Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
tracing: Add reset to trace remotes
Allow to reset the trace remote buffer by writing to the Tracefs "trace"
file. This is similar to the regular Tracefs interface.
Link: https://patch.msgid.link/20260309162516.2623589-7-vdonnefort@google.com
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
authored by
Vincent Donnefort
and committed by
Steven Rostedt (Google)
9af4ab0e
96e43537
+48
+3
include/linux/trace_remote.h
+3
include/linux/trace_remote.h
···
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* remote to allow writing.
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* @swap_reader_page: Called when Tracefs consumes a new page from a
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* ring-buffer. It is expected from the remote to isolate a
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+
* @reset: Called on `echo 0 > trace`. It is expected from the
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* remote to reset all ring-buffer pages.
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* new reader-page from the @cpu ring-buffer.
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*/
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struct trace_remote_callbacks {
···
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void (*unload_trace_buffer)(struct trace_buffer_desc *desc, void *priv);
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int (*enable_tracing)(bool enable, void *priv);
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int (*swap_reader_page)(unsigned int cpu, void *priv);
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+
int (*reset)(unsigned int cpu, void *priv);
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};
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int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, void *priv);
+45
kernel/trace/trace_remote.c
+45
kernel/trace/trace_remote.c
···
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rb_remote->desc = desc;
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rb_remote->swap_reader_page = remote->cbs->swap_reader_page;
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rb_remote->priv = remote->priv;
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+
rb_remote->reset = remote->cbs->reset;
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remote->trace_buffer = ring_buffer_alloc_remote(rb_remote);
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if (!remote->trace_buffer) {
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remote->cbs->unload_trace_buffer(desc, remote->priv);
···
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trace_remote_try_unload(remote);
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return 0;
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+
}
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+
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static void trace_remote_reset(struct trace_remote *remote, int cpu)
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{
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lockdep_assert_held(&remote->lock);
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+
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if (!trace_remote_loaded(remote))
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return;
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+
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if (cpu == RING_BUFFER_ALL_CPUS)
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ring_buffer_reset(remote->trace_buffer);
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else
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ring_buffer_reset_cpu(remote->trace_buffer, cpu);
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+
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trace_remote_try_unload(remote);
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}
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static ssize_t
···
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.release = trace_pipe_release,
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};
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+
static ssize_t trace_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
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+
{
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struct inode *inode = file_inode(filp);
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struct trace_remote *remote = inode->i_private;
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int cpu = RING_BUFFER_ALL_CPUS;
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+
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if (inode->i_cdev)
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cpu = (long)inode->i_cdev - 1;
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+
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+
guard(mutex)(&remote->lock);
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+
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trace_remote_reset(remote, cpu);
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+
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return cnt;
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}
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+
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static const struct file_operations trace_fops = {
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.write = trace_write,
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+
};
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+
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static int trace_remote_init_tracefs(const char *name, struct trace_remote *remote)
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{
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struct dentry *remote_d, *percpu_d, *d;
···
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if (!d)
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goto err;
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+
d = trace_create_file("trace", TRACEFS_MODE_WRITE, remote_d, remote, &trace_fops);
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if (!d)
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goto err;
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+
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percpu_d = tracefs_create_dir("per_cpu", remote_d);
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if (!percpu_d) {
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pr_err("Failed to create tracefs dir "TRACEFS_DIR"%s/per_cpu/\n", name);
···
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d = trace_create_cpu_file("trace_pipe", TRACEFS_MODE_READ, cpu_d, remote, cpu,
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&trace_pipe_fops);
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+
if (!d)
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goto err;
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+
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d = trace_create_cpu_file("trace", TRACEFS_MODE_WRITE, cpu_d, remote, cpu,
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&trace_fops);
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if (!d)
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goto err;
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}