50 lines
1.0 KiB
C
50 lines
1.0 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_tracing.h>
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 10240);
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__type(key, u32);
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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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__u64 latency = 0;
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__u64 num = 0;
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SEC("fentry/migrate_misplaced_page")
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int BPF_PROG(migrate_misplaced_page)
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{
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u32 pid = bpf_get_current_pid_tgid();
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u64 ts = bpf_ktime_get_ns();
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bpf_map_update_elem(&start, &pid, &ts, 0);
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return 0;
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}
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SEC("fexit/migrate_misplaced_page")
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int BPF_PROG(migrate_misplaced_page_exit)
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{
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u32 pid = bpf_get_current_pid_tgid();
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u64 *tsp, ts = bpf_ktime_get_ns();
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s64 delta;
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tsp = bpf_map_lookup_elem(&start, &pid);
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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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__sync_fetch_and_add(&latency, delta / 1000000U);
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__sync_fetch_and_add(&num, 1);
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cleanup:
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bpf_map_delete_elem(&start, &pid);
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return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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