#!/usr/bin/env bpftrace
/*
 * oomkill	Trace OOM killer.
 *		For Linux, uses bpftrace and eBPF.
 *
 * This traces the kernel out-of-memory killer, and prints basic details,
 * including the system load averages. This can provide more context on the
 * system state at the time of OOM: was it getting busier or steady, based
 * on the load averages? This tool may also be useful to customize for
 * investigations; for example, by adding other task_struct details at the
 * time of the OOM, or other commands in the system() call.
 *
 * This currently works by using kernel dynamic tracing of oom_kill_process().
 *
 * USAGE: oomkill.bt
 *
 * Copyright 2018 Netflix, Inc.
 * Licensed under the Apache License, Version 2.0 (the "License")
 *
 * 07-Sep-2018	Brendan Gregg	Created this.
 */

#ifndef BPFTRACE_HAVE_BTF
#include <linux/oom.h>
#endif

BEGIN
{
	printf("Tracing oom_kill_process()... Hit Ctrl-C to end.\n");
}

kprobe:oom_kill_process
{
	$oc = (struct oom_control *)arg0;
	time("%H:%M:%S ");
	printf("Triggered by PID %d (\"%s\"), ", pid, comm);
	printf("OOM kill of PID %d (\"%s\"), %d pages, loadavg: ",
	    $oc->chosen->pid, $oc->chosen->comm, $oc->totalpages);
	cat("/proc/loadavg");
}