#[inline]
pub unsafe fn wait(&self, mutex: &Mutex) {
- let r = ffi::SleepConditionVariableCS(self.inner.get(),
- mutex::raw(mutex),
- libc::INFINITE);
+ let r = ffi::SleepConditionVariableSRW(self.inner.get(),
+ mutex::raw(mutex),
+ libc::INFINITE,
+ 0);
debug_assert!(r != 0);
}
pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
- let r = ffi::SleepConditionVariableCS(self.inner.get(),
- mutex::raw(mutex),
- dur.num_milliseconds() as DWORD);
+ let r = ffi::SleepConditionVariableSRW(self.inner.get(),
+ mutex::raw(mutex),
+ dur.num_milliseconds() as DWORD,
+ 0);
if r == 0 {
const ERROR_TIMEOUT: DWORD = 0x5B4;
debug_assert_eq!(os::errno() as uint, ERROR_TIMEOUT as uint);
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use prelude::v1::*;
-
-use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
-use alloc::{self, heap};
-
-use libc::DWORD;
+use marker::Sync;
+use cell::UnsafeCell;
use sys::sync as ffi;
-const SPIN_COUNT: DWORD = 4000;
+pub struct Mutex { inner: UnsafeCell<ffi::SRWLOCK> }
-pub struct Mutex { inner: AtomicUsize }
-
-pub const MUTEX_INIT: Mutex = Mutex { inner: ATOMIC_USIZE_INIT };
+pub const MUTEX_INIT: Mutex = Mutex {
+ inner: UnsafeCell { value: ffi::SRWLOCK_INIT }
+};
unsafe impl Sync for Mutex {}
#[inline]
-pub unsafe fn raw(m: &Mutex) -> ffi::LPCRITICAL_SECTION {
- m.get()
+pub unsafe fn raw(m: &Mutex) -> ffi::PSRWLOCK {
+ m.inner.get()
}
+// So you might be asking why we're using SRWLock instead of CriticalSection?
+//
+// 1. SRWLock is several times faster than CriticalSection according to benchmarks performed on both
+// Windows 8 and Windows 7.
+//
+// 2. CriticalSection allows recursive locking while SRWLock deadlocks. The Unix implementation
+// deadlocks so consistency is preferred. See #19962 for more details.
+//
+// 3. While CriticalSection is fair and SRWLock is not, the current Rust policy is there there are
+// no guarantees of fairness.
+
impl Mutex {
#[inline]
- pub unsafe fn new() -> Mutex {
- Mutex { inner: AtomicUsize::new(init_lock() as uint) }
- }
+ pub unsafe fn new() -> Mutex { MUTEX_INIT }
#[inline]
pub unsafe fn lock(&self) {
- ffi::EnterCriticalSection(self.get())
+ ffi::AcquireSRWLockExclusive(self.inner.get())
}
#[inline]
pub unsafe fn try_lock(&self) -> bool {
- ffi::TryEnterCriticalSection(self.get()) != 0
+ ffi::TryAcquireSRWLockExclusive(self.inner.get()) != 0
}
#[inline]
pub unsafe fn unlock(&self) {
- ffi::LeaveCriticalSection(self.get())
+ ffi::ReleaseSRWLockExclusive(self.inner.get())
}
+ #[inline]
pub unsafe fn destroy(&self) {
- let lock = self.inner.swap(0, Ordering::SeqCst);
- if lock != 0 { free_lock(lock as ffi::LPCRITICAL_SECTION) }
- }
-
- unsafe fn get(&self) -> ffi::LPCRITICAL_SECTION {
- match self.inner.load(Ordering::SeqCst) {
- 0 => {}
- n => return n as ffi::LPCRITICAL_SECTION
- }
- let lock = init_lock();
- match self.inner.compare_and_swap(0, lock as uint, Ordering::SeqCst) {
- 0 => return lock as ffi::LPCRITICAL_SECTION,
- _ => {}
- }
- free_lock(lock);
- return self.inner.load(Ordering::SeqCst) as ffi::LPCRITICAL_SECTION;
+ // ...
}
}
-
-unsafe fn init_lock() -> ffi::LPCRITICAL_SECTION {
- let block = heap::allocate(ffi::CRITICAL_SECTION_SIZE, 8)
- as ffi::LPCRITICAL_SECTION;
- if block.is_null() { alloc::oom() }
- ffi::InitializeCriticalSectionAndSpinCount(block, SPIN_COUNT);
- return block;
-}
-
-unsafe fn free_lock(h: ffi::LPCRITICAL_SECTION) {
- ffi::DeleteCriticalSection(h);
- heap::deallocate(h as *mut _, ffi::CRITICAL_SECTION_SIZE, 8);
-}
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use libc::{BOOL, DWORD, c_void, LPVOID};
+use libc::{BOOL, DWORD, c_void, LPVOID, c_ulong};
use libc::types::os::arch::extra::BOOLEAN;
-pub type LPCRITICAL_SECTION = *mut c_void;
-pub type LPCONDITION_VARIABLE = *mut CONDITION_VARIABLE;
-pub type LPSRWLOCK = *mut SRWLOCK;
-
-#[cfg(target_arch = "x86")]
-pub const CRITICAL_SECTION_SIZE: uint = 24;
-#[cfg(target_arch = "x86_64")]
-pub const CRITICAL_SECTION_SIZE: uint = 40;
+pub type PCONDITION_VARIABLE = *mut CONDITION_VARIABLE;
+pub type PSRWLOCK = *mut SRWLOCK;
+pub type ULONG = c_ulong;
#[repr(C)]
pub struct CONDITION_VARIABLE { pub ptr: LPVOID }
pub const SRWLOCK_INIT: SRWLOCK = SRWLOCK { ptr: 0 as *mut _ };
extern "system" {
- // critical sections
- pub fn InitializeCriticalSectionAndSpinCount(
- lpCriticalSection: LPCRITICAL_SECTION,
- dwSpinCount: DWORD) -> BOOL;
- pub fn DeleteCriticalSection(lpCriticalSection: LPCRITICAL_SECTION);
- pub fn EnterCriticalSection(lpCriticalSection: LPCRITICAL_SECTION);
- pub fn LeaveCriticalSection(lpCriticalSection: LPCRITICAL_SECTION);
- pub fn TryEnterCriticalSection(lpCriticalSection: LPCRITICAL_SECTION) -> BOOL;
-
// condition variables
- pub fn SleepConditionVariableCS(ConditionVariable: LPCONDITION_VARIABLE,
- CriticalSection: LPCRITICAL_SECTION,
- dwMilliseconds: DWORD) -> BOOL;
- pub fn WakeConditionVariable(ConditionVariable: LPCONDITION_VARIABLE);
- pub fn WakeAllConditionVariable(ConditionVariable: LPCONDITION_VARIABLE);
+ pub fn SleepConditionVariableSRW(ConditionVariable: PCONDITION_VARIABLE,
+ SRWLock: PSRWLOCK,
+ dwMilliseconds: DWORD,
+ Flags: ULONG) -> BOOL;
+ pub fn WakeConditionVariable(ConditionVariable: PCONDITION_VARIABLE);
+ pub fn WakeAllConditionVariable(ConditionVariable: PCONDITION_VARIABLE);
// slim rwlocks
- pub fn AcquireSRWLockExclusive(SRWLock: LPSRWLOCK);
- pub fn AcquireSRWLockShared(SRWLock: LPSRWLOCK);
- pub fn ReleaseSRWLockExclusive(SRWLock: LPSRWLOCK);
- pub fn ReleaseSRWLockShared(SRWLock: LPSRWLOCK);
- pub fn TryAcquireSRWLockExclusive(SRWLock: LPSRWLOCK) -> BOOLEAN;
- pub fn TryAcquireSRWLockShared(SRWLock: LPSRWLOCK) -> BOOLEAN;
+ pub fn AcquireSRWLockExclusive(SRWLock: PSRWLOCK);
+ pub fn AcquireSRWLockShared(SRWLock: PSRWLOCK);
+ pub fn ReleaseSRWLockExclusive(SRWLock: PSRWLOCK);
+ pub fn ReleaseSRWLockShared(SRWLock: PSRWLOCK);
+ pub fn TryAcquireSRWLockExclusive(SRWLock: PSRWLOCK) -> BOOLEAN;
+ pub fn TryAcquireSRWLockShared(SRWLock: PSRWLOCK) -> BOOLEAN;
}
-
projects / rust.git / commitdiff