int tracer_init_tracefs(void)
#ifdef CONFIG_DYNAMIC_FTRACE
trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
- &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
+ NULL, &tracing_dyn_info_fops);
#endif
create_trace_instances(d_tracer);