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use super::{expect, from_str, ProcResult};
#[cfg(feature = "serde1")]
use serde::{Deserialize, Serialize};
use std::{collections::HashMap, io};
fn convert_to_kibibytes(num: u64, unit: &str) -> ProcResult<u64> {
match unit {
"B" => Ok(num),
"KiB" | "kiB" | "kB" | "KB" => Ok(num * 1024),
"MiB" | "miB" | "MB" | "mB" => Ok(num * 1024 * 1024),
"GiB" | "giB" | "GB" | "gB" => Ok(num * 1024 * 1024 * 1024),
unknown => Err(build_internal_error!(format!("Unknown unit type {}", unknown))),
}
}
/// This struct reports statistics about memory usage on the system, based on
/// the `/proc/meminfo` file.
///
/// It is used by `free(1)` to report the amount of free and used memory (both
/// physical and swap) on the system as well as the shared memory and
/// buffers used by the kernel. Each struct member is generally reported in
/// bytes, but a few are unitless values.
///
/// Except as noted below, all of the fields have been present since at least
/// Linux 2.6.0. Some fields are optional and are present only if the kernel
/// was configured with various options; those dependencies are noted in the list.
///
/// **Notes**
///
/// While the file shows kilobytes (kB; 1 kB equals 1000 B),
/// it is actually kibibytes (KiB; 1 KiB equals 1024 B).
///
/// All sizes are converted to bytes. Unitless values, like `hugepages_total` are not affected.
///
/// This imprecision in /proc/meminfo is known,
/// but is not corrected due to legacy concerns -
/// programs rely on /proc/meminfo to specify size with the "kB" string.
///
/// New fields to this struct may be added at any time (even without a major or minor semver bump).
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
#[allow(non_snake_case)]
#[non_exhaustive]
pub struct Meminfo {
/// Total usable RAM (i.e., physical RAM minus a few reserved bits and the kernel binary code).
pub mem_total: u64,
/// The sum of [LowFree](#structfield.low_free) + [HighFree](#structfield.high_free).
pub mem_free: u64,
/// An estimate of how much memory is available for starting new applications, without swapping.
///
/// (since Linux 3.14)
pub mem_available: Option<u64>,
/// Relatively temporary storage for raw disk blocks that shouldn't get tremendously large (20MB or so).
pub buffers: u64,
/// In-memory cache for files read from the disk (the page cache). Doesn't include SwapCached.
pub cached: u64,
/// Memory that once was swapped out, is swapped back in but still also is in the swap
/// file.
///
/// (If memory pressure is high, these pages don't need to be swapped out again
/// because they are already in the swap file. This saves I/O.)
pub swap_cached: u64,
/// Memory that has been used more recently and usually not reclaimed unless absolutely
/// necessary.
pub active: u64,
/// Memory which has been less recently used. It is more eligible to be reclaimed for other
/// purposes.
pub inactive: u64,
/// [To be documented.]
///
/// (since Linux 2.6.28)
pub active_anon: Option<u64>,
/// [To be documented.]
///
/// (since Linux 2.6.28)
pub inactive_anon: Option<u64>,
/// [To be documented.]
///
/// (since Linux 2.6.28)
pub active_file: Option<u64>,
/// [To be documented.]
///
/// (since Linux 2.6.28)
pub inactive_file: Option<u64>,
/// [To be documented.]
///
/// (From Linux 2.6.28 to 2.6.30, CONFIG_UNEVICTABLE_LRU was required.)
pub unevictable: Option<u64>,
/// [To be documented.]
///
/// (From Linux 2.6.28 to 2.6.30, CONFIG_UNEVICTABLE_LRU was required.)
pub mlocked: Option<u64>,
/// Total amount of highmem.
///
/// Highmem is all memory above ~860MB of physical memory. Highmem areas are for use by
/// user-space programs, or for the page cache. The kernel must use tricks to access this
/// memory, making it slower to access than lowmem.
///
/// (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
pub high_total: Option<u64>,
/// Amount of free highmem.
///
/// (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
pub high_free: Option<u64>,
/// Total amount of lowmem.
///
/// Lowmem is memory which can be used for every thing that highmem can be used for,
/// but it is also available for the kernel's use for its own data structures.
/// Among many other things, it is where everything from Slab is allocated.
/// Bad things happen when you're out of lowmem.
///
/// (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
pub low_total: Option<u64>,
/// Amount of free lowmem.
///
/// (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
pub low_free: Option<u64>,
/// [To be documented.]
///
/// (since Linux 2.6.29. CONFIG_MMU is required.)
pub mmap_copy: Option<u64>,
/// Total amount of swap space available.
pub swap_total: u64,
/// Amount of swap space that is currently unused.
pub swap_free: u64,
/// Memory which is waiting to get written back to the disk.
pub dirty: u64,
/// Memory which is actively being written back to the disk.
pub writeback: u64,
/// Non-file backed pages mapped into user-space page tables.
///
/// (since Linux 2.6.18)
pub anon_pages: Option<u64>,
/// Files which have been mapped into memory (with mmap(2)), such as libraries.
pub mapped: u64,
/// Amount of memory consumed in tmpfs(5) filesystems.
///
/// (since Linux 2.6.32)
pub shmem: Option<u64>,
/// In-kernel data structures cache.
pub slab: u64,
/// Part of Slab, that cannot be reclaimed on memory pressure.
///
/// (since Linux 2.6.19)
pub s_reclaimable: Option<u64>,
/// Part of Slab, that cannot be reclaimed on memory pressure.
///
/// (since Linux 2.6.19)
pub s_unreclaim: Option<u64>,
/// Amount of memory allocated to kernel stacks.
///
/// (since Linux 2.6.32)
pub kernel_stack: Option<u64>,
/// Amount of memory dedicated to the lowest level of page tables.
///
/// (since Linux 2.6.18)
pub page_tables: Option<u64>,
/// Amount of memory allocated for seconary page tables. This currently includes KVM mmu
/// allocations on x86 and arm64.
///
/// (since Linux 6.1)
pub secondary_page_tables: Option<u64>,
/// [To be documented.]
///
/// (CONFIG_QUICKLIST is required. Since Linux 2.6.27)
pub quicklists: Option<u64>,
/// NFS pages sent to the server, but not yet committed to stable storage.
///
/// (since Linux 2.6.18)
pub nfs_unstable: Option<u64>,
/// Memory used for block device "bounce buffers".
///
/// (since Linux 2.6.18)
pub bounce: Option<u64>,
/// Memory used by FUSE for temporary writeback buffers.
///
/// (since Linux 2.6.26)
pub writeback_tmp: Option<u64>,
/// This is the total amount of memory currently available to be allocated on the system,
/// expressed in bytes.
///
/// This limit is adhered to only if strict overcommit
/// accounting is enabled (mode 2 in /proc/sys/vm/overcommit_memory). The limit is calculated
/// according to the formula described under /proc/sys/vm/overcommit_memory. For further
/// details, see the kernel source file
/// [Documentation/vm/overcommit-accounting](https://www.kernel.org/doc/Documentation/vm/overcommit-accounting).
///
/// (since Linux 2.6.10)
pub commit_limit: Option<u64>,
/// The amount of memory presently allocated on the system.
///
/// The committed memory is a sum of all of the memory which has been allocated
/// by processes, even if it has not been "used" by them as of yet. A process which allocates 1GB of memory (using malloc(3)
/// or similar), but touches only 300MB of that memory will show up as using only 300MB of memory even if it has the address space
/// allocated for the entire 1GB.
///
/// This 1GB is memory which has been "committed" to by the VM and can be used at any time by the allocating application. With
/// strict overcommit enabled on the system (mode 2 in /proc/sys/vm/overcommit_memory), allocations which would exceed the Committed_AS
/// mitLimit will not be permitted. This is useful if one needs to guarantee that processes will not fail due to lack of memory once
/// that memory has been successfully allocated.
pub committed_as: u64,
/// Total size of vmalloc memory area.
pub vmalloc_total: u64,
/// Amount of vmalloc area which is used.
pub vmalloc_used: u64,
/// Largest contiguous block of vmalloc area which is free.
pub vmalloc_chunk: u64,
/// [To be documented.]
///
/// (CONFIG_MEMORY_FAILURE is required. Since Linux 2.6.32)
pub hardware_corrupted: Option<u64>,
/// Non-file backed huge pages mapped into user-space page tables.
///
/// (CONFIG_TRANSPARENT_HUGEPAGE is required. Since Linux 2.6.38)
pub anon_hugepages: Option<u64>,
/// Memory used by shared memory (shmem) and tmpfs(5) allocated with huge pages
///
/// (CONFIG_TRANSPARENT_HUGEPAGE is required. Since Linux 4.8)
pub shmem_hugepages: Option<u64>,
/// Shared memory mapped into user space with huge pages.
///
/// (CONFIG_TRANSPARENT_HUGEPAGE is required. Since Linux 4.8)
pub shmem_pmd_mapped: Option<u64>,
/// Total CMA (Contiguous Memory Allocator) pages.
///
/// (CONFIG_CMA is required. Since Linux 3.1)
pub cma_total: Option<u64>,
/// Free CMA (Contiguous Memory Allocator) pages.
///
/// (CONFIG_CMA is required. Since Linux 3.1)
pub cma_free: Option<u64>,
/// The size of the pool of huge pages.
///
/// CONFIG_HUGETLB_PAGE is required.)
pub hugepages_total: Option<u64>,
/// The number of huge pages in the pool that are not yet allocated.
///
/// (CONFIG_HUGETLB_PAGE is required.)
pub hugepages_free: Option<u64>,
/// This is the number of huge pages for which a commitment to allocate from the pool has been
/// made, but no allocation has yet been made.
///
/// These reserved huge pages guarantee that an application will be able to allocate a
/// huge page from the pool of huge pages at fault time.
///
/// (CONFIG_HUGETLB_PAGE is required. Since Linux 2.6.17)
pub hugepages_rsvd: Option<u64>,
/// This is the number of huge pages in the pool above the value in /proc/sys/vm/nr_hugepages.
///
/// The maximum number of surplus huge pages is controlled by /proc/sys/vm/nr_overcommit_hugepages.
///
/// (CONFIG_HUGETLB_PAGE is required. Since Linux 2.6.24)
pub hugepages_surp: Option<u64>,
/// The size of huge pages.
///
/// (CONFIG_HUGETLB_PAGE is required.)
pub hugepagesize: Option<u64>,
/// Number of bytes of RAM linearly mapped by kernel in 4kB pages. (x86.)
///
/// (since Linux 2.6.27)
pub direct_map_4k: Option<u64>,
/// Number of bytes of RAM linearly mapped by kernel in 4MB pages.
///
/// (x86 with CONFIG_X86_64 or CONFIG_X86_PAE enabled. Since Linux 2.6.27)
pub direct_map_4M: Option<u64>,
/// Number of bytes of RAM linearly mapped by kernel in 2MB pages.
///
/// (x86 with neither CONFIG_X86_64 nor CONFIG_X86_PAE enabled. Since Linux 2.6.27)
pub direct_map_2M: Option<u64>,
/// (x86 with CONFIG_X86_64 and CONFIG_X86_DIRECT_GBPAGES enabled. Since Linux 2.6.27)
pub direct_map_1G: Option<u64>,
/// needs documentation
pub hugetlb: Option<u64>,
/// Memory allocated to the per-cpu alloctor used to back per-cpu allocations.
///
/// This stat excludes the cost of metadata.
pub per_cpu: Option<u64>,
/// Kernel allocations that the kernel will attempt to reclaim under memory pressure.
///
/// Includes s_reclaimable, and other direct allocations with a shrinker.
pub k_reclaimable: Option<u64>,
/// Undocumented field
///
/// (CONFIG_TRANSPARENT_HUGEPAGE is requried. Since Linux 5.4)
pub file_pmd_mapped: Option<u64>,
/// Undocumented field
///
/// (CONFIG_TRANSPARENT_HUGEPAGE is required. Since Linux 5.4)
pub file_huge_pages: Option<u64>,
/// Memory consumed by the zswap backend (compressed size).
///
/// (CONFIG_ZSWAP is required. Since Linux 5.19)
pub z_swap: Option<u64>,
/// Amount of anonymous memory stored in zswap (original size).
///
/// (CONFIG_ZSWAP is required. Since Linux 5.19)
pub z_swapped: Option<u64>,
}
impl super::FromBufRead for Meminfo {
fn from_buf_read<R: io::BufRead>(r: R) -> ProcResult<Self> {
let mut map = HashMap::new();
for line in r.lines() {
let line = expect!(line);
if line.is_empty() {
continue;
}
let mut s = line.split_whitespace();
let field = expect!(s.next(), "no field");
let value = expect!(s.next(), "no value");
let unit = s.next(); // optional
let value = from_str!(u64, value);
let value = if let Some(unit) = unit {
convert_to_kibibytes(value, unit)?
} else {
value
};
map.insert(field[..field.len() - 1].to_string(), value);
}
// use 'remove' to move the value out of the hashmap
// if there's anything still left in the map at the end, that
// means we probably have a bug/typo, or are out-of-date
let meminfo = Meminfo {
mem_total: expect!(map.remove("MemTotal")),
mem_free: expect!(map.remove("MemFree")),
mem_available: map.remove("MemAvailable"),
buffers: expect!(map.remove("Buffers")),
cached: expect!(map.remove("Cached")),
swap_cached: expect!(map.remove("SwapCached")),
active: expect!(map.remove("Active")),
inactive: expect!(map.remove("Inactive")),
active_anon: map.remove("Active(anon)"),
inactive_anon: map.remove("Inactive(anon)"),
active_file: map.remove("Active(file)"),
inactive_file: map.remove("Inactive(file)"),
unevictable: map.remove("Unevictable"),
mlocked: map.remove("Mlocked"),
high_total: map.remove("HighTotal"),
high_free: map.remove("HighFree"),
low_total: map.remove("LowTotal"),
low_free: map.remove("LowFree"),
mmap_copy: map.remove("MmapCopy"),
swap_total: expect!(map.remove("SwapTotal")),
swap_free: expect!(map.remove("SwapFree")),
dirty: expect!(map.remove("Dirty")),
writeback: expect!(map.remove("Writeback")),
anon_pages: map.remove("AnonPages"),
mapped: expect!(map.remove("Mapped")),
shmem: map.remove("Shmem"),
slab: expect!(map.remove("Slab")),
s_reclaimable: map.remove("SReclaimable"),
s_unreclaim: map.remove("SUnreclaim"),
kernel_stack: map.remove("KernelStack"),
page_tables: map.remove("PageTables"),
secondary_page_tables: map.remove("SecPageTables"),
quicklists: map.remove("Quicklists"),
nfs_unstable: map.remove("NFS_Unstable"),
bounce: map.remove("Bounce"),
writeback_tmp: map.remove("WritebackTmp"),
commit_limit: map.remove("CommitLimit"),
committed_as: expect!(map.remove("Committed_AS")),
vmalloc_total: expect!(map.remove("VmallocTotal")),
vmalloc_used: expect!(map.remove("VmallocUsed")),
vmalloc_chunk: expect!(map.remove("VmallocChunk")),
hardware_corrupted: map.remove("HardwareCorrupted"),
anon_hugepages: map.remove("AnonHugePages"),
shmem_hugepages: map.remove("ShmemHugePages"),
shmem_pmd_mapped: map.remove("ShmemPmdMapped"),
cma_total: map.remove("CmaTotal"),
cma_free: map.remove("CmaFree"),
hugepages_total: map.remove("HugePages_Total"),
hugepages_free: map.remove("HugePages_Free"),
hugepages_rsvd: map.remove("HugePages_Rsvd"),
hugepages_surp: map.remove("HugePages_Surp"),
hugepagesize: map.remove("Hugepagesize"),
direct_map_4k: map.remove("DirectMap4k"),
direct_map_4M: map.remove("DirectMap4M"),
direct_map_2M: map.remove("DirectMap2M"),
direct_map_1G: map.remove("DirectMap1G"),
k_reclaimable: map.remove("KReclaimable"),
per_cpu: map.remove("Percpu"),
hugetlb: map.remove("Hugetlb"),
file_pmd_mapped: map.remove("FilePmdMapped"),
file_huge_pages: map.remove("FileHugePages"),
z_swap: map.remove("Zswap"),
z_swapped: map.remove("Zswapped"),
};
if cfg!(test) {
assert!(map.is_empty(), "meminfo map is not empty: {:#?}", map);
}
Ok(meminfo)
}
}