mdflush.bt

#!/usr/bin/env bpftrace
/*
 * mdflush	Trace md flush events.
 *		For Linux, uses bpftrace and eBPF.
 *
 * USAGE: mdflush.bt
 *
 * This is a bpftrace version of the bcc tool of the same name.
 *
 * Copyright 2018 Netflix, Inc.
 * Licensed under the Apache License, Version 2.0 (the "License")
 *
 * 08-Sep-2018	Brendan Gregg	Created this.
 */

#include <linux/genhd.h>
#include <linux/bio.h>

BEGIN
{
	printf("Tracing md flush events... Hit Ctrl-C to end.\n");
	printf("%-8s %-6s %-16s %s", "TIME", "PID", "COMM", "DEVICE");
}

kprobe:md_flush_request
{
	time("%H:%M:%S ");
	printf("%-6d %-16s %s\n", pid, comm,
	    ((struct bio *)arg1)->bi_disk->disk_name);
}