From 4c8f51ace98818a527ff1b7fcf68c458dfb16a9f Mon Sep 17 00:00:00 2001
From: jD91mZM2 <me@krake.one>
Date: Sun, 28 Apr 2019 14:51:42 +0200
Subject: [PATCH] Avoid allocations in redox epoll
---
src/header/poll/mod.rs | 1 +
src/header/sys_epoll/mod.rs | 18 +++++++++++++++---
src/header/sys_select/mod.rs | 3 +++
src/platform/redox/epoll.rs | 29 +++++++++++++++++------------
4 files changed, 36 insertions(+), 15 deletions(-)
diff --git a/src/header/poll/mod.rs b/src/header/poll/mod.rs
index 4d6f9e41..e8d9cba6 100644
--- a/src/header/poll/mod.rs
+++ b/src/header/poll/mod.rs
@@ -54,6 +54,7 @@ pub fn poll_epoll(fds: &mut [pollfd], timeout: c_int) -> c_int {
data: epoll_data {
u64: i as u64,
},
+ ..Default::default()
};
for (p, ep) in event_map.iter() {
diff --git a/src/header/sys_epoll/mod.rs b/src/header/sys_epoll/mod.rs
index ab8e4fc0..cdde0244 100644
--- a/src/header/sys_epoll/mod.rs
+++ b/src/header/sys_epoll/mod.rs
@@ -28,12 +28,24 @@ pub union epoll_data {
pub u32: u32,
pub u64: u64,
}
+impl Default for epoll_data {
+ fn default() -> Self {
+ Self { u64: 0 }
+ }
+}
#[repr(C)]
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Default)]
+// This will match in size with syscall::Event (24 bytes on 64-bit
+// systems) on redox. The `Default` trait is here so we don't need to
+// worry about the padding when using this type.
pub struct epoll_event {
- pub events: u32,
- pub data: epoll_data,
+ pub events: u32, // 4 bytes
+ // 4 automatic alignment bytes
+ pub data: epoll_data, // 8 bytes
+
+ #[cfg(target_os = "redox")]
+ pub _pad: u64, // 8 bytes
}
#[no_mangle]
diff --git a/src/header/sys_select/mod.rs b/src/header/sys_select/mod.rs
index bf77b819..c87ad6ee 100644
--- a/src/header/sys_select/mod.rs
+++ b/src/header/sys_select/mod.rs
@@ -80,6 +80,7 @@ pub fn select_epoll(
data: epoll_data {
fd: fd,
},
+ ..Default::default()
};
if epoll_ctl(*ep, EPOLL_CTL_ADD, fd, &mut event) < 0 {
return -1;
@@ -93,6 +94,7 @@ pub fn select_epoll(
data: epoll_data {
fd: fd,
},
+ ..Default::default()
};
if epoll_ctl(*ep, EPOLL_CTL_ADD, fd, &mut event) < 0 {
return -1;
@@ -106,6 +108,7 @@ pub fn select_epoll(
data: epoll_data {
fd: fd,
},
+ ..Default::default()
};
if epoll_ctl(*ep, EPOLL_CTL_ADD, fd, &mut event) < 0 {
return -1;
diff --git a/src/platform/redox/epoll.rs b/src/platform/redox/epoll.rs
index c266e463..03e3f591 100644
--- a/src/platform/redox/epoll.rs
+++ b/src/platform/redox/epoll.rs
@@ -23,19 +23,19 @@ impl PalEpoll for Sys {
}
fn epoll_ctl(epfd: c_int, op: c_int, fd: c_int, event: *mut epoll_event) -> c_int {
- let flags = unsafe { (*event).events };
Sys::write(epfd, &Event {
id: fd as usize,
- flags: flags as usize,
- data: event as usize
+ flags: unsafe { (*event).events as usize },
+
+ // NOTE: Danger when using non 64-bit systems. If this is
+ // needed, use a box or something
+ data: unsafe { mem::transmute((*event).data) }
}) as c_int
}
fn epoll_pwait(epfd: c_int, mut events: *mut epoll_event, maxevents: c_int, timeout: c_int, _sigset: *const sigset_t) -> c_int {
// TODO: sigset
- let mut redox_events = vec![Event::default(); maxevents as usize];
-
let _timer;
if timeout != -1 {
_timer = File::open(CStr::from_bytes_with_nul(b"time:\0").unwrap(), O_RDWR);
@@ -63,20 +63,25 @@ impl PalEpoll for Sys {
}
let bytes_read = Sys::read(epfd, unsafe { slice::from_raw_parts_mut(
- redox_events.as_mut_ptr() as *mut u8,
- redox_events.len() * mem::size_of::<Event>()
+ events as *mut u8,
+ maxevents as usize
) });
if bytes_read == -1 {
return -1;
}
let read = bytes_read as usize / mem::size_of::<Event>();
- for event in &redox_events {
- if event.data == 0 {
- return EINTR;
- }
+ for i in 0..maxevents {
unsafe {
- *events = *(event.data as *mut epoll_event);
+ let event = *(events as *mut Event);
+ if event.data == 0 {
+ return EINTR;
+ }
+ *events = epoll_event {
+ events: event.flags as _,
+ data: mem::transmute(event.data),
+ ..Default::default()
+ };
events = events.add(mem::size_of::<epoll_event>());
}
}
--
GitLab