115 lines
2.7 KiB
C
115 lines
2.7 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 "biostacks.h"
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#include "bits.bpf.h"
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#include "maps.bpf.h"
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#define MAX_ENTRIES 10240
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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 = -1;
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struct internal_rqinfo {
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u64 start_ts;
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struct rqinfo rqinfo;
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};
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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, struct internal_rqinfo);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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} rqinfos 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 rqinfo);
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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 struct hist zero;
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static __always_inline
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int trace_start(void *ctx, struct request *rq, bool merge_bio)
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{
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struct internal_rqinfo *i_rqinfop = NULL, i_rqinfo = {};
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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 (filter_dev && targ_dev != dev)
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return 0;
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if (merge_bio)
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i_rqinfop = bpf_map_lookup_elem(&rqinfos, &rq);
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if (!i_rqinfop)
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i_rqinfop = &i_rqinfo;
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i_rqinfop->start_ts = bpf_ktime_get_ns();
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i_rqinfop->rqinfo.pid = bpf_get_current_pid_tgid();
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i_rqinfop->rqinfo.kern_stack_size =
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bpf_get_stack(ctx, i_rqinfop->rqinfo.kern_stack,
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sizeof(i_rqinfop->rqinfo.kern_stack), 0);
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bpf_get_current_comm(&i_rqinfop->rqinfo.comm,
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sizeof(&i_rqinfop->rqinfo.comm));
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i_rqinfop->rqinfo.dev = dev;
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if (i_rqinfop == &i_rqinfo)
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bpf_map_update_elem(&rqinfos, &rq, i_rqinfop, 0);
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return 0;
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}
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SEC("fentry/blk_account_io_start")
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int BPF_PROG(blk_account_io_start, struct request *rq)
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{
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return trace_start(ctx, rq, false);
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}
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SEC("kprobe/blk_account_io_merge_bio")
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int BPF_KPROBE(blk_account_io_merge_bio, struct request *rq)
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{
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return trace_start(ctx, rq, true);
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}
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SEC("fentry/blk_account_io_done")
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int BPF_PROG(blk_account_io_done, struct request *rq)
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{
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u64 slot, ts = bpf_ktime_get_ns();
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struct internal_rqinfo *i_rqinfop;
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struct hist *histp;
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s64 delta;
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i_rqinfop = bpf_map_lookup_elem(&rqinfos, &rq);
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if (!i_rqinfop)
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return 0;
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delta = (s64)(ts - i_rqinfop->start_ts);
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if (delta < 0)
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goto cleanup;
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histp = bpf_map_lookup_or_try_init(&hists, &i_rqinfop->rqinfo, &zero);
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if (!histp)
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goto cleanup;
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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(&rqinfos, &rq);
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return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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