#! /usr/bin/python3
#
# oomkill Trace oom_kill_process(). For Linux, uses BCC, 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 OOM.
#
# Copyright 2016 Netflix, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 09-Feb-2016 Brendan Gregg Created this.
from bcc import BPF
from time import strftime
# linux stats
loadavg = "/proc/loadavg"
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
#include <linux/oom.h>
struct data_t {
u32 fpid;
u32 tpid;
u64 pages;
char fcomm[TASK_COMM_LEN];
char tcomm[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(events);
void kprobe__oom_kill_process(struct pt_regs *ctx, struct oom_control *oc, const char *message)
{
struct task_struct *p = oc->chosen;
struct data_t data = {};
u32 pid = bpf_get_current_pid_tgid() >> 32;
data.fpid = pid;
data.tpid = p->tgid;
data.pages = oc->totalpages;
bpf_get_current_comm(&data.fcomm, sizeof(data.fcomm));
bpf_probe_read_kernel(&data.tcomm, sizeof(data.tcomm), p->comm);
events.perf_submit(ctx, &data, sizeof(data));
}
"""
# process event
def print_event(cpu, data, size):
event = b["events"].event(data)
with open(loadavg) as stats:
avgline = stats.read().rstrip()
print(("%s Triggered by PID %d (\"%s\"), OOM kill of PID %d (\"%s\")"
", %d pages, loadavg: %s") % (strftime("%H:%M:%S"), event.fpid,
event.fcomm.decode('utf-8', 'replace'), event.tpid,
event.tcomm.decode('utf-8', 'replace'), event.pages, avgline))
# initialize BPF
b = BPF(text=bpf_text)
print("Tracing OOM kills... Ctrl-C to stop.")
b["events"].open_perf_buffer(print_event)
while 1:
try:
b.perf_buffer_poll()
except KeyboardInterrupt:
exit()
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