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refactor: optimize username cloning for Unix processes #1816

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Merged
ClementTsang merged 7 commits into from
Sep 15, 2025
Merged

refactor: optimize username cloning for Unix processes #1816

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10792ac
refactor: rename/update comments for uid_to_username
ClementTsang Sep 14, 2025
38bb4db
use arc<str> instead of cloning user repeatedly
ClementTsang Sep 14, 2025
ba3678a
clippy
ClementTsang Sep 14, 2025
2f1ded7
oop
ClementTsang Sep 14, 2025
a47c491
oop2
ClementTsang Sep 14, 2025
5e844b7
hmmm hopefully that works?
ClementTsang Sep 15, 2025
aaa69b4
ugh
ClementTsang Sep 15, 2025
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4 changes: 2 additions & 2 deletions src/collection/processes.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ cfg_if! {
}
}

use std::{borrow::Cow, time::Duration};
use std::{sync::Arc, time::Duration};

use super::{DataCollector, error::CollectionResult};

Expand Down Expand Up @@ -128,7 +128,7 @@ pub struct ProcessHarvest {
pub uid: Option<libc::uid_t>,

/// This is the process' user.
pub user: Cow<'static, str>,
pub user: Option<Arc<str>>,

/// Gpu memory usage as bytes.
#[cfg(feature = "gpu")]
Expand Down
9 changes: 1 addition & 8 deletions src/collection/processes/linux/mod.rs
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Expand Up @@ -201,14 +201,7 @@ fn read_proc(
(0, 0, 0, 0)
};

let user = uid
.and_then(|uid| {
user_table
.get_uid_to_username_mapping(uid)
.map(Into::into)
.ok()
})
.unwrap_or_else(|| "N/A".into());
let user = uid.and_then(|uid| user_table.uid_to_username(uid).ok());

let time = if let Ok(ticks_per_sec) = u32::try_from(rustix::param::clock_ticks_per_second()) {
if ticks_per_sec == 0 {
Expand Down
9 changes: 1 addition & 8 deletions src/collection/processes/unix/process_ext.rs
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Expand Up @@ -88,14 +88,7 @@ pub(crate) trait UnixProcessExt {
total_write: disk_usage.total_written_bytes,
process_state,
uid,
user: uid
.and_then(|uid| {
user_table
.get_uid_to_username_mapping(uid)
.map(Into::into)
.ok()
})
.unwrap_or_else(|| "N/A".into()),
user: uid.and_then(|uid| user_table.uid_to_username(uid).ok()),
time: if process_val.start_time() == 0 {
// Workaround for sysinfo occasionally returning a start time equal to UNIX
// epoch, giving a run time in the range of 50+ years. We just
Expand Down
15 changes: 10 additions & 5 deletions src/collection/processes/unix/user_table.rs
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@@ -1,28 +1,33 @@
use std::sync::Arc;

use hashbrown::HashMap;

use crate::collection::error::{CollectionError, CollectionResult};

#[derive(Debug, Default)]
pub struct UserTable {
pub uid_user_mapping: HashMap<libc::uid_t, String>,
pub uid_user_mapping: HashMap<libc::uid_t, Arc<str>>,
}

impl UserTable {
pub fn get_uid_to_username_mapping(&mut self, uid: libc::uid_t) -> CollectionResult<String> {
/// Get the username associated with a UID. On first access of a name, it will
/// be cached for future accesses.
pub fn uid_to_username(&mut self, uid: libc::uid_t) -> CollectionResult<Arc<str>> {
if let Some(user) = self.uid_user_mapping.get(&uid) {
Ok(user.clone())
} else {
// SAFETY: getpwuid returns a null pointer if no passwd entry is found for the uid.
// SAFETY: getpwuid returns a null pointer if no passwd entry is found for the uid which we check.
let passwd = unsafe { libc::getpwuid(uid) };

if passwd.is_null() {
Err("passwd is inaccessible".into())
} else {
// SAFETY: We return early if passwd is null.
let username = unsafe { std::ffi::CStr::from_ptr((*passwd).pw_name) }
let username: Arc<str> = unsafe { std::ffi::CStr::from_ptr((*passwd).pw_name) }
.to_str()
.map_err(|err| CollectionError::General(err.into()))?
.to_string();
.into();

self.uid_user_mapping.insert(uid, username.clone());

Ok(username)
Expand Down
3 changes: 1 addition & 2 deletions src/collection/processes/windows.rs
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Expand Up @@ -108,8 +108,7 @@ pub fn sysinfo_process_data(
process_state,
user: process_val
.user_id()
.and_then(|uid| users.get_user_by_id(uid))
.map_or_else(|| "N/A".into(), |user| user.name().to_owned().into()),
.and_then(|uid| users.get_user_by_id(uid).map(|user| user.name().into())),
time: if process_val.start_time() == 0 {
// Workaround for sysinfo occasionally returning a start time equal to UNIX
// epoch, giving a run time in the range of 50+ years. We just
Expand Down
4 changes: 2 additions & 2 deletions src/widgets/process_table.rs
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Expand Up @@ -1188,9 +1188,9 @@ mod test {
process_state: "N/A",
process_char: '?',
#[cfg(target_family = "unix")]
user: "root".to_string(),
user: Some("root".into()),
#[cfg(not(target_family = "unix"))]
user: "N/A".to_string(),
user: Some("N/A".into()),
num_similar: 0,
disabled: false,
time: Duration::from_secs(0),
Expand Down
9 changes: 5 additions & 4 deletions src/widgets/process_table/process_columns.rs
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Expand Up @@ -151,16 +151,17 @@ impl SortsRow for ProcColumn {
}
ProcColumn::State => {
if descending {
data.sort_by_cached_key(|pd| Reverse(pd.process_state.to_lowercase()));
data.sort_by_cached_key(|pd| Reverse(pd.process_state));
} else {
data.sort_by_cached_key(|pd| pd.process_state.to_lowercase());
data.sort_by_cached_key(|pd| pd.process_state);
}
}
ProcColumn::User => {
// FIXME: Is there a better way here to keep the to_lowercase? Usually it shouldn't matter but...
if descending {
data.sort_by_cached_key(|pd| Reverse(pd.user.to_lowercase()));
data.sort_by_cached_key(|pd| Reverse(pd.user.clone()));
} else {
data.sort_by_cached_key(|pd| pd.user.to_lowercase());
data.sort_by_cached_key(|pd| pd.user.clone());
}
}
ProcColumn::Time => {
Expand Down
17 changes: 13 additions & 4 deletions src/widgets/process_table/process_data.rs
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Expand Up @@ -3,6 +3,7 @@ use std::{
cmp::{Ordering, max},
fmt::Display,
num::NonZeroU16,
sync::Arc,
time::Duration,
};

Expand Down Expand Up @@ -206,7 +207,7 @@ pub struct ProcWidgetData {
pub total_write: u64,
pub process_state: &'static str,
pub process_char: char,
pub user: String,
pub user: Option<Arc<str>>,
pub num_similar: u64,
pub disabled: bool,
pub time: Duration,
Expand Down Expand Up @@ -249,7 +250,7 @@ impl ProcWidgetData {
total_write: process.total_write,
process_state: process.process_state.0,
process_char: process.process_state.1,
user: process.user.to_string(),
user: process.user.clone(),
num_similar: 1,
disabled: false,
time: process.time,
Expand Down Expand Up @@ -318,7 +319,11 @@ impl ProcWidgetData {
ProcColumn::TotalRead => dec_bytes_string(self.total_read),
ProcColumn::TotalWrite => dec_bytes_string(self.total_write),
ProcColumn::State => self.process_char.to_string(),
ProcColumn::User => self.user.clone(),
ProcColumn::User => self
.user
.as_ref()
.map(|user| user.to_string())
.unwrap_or_else(|| "N/A".to_string()),
ProcColumn::Time => format_time(self.time),
#[cfg(feature = "gpu")]
ProcColumn::GpuMemValue | ProcColumn::GpuMemPercent => self.gpu_mem_usage.to_string(),
Expand Down Expand Up @@ -355,7 +360,11 @@ impl DataToCell<ProcColumn> for ProcWidgetData {
self.process_state.into()
}
}
ProcColumn::User => self.user.clone().into(),
ProcColumn::User => self
.user
.as_ref()
.map(|user| user.to_string().into())
.unwrap_or_else(|| "N/A".into()),
ProcColumn::Time => format_time(self.time).into(),
#[cfg(feature = "gpu")]
ProcColumn::GpuMemValue | ProcColumn::GpuMemPercent => {
Expand Down
5 changes: 4 additions & 1 deletion src/widgets/process_table/query.rs
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Expand Up @@ -815,7 +815,10 @@ impl Prefix {
}),
PrefixType::Pid => r.is_match(process.pid.to_string().as_str()),
PrefixType::State => r.is_match(process.process_state.0),
PrefixType::User => r.is_match(process.user.as_ref()),
PrefixType::User => match process.user.as_ref() {
Some(user) => r.is_match(user),
None => r.is_match("N/A"),
},
_ => true,
}
} else {
Expand Down