134 lines
4.2 KiB
Rust
134 lines
4.2 KiB
Rust
//! Like [`std::time::Instant`], but for memory.
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//!
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//! Measures the total size of all currently allocated objects.
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use std::fmt;
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use cfg_if::cfg_if;
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#[derive(Copy, Clone)]
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pub struct MemoryUsage {
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pub allocated: Bytes,
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}
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impl fmt::Display for MemoryUsage {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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self.allocated.fmt(f)
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}
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}
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impl std::ops::Sub for MemoryUsage {
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type Output = MemoryUsage;
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fn sub(self, rhs: MemoryUsage) -> MemoryUsage {
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MemoryUsage { allocated: self.allocated - rhs.allocated }
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}
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}
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impl MemoryUsage {
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pub fn now() -> MemoryUsage {
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cfg_if! {
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if #[cfg(all(feature = "jemalloc", not(target_env = "msvc")))] {
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jemalloc_ctl::epoch::advance().unwrap();
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MemoryUsage {
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allocated: Bytes(jemalloc_ctl::stats::allocated::read().unwrap() as isize),
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}
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} else if #[cfg(all(target_os = "linux", target_env = "gnu"))] {
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memusage_linux()
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} else if #[cfg(windows)] {
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// There doesn't seem to be an API for determining heap usage, so we try to
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// approximate that by using the Commit Charge value.
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use winapi::um::processthreadsapi::*;
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use winapi::um::psapi::*;
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use std::mem::{MaybeUninit, size_of};
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let proc = unsafe { GetCurrentProcess() };
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let mut mem_counters = MaybeUninit::uninit();
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let cb = size_of::<PROCESS_MEMORY_COUNTERS>();
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let ret = unsafe { GetProcessMemoryInfo(proc, mem_counters.as_mut_ptr(), cb as u32) };
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assert!(ret != 0);
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let usage = unsafe { mem_counters.assume_init().PagefileUsage };
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MemoryUsage { allocated: Bytes(usage as isize) }
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} else {
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MemoryUsage { allocated: Bytes(0) }
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}
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}
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}
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}
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#[cfg(all(target_os = "linux", target_env = "gnu", not(feature = "jemalloc")))]
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fn memusage_linux() -> MemoryUsage {
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// Linux/glibc has 2 APIs for allocator introspection that we can use: mallinfo and mallinfo2.
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// mallinfo uses `int` fields and cannot handle memory usage exceeding 2 GB.
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// mallinfo2 is very recent, so its presence needs to be detected at runtime.
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// Both are abysmally slow.
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use std::ffi::CStr;
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use std::sync::atomic::{AtomicUsize, Ordering};
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static MALLINFO2: AtomicUsize = AtomicUsize::new(1);
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let mut mallinfo2 = MALLINFO2.load(Ordering::Relaxed);
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if mallinfo2 == 1 {
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let cstr = CStr::from_bytes_with_nul(b"mallinfo2\0").unwrap();
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mallinfo2 = unsafe { libc::dlsym(libc::RTLD_DEFAULT, cstr.as_ptr()) } as usize;
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// NB: races don't matter here, since they'll always store the same value
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MALLINFO2.store(mallinfo2, Ordering::Relaxed);
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}
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if mallinfo2 == 0 {
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// mallinfo2 does not exist, use mallinfo.
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let alloc = unsafe { libc::mallinfo() }.uordblks as isize;
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MemoryUsage { allocated: Bytes(alloc) }
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} else {
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let mallinfo2: fn() -> libc::mallinfo2 = unsafe { std::mem::transmute(mallinfo2) };
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let alloc = mallinfo2().uordblks as isize;
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MemoryUsage { allocated: Bytes(alloc) }
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}
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}
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#[derive(Default, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
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pub struct Bytes(isize);
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impl Bytes {
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pub fn new(bytes: isize) -> Bytes {
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Bytes(bytes)
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}
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}
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impl Bytes {
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pub fn megabytes(self) -> isize {
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self.0 / 1024 / 1024
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}
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}
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impl fmt::Display for Bytes {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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let bytes = self.0;
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let mut value = bytes;
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let mut suffix = "b";
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if value.abs() > 4096 {
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value /= 1024;
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suffix = "kb";
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if value.abs() > 4096 {
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value /= 1024;
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suffix = "mb";
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}
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}
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f.pad(&format!("{value}{suffix}"))
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}
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}
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impl std::ops::AddAssign<usize> for Bytes {
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fn add_assign(&mut self, x: usize) {
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self.0 += x as isize;
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}
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}
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impl std::ops::Sub for Bytes {
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type Output = Bytes;
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fn sub(self, rhs: Bytes) -> Bytes {
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Bytes(self.0 - rhs.0)
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}
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}
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