kernel/trace/trace.c

Source file repositories/reference/linux-study-clean/kernel/trace/trace.c

File Facts

System
Linux kernel
Corpus path
kernel/trace/trace.c
Extension
.c
Size
252494 bytes
Lines
10019
Domain
Core OS
Bucket
Scheduler, Processes, Timers, Sync, And Syscalls
Inferred role
Core OS: operation-table or driver-model contract
Status
pattern implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

static const struct file_operations tracing_fops = {
	.open		= tracing_open,
	.read		= seq_read,
	.read_iter	= seq_read_iter,
	.splice_read	= copy_splice_read,
	.write		= tracing_write_stub,
	.llseek		= tracing_lseek,
	.release	= tracing_release,
};

static const struct file_operations show_traces_fops = {
	.open		= show_traces_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= tracing_seq_release,
};

static ssize_t
tracing_cpumask_read(struct file *filp, char __user *ubuf,
		     size_t count, loff_t *ppos)
{
	struct trace_array *tr = file_inode(filp)->i_private;
	char *mask_str __free(kfree) = NULL;
	int len;

	len = snprintf(NULL, 0, "%*pb\n",
		       cpumask_pr_args(tr->tracing_cpumask)) + 1;
	mask_str = kmalloc(len, GFP_KERNEL);
	if (!mask_str)
		return -ENOMEM;

	len = snprintf(mask_str, len, "%*pb\n",
		       cpumask_pr_args(tr->tracing_cpumask));
	if (len >= count)
		return -EINVAL;

	return simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
}

int tracing_set_cpumask(struct trace_array *tr,
			cpumask_var_t tracing_cpumask_new)
{
	int cpu;

	if (!tr)
		return -EINVAL;

	local_irq_disable();
	arch_spin_lock(&tr->max_lock);
	for_each_tracing_cpu(cpu) {
		/*
		 * Increase/decrease the disabled counter if we are
		 * about to flip a bit in the cpumask:
		 */
		if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
			ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
#ifdef CONFIG_TRACER_SNAPSHOT
			ring_buffer_record_disable_cpu(tr->snapshot_buffer.buffer, cpu);
#endif
		}
		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
			ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
#ifdef CONFIG_TRACER_SNAPSHOT
			ring_buffer_record_enable_cpu(tr->snapshot_buffer.buffer, cpu);
#endif
		}
	}
	arch_spin_unlock(&tr->max_lock);
	local_irq_enable();

	cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);

	return 0;
}

static ssize_t
tracing_cpumask_write(struct file *filp, const char __user *ubuf,
		      size_t count, loff_t *ppos)
{
	struct trace_array *tr = file_inode(filp)->i_private;
	cpumask_var_t tracing_cpumask_new;
	int err;

	if (count == 0 || count > KMALLOC_MAX_SIZE)
		return -EINVAL;

	if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
		return -ENOMEM;

Annotation

Implementation Notes