153 lines
3.6 KiB
C
153 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2020 Wenbo Zhang
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_core_read.h>
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#include <bpf/bpf_tracing.h>
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#include "biolatency.h"
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#include "bits.bpf.h"
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#define MAX_ENTRIES 10240
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extern int LINUX_KERNEL_VERSION __kconfig;
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const volatile bool filter_cg = false;
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const volatile bool targ_per_disk = false;
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const volatile bool targ_per_flag = false;
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const volatile bool targ_queued = false;
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const volatile bool targ_ms = false;
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const volatile bool filter_dev = false;
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const volatile __u32 targ_dev = 0;
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struct {
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__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
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__type(key, u32);
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__type(value, u32);
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__uint(max_entries, 1);
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} cgroup_map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, MAX_ENTRIES);
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__type(key, struct request *);
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__type(value, u64);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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} start SEC(".maps");
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static struct hist initial_hist;
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, MAX_ENTRIES);
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__type(key, struct hist_key);
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__type(value, struct hist);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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} hists SEC(".maps");
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static __always_inline
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int trace_rq_start(struct request *rq, int issue)
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{
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if (issue && targ_queued && BPF_CORE_READ(rq->q, elevator))
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return 0;
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u64 ts = bpf_ktime_get_ns();
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if (filter_dev) {
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struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
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u32 dev;
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dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
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BPF_CORE_READ(disk, first_minor)) : 0;
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if (targ_dev != dev)
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return 0;
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}
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bpf_map_update_elem(&start, &rq, &ts, 0);
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return 0;
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}
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SEC("tp_btf/block_rq_insert")
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int block_rq_insert(u64 *ctx)
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{
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if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
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return 0;
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/**
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* commit a54895fa (v5.11-rc1) changed tracepoint argument list
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* from TP_PROTO(struct request_queue *q, struct request *rq)
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* to TP_PROTO(struct request *rq)
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*/
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if (LINUX_KERNEL_VERSION <= KERNEL_VERSION(5, 10, 0))
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return trace_rq_start((void *)ctx[1], false);
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else
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return trace_rq_start((void *)ctx[0], false);
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}
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SEC("tp_btf/block_rq_issue")
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int block_rq_issue(u64 *ctx)
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{
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if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
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return 0;
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/**
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* commit a54895fa (v5.11-rc1) changed tracepoint argument list
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* from TP_PROTO(struct request_queue *q, struct request *rq)
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* to TP_PROTO(struct request *rq)
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*/
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if (LINUX_KERNEL_VERSION <= KERNEL_VERSION(5, 10, 0))
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return trace_rq_start((void *)ctx[1], true);
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else
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return trace_rq_start((void *)ctx[0], true);
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}
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SEC("tp_btf/block_rq_complete")
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int BPF_PROG(block_rq_complete, struct request *rq, int error,
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unsigned int nr_bytes)
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{
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if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
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return 0;
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u64 slot, *tsp, ts = bpf_ktime_get_ns();
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struct hist_key hkey = {};
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struct hist *histp;
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s64 delta;
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tsp = bpf_map_lookup_elem(&start, &rq);
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if (!tsp)
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return 0;
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delta = (s64)(ts - *tsp);
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if (delta < 0)
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goto cleanup;
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if (targ_per_disk) {
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struct gendisk *disk = BPF_CORE_READ(rq, rq_disk);
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hkey.dev = disk ? MKDEV(BPF_CORE_READ(disk, major),
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BPF_CORE_READ(disk, first_minor)) : 0;
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}
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if (targ_per_flag)
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hkey.cmd_flags = rq->cmd_flags;
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histp = bpf_map_lookup_elem(&hists, &hkey);
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if (!histp) {
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bpf_map_update_elem(&hists, &hkey, &initial_hist, 0);
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histp = bpf_map_lookup_elem(&hists, &hkey);
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if (!histp)
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goto cleanup;
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}
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if (targ_ms)
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delta /= 1000000U;
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else
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delta /= 1000U;
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slot = log2l(delta);
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if (slot >= MAX_SLOTS)
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slot = MAX_SLOTS - 1;
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__sync_fetch_and_add(&histp->slots[slot], 1);
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cleanup:
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bpf_map_delete_elem(&start, &rq);
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return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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