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11430421b4
The existing tracing programs have been developed for a considerable period of time and, as a result, do not properly incorporate the features of the current libbpf, such as CO-RE. This is evident in frequent usage of functions like PT_REGS* and the persistence of "hack" methods using underscore-style bpf_probe_read_kernel from the past. These programs are far behind the current level of libbpf and can potentially confuse users. Therefore, this commit aims to convert the outdated BPF programs to be more CO-RE centric. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Link: https://lore.kernel.org/r/20230818090119.477441-6-danieltimlee@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
142 lines
3.3 KiB
C
142 lines
3.3 KiB
C
/* Copyright (c) 2016 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include "vmlinux.h"
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#include <linux/version.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#ifndef PERF_MAX_STACK_DEPTH
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#define PERF_MAX_STACK_DEPTH 127
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#endif
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#define MINBLOCK_US 1
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#define MAX_ENTRIES 10000
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struct key_t {
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char waker[TASK_COMM_LEN];
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char target[TASK_COMM_LEN];
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u32 wret;
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u32 tret;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, struct key_t);
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__type(value, u64);
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__uint(max_entries, MAX_ENTRIES);
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} counts SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, u32);
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__type(value, u64);
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__uint(max_entries, MAX_ENTRIES);
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} start SEC(".maps");
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struct wokeby_t {
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char name[TASK_COMM_LEN];
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u32 ret;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, u32);
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__type(value, struct wokeby_t);
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__uint(max_entries, MAX_ENTRIES);
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} wokeby SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_STACK_TRACE);
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__uint(key_size, sizeof(u32));
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__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
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__uint(max_entries, MAX_ENTRIES);
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} stackmap SEC(".maps");
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#define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
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SEC("kprobe/try_to_wake_up")
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int waker(struct pt_regs *ctx)
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{
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struct task_struct *p = (void *)PT_REGS_PARM1_CORE(ctx);
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u32 pid = BPF_CORE_READ(p, pid);
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struct wokeby_t woke;
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bpf_get_current_comm(&woke.name, sizeof(woke.name));
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woke.ret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
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bpf_map_update_elem(&wokeby, &pid, &woke, BPF_ANY);
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return 0;
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}
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static inline int update_counts(void *ctx, u32 pid, u64 delta)
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{
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struct wokeby_t *woke;
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u64 zero = 0, *val;
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struct key_t key;
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__builtin_memset(&key.waker, 0, sizeof(key.waker));
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bpf_get_current_comm(&key.target, sizeof(key.target));
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key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
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key.wret = 0;
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woke = bpf_map_lookup_elem(&wokeby, &pid);
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if (woke) {
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key.wret = woke->ret;
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__builtin_memcpy(&key.waker, woke->name, sizeof(key.waker));
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bpf_map_delete_elem(&wokeby, &pid);
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}
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val = bpf_map_lookup_elem(&counts, &key);
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if (!val) {
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bpf_map_update_elem(&counts, &key, &zero, BPF_NOEXIST);
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val = bpf_map_lookup_elem(&counts, &key);
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if (!val)
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return 0;
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}
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(*val) += delta;
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return 0;
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}
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#if 1
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/* taken from /sys/kernel/tracing/events/sched/sched_switch/format */
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SEC("tracepoint/sched/sched_switch")
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int oncpu(struct trace_event_raw_sched_switch *ctx)
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{
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/* record previous thread sleep time */
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u32 pid = ctx->prev_pid;
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#else
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SEC("kprobe.multi/finish_task_switch*")
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int oncpu(struct pt_regs *ctx)
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{
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struct task_struct *p = (void *)PT_REGS_PARM1_CORE(ctx);
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/* record previous thread sleep time */
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u32 pid = BPF_CORE_READ(p, pid);
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#endif
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u64 delta, ts, *tsp;
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ts = bpf_ktime_get_ns();
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bpf_map_update_elem(&start, &pid, &ts, BPF_ANY);
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/* calculate current thread's delta time */
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pid = bpf_get_current_pid_tgid();
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tsp = bpf_map_lookup_elem(&start, &pid);
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if (!tsp)
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/* missed start or filtered */
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return 0;
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delta = bpf_ktime_get_ns() - *tsp;
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bpf_map_delete_elem(&start, &pid);
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delta = delta / 1000;
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if (delta < MINBLOCK_US)
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return 0;
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return update_counts(ctx, pid, delta);
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}
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char _license[] SEC("license") = "GPL";
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u32 _version SEC("version") = LINUX_VERSION_CODE;
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