pagers-core 0.1.4

Core library for page cache diagnostics and control on Linux and macOS
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

pub(crate) trait SeenInodes {
    fn already_seen(&self, key: (u64, u64)) -> bool;
}

#[cfg(feature = "rayon")]
mod rayon_impl {
    use std::num::NonZeroU16;

    #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
    #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
    pub enum Threads {
        #[default]
        All,
        Exact(NonZeroU16),
    }

    impl From<u16> for Threads {
        fn from(n: u16) -> Self {
            match NonZeroU16::new(n) {
                None => Self::All,
                Some(n) => Self::Exact(n),
            }
        }
    }

    impl std::fmt::Display for Threads {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
            match self {
                Self::All => f.write_str("0"),
                Self::Exact(n) => write!(f, "{n}"),
            }
        }
    }

    impl std::str::FromStr for Threads {
        type Err = std::num::ParseIntError;

        fn from_str(s: &str) -> Result<Self, Self::Err> {
            let n: u16 = s.parse()?;
            Ok(Self::from(n))
        }
    }

    impl Threads {
        pub fn num_threads(self) -> usize {
            match self {
                Self::All => 0,
                Self::Exact(n) => n.get() as usize,
            }
        }
    }

    impl super::SeenInodes for dashmap::DashMap<(u64, u64), ()> {
        fn already_seen(&self, key: (u64, u64)) -> bool {
            self.insert(key, ()).is_some()
        }
    }

    pub(crate) type InodeSet = dashmap::DashMap<(u64, u64), ()>;
}

#[cfg(feature = "rayon")]
pub(crate) use rayon_impl::InodeSet;
#[cfg(feature = "rayon")]
pub use rayon_impl::Threads;

#[cfg(not(feature = "rayon"))]
impl SeenInodes for std::cell::RefCell<std::collections::HashSet<(u64, u64)>> {
    fn already_seen(&self, key: (u64, u64)) -> bool {
        !self.borrow_mut().insert(key)
    }
}

#[cfg(not(feature = "rayon"))]
pub(crate) type InodeSet = std::cell::RefCell<std::collections::HashSet<(u64, u64)>>;

#[cfg(test)]
#[cfg(feature = "rayon")]
mod tests {
    use std::num::NonZeroU16;

    use super::*;

    fn exact(n: u16) -> Threads {
        Threads::Exact(NonZeroU16::new(n).unwrap())
    }

    #[test]
    fn threads_from_zero_is_all() {
        assert_eq!(Threads::from(0), Threads::All);
    }

    #[test]
    fn threads_from_nonzero_is_exact() {
        assert_eq!(Threads::from(4), exact(4));
        assert_eq!(Threads::from(1), exact(1));
    }

    #[test]
    fn threads_default_is_all() {
        assert_eq!(Threads::default(), Threads::All);
    }

    #[test]
    fn threads_num_threads_all_is_zero() {
        assert_eq!(Threads::All.num_threads(), 0);
    }

    #[test]
    fn threads_num_threads_exact() {
        assert_eq!(exact(8).num_threads(), 8);
        assert_eq!(exact(1).num_threads(), 1);
    }

    #[test]
    fn threads_display() {
        assert_eq!(Threads::All.to_string(), "0");
        assert_eq!(exact(4).to_string(), "4");
    }

    #[test]
    fn threads_from_str() {
        assert_eq!("0".parse::<Threads>(), Ok(Threads::All));
        assert_eq!("4".parse::<Threads>(), Ok(exact(4)));
        assert_eq!("1".parse::<Threads>(), Ok(exact(1)));
        assert!("abc".parse::<Threads>().is_err());
    }

    #[test]
    fn threads_display_roundtrip() {
        for t in [Threads::All, exact(1), exact(8)] {
            assert_eq!(t.to_string().parse::<Threads>(), Ok(t));
        }
    }
}