Revision control
Copy as Markdown
Other Tools
use std::fmt;
/// Clearing the PG_Referenced and ACCESSED/YOUNG bits
/// provides a method to measure approximately how much memory
/// a process is using. One first inspects the values in the
/// "Referenced" fields for the VMAs shown in
/// `/proc/[pid]/smaps` to get an idea of the memory footprint
/// of the process. One then clears the PG_Referenced and
/// ACCESSED/YOUNG bits and, after some measured time
/// interval, once again inspects the values in the
/// "Referenced" fields to get an idea of the change in memory
/// footprint of the process during the measured interval. If
/// one is interested only in inspecting the selected mapping
/// types, then the value 2 or 3 can be used instead of 1.
///
/// The `/proc/[pid]/clear_refs` file is present only if the
/// CONFIG_PROC_PAGE_MONITOR kernel configuration option is
/// enabled.
///
/// Only writable by the owner of the process
///
/// See `procfs::Process::clear_refs()` and `procfs::Process::pagemap()`
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum ClearRefs {
/// (since Linux 2.6.22)
///
/// Reset the PG_Referenced and ACCESSED/YOUNG bits for
/// all the pages associated with the process. (Before
/// kernel 2.6.32, writing any nonzero value to this
/// file had this effect.)
PGReferencedAll = 1,
/// (since Linux 2.6.32)
///
/// Reset the PG_Referenced and ACCESSED/YOUNG bits for
/// all anonymous pages associated with the process.
PGReferencedAnonymous = 2,
/// (since Linux 2.6.32)
///
/// Reset the PG_Referenced and ACCESSED/YOUNG bits for
/// all file-mapped pages associated with the process.
PGReferencedFile = 3,
/// (since Linux 3.11)
///
/// Clear the soft-dirty bit for all the pages
/// associated with the process. This is used (in
/// conjunction with `/proc/[pid]/pagemap`) by the check-
/// point restore system to discover which pages of a
/// process have been dirtied since the file
/// `/proc/[pid]/clear_refs` was written to.
SoftDirty = 4,
/// (since Linux 4.0)
///
/// Reset the peak resident set size ("high water
/// mark") to the process's current resident set size
/// value.
PeakRSS = 5,
}
impl fmt::Display for ClearRefs {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"{}",
match self {
ClearRefs::PGReferencedAll => 1,
ClearRefs::PGReferencedAnonymous => 2,
ClearRefs::PGReferencedFile => 3,
ClearRefs::SoftDirty => 4,
ClearRefs::PeakRSS => 5,
}
)
}
}
impl std::str::FromStr for ClearRefs {
type Err = &'static str;
fn from_str(s: &str) -> Result<Self, Self::Err> {
s.parse()
.map_err(|_| "Fail to parse clear refs value")
.and_then(|n| match n {
1 => Ok(ClearRefs::PGReferencedAll),
2 => Ok(ClearRefs::PGReferencedAnonymous),
3 => Ok(ClearRefs::PGReferencedFile),
4 => Ok(ClearRefs::SoftDirty),
5 => Ok(ClearRefs::PeakRSS),
_ => Err("Unknown clear refs value"),
})
}
}