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Add timeout versions for LightLock, RecursiveLock, and LightSemaphore

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This commit is contained in:
Chris Feger 2023-05-02 14:15:47 -07:00
parent 8d90551306
commit a50a91c160
2 changed files with 176 additions and 8 deletions
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25
libctru/include/3ds/synchronization.h Executable file → Normal file
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@ -176,6 +176,14 @@ Result syncArbitrateAddressWithTimeout(s32* addr, ArbitrationType type, s32 valu
*/
void LightLock_Init(LightLock* lock);
/**
* @brief Attempts to lock a light lock, failing if it exceeeds a timeout.
* @param lock Pointer to the lock.
* @param timeout_ns Timeout in nanoseconds.
* @return Zero on success, non-zero on failure.
*/
int LightLock_LockTimeout(LightLock* lock, s64 timeout_ns);
/**
* @brief Locks a light lock.
* @param lock Pointer to the lock.
@ -201,6 +209,14 @@ void LightLock_Unlock(LightLock* lock);
*/
void RecursiveLock_Init(RecursiveLock* lock);
/**
* @brief Attempts to lock a recursive lock, failing if it exceeeds a timeout.
* @param lock Pointer to the lock.
* @param timeout_ns Timeout in nanoseconds.
* @return Zero on success, non-zero on failure.
*/
int RecursiveLock_LockTimeout(RecursiveLock* lock, s64 timeout_ns);
/**
* @brief Locks a recursive lock.
* @param lock Pointer to the lock.
@ -321,6 +337,15 @@ int LightEvent_WaitTimeout(LightEvent* event, s64 timeout_ns);
*/
void LightSemaphore_Init(LightSemaphore* semaphore, s16 initial_count, s16 max_count);
/**
* @brief Attempts to acquire a light semaphore, with a timeout.
* @param semaphore Pointer to the semaphore.
* @param count Acquire count
* @param timeout_ns Timeout in nanoseconds
* @return Zero on success, non-zero on failure
*/
int LightSemaphore_AcquireTimeout(LightSemaphore* semaphore, s32 count, s64 timeout_ns);
/**
* @brief Acquires a light semaphore.
* @param semaphore Pointer to the semaphore.

159
libctru/source/synchronization.c
View File

@ -1,9 +1,17 @@
#include <string.h>
#include <sys/time.h>
#include <3ds/types.h>
#include <3ds/svc.h>
#include <3ds/result.h>
#include <3ds/synchronization.h>
#define RES_IS_TIMEOUT(res) (R_DESCRIPTION(res) == RD_TIMEOUT)
static inline s64 calc_new_timeout(s64 timeout_ns, struct timespec* startTime, struct timespec* currentTime)
{
return timeout_ns - (currentTime->tv_sec - startTime->tv_sec) * 1000000000ULL - (currentTime->tv_nsec - startTime->tv_nsec);
}
static Handle arbiter;
Result __sync_init(void)
@ -82,6 +90,72 @@ void LightLock_Lock(LightLock* lock)
__dmb();
}
int LightLock_LockTimeout(LightLock* lock, s64 timeout_ns)
{
s32 val;
bool bAlreadyLocked;
// Try to lock, or if that's not possible, increment the number of waiting threads
do
{
// Read the current lock state
val = __ldrex(lock);
if (val == 0) val = 1; // 0 is an invalid state - treat it as 1 (unlocked)
bAlreadyLocked = val < 0;
// Calculate the desired next state of the lock
if (!bAlreadyLocked)
val = -val; // transition into locked state
else
--val; // increment the number of waiting threads (which has the sign reversed during locked state)
} while (__strex(lock, val));
// If the lock is held by a different thread, we need to do some timing initialization
if (bAlreadyLocked)
{
struct timespec startTime;
clock_gettime(CLOCK_MONOTONIC, &startTime);
struct timespec currentTime = startTime;
// While the lock is held by a different thread:
do
{
s64 target_ns = calc_new_timeout(timeout_ns, &startTime, &currentTime);
// Wait for the lock holder thread to wake us up
Result res = syncArbitrateAddressWithTimeout(lock, ARBITRATION_WAIT_IF_LESS_THAN, 0, target_ns);
if (RES_IS_TIMEOUT(res))
{
return 1;
}
// Try to lock again
do
{
// Read the current lock state
val = __ldrex(lock);
bAlreadyLocked = val < 0;
// Calculate the desired next state of the lock
if (!bAlreadyLocked)
val = -(val-1); // decrement the number of waiting threads *and* transition into locked state
else
{
// Since the lock is still held, we need to cancel the atomic update and wait again
__clrex();
// Get the time for the new wait as well
clock_gettime(CLOCK_MONOTONIC, &currentTime);
break;
}
} while (__strex(lock, val));
} while (bAlreadyLocked);
}
__dmb();
return 0;
}
int LightLock_TryLock(LightLock* lock)
{
s32 val;
@ -132,6 +206,21 @@ void RecursiveLock_Lock(RecursiveLock* lock)
lock->counter ++;
}
int RecursiveLock_LockTimeout(RecursiveLock* lock, s64 timeout_ns)
{
u32 tag = (u32)getThreadLocalStorage();
if (lock->thread_tag != tag)
{
if (LightLock_LockTimeout(&lock->lock, timeout_ns) != 0)
{
return 1;
}
lock->thread_tag = tag;
}
lock->counter ++;
return 0;
}
int RecursiveLock_TryLock(RecursiveLock* lock)
{
u32 tag = (u32)getThreadLocalStorage();
@ -203,7 +292,7 @@ int CondVar_WaitTimeout(CondVar* cv, LightLock* lock, s64 timeout_ns)
bool timedOut = false;
Result rc = syncArbitrateAddressWithTimeout(cv, ARBITRATION_WAIT_IF_LESS_THAN_TIMEOUT, 0, timeout_ns);
if (R_DESCRIPTION(rc) == RD_TIMEOUT)
if (RES_IS_TIMEOUT(rc))
{
timedOut = CondVar_EndWait(cv, 1);
__dmb();
@ -329,15 +418,18 @@ void LightEvent_Wait(LightEvent* event)
int LightEvent_WaitTimeout(LightEvent* event, s64 timeout_ns)
{
Result timeoutRes = 0x09401BFE;
Result res = 0;
Result res = 0;
while (res != timeoutRes)
struct timespec startTime;
clock_gettime(CLOCK_MONOTONIC, &startTime);
struct timespec currentTime = startTime;
for(;;)
{
if (event->state == CLEARED_STICKY)
{
res = syncArbitrateAddressWithTimeout(&event->state, ARBITRATION_WAIT_IF_LESS_THAN_TIMEOUT, SIGNALED_ONESHOT, timeout_ns);
return res == timeoutRes;
return RES_IS_TIMEOUT(res);
}
if (event->state != CLEARED_ONESHOT)
@ -349,10 +441,17 @@ int LightEvent_WaitTimeout(LightEvent* event, s64 timeout_ns)
return 0;
}
res = syncArbitrateAddressWithTimeout(&event->state, ARBITRATION_WAIT_IF_LESS_THAN_TIMEOUT, SIGNALED_ONESHOT, timeout_ns);
}
s64 target_ns = calc_new_timeout(timeout_ns, &startTime, &currentTime);
return res == timeoutRes;
res = syncArbitrateAddressWithTimeout(&event->state, ARBITRATION_WAIT_IF_LESS_THAN_TIMEOUT, SIGNALED_ONESHOT, target_ns);
if (RES_IS_TIMEOUT(res))
{
return 1;
}
clock_gettime(CLOCK_MONOTONIC, &currentTime);
}
}
void LightSemaphore_Init(LightSemaphore* semaphore, s16 initial_count, s16 max_count)
@ -391,6 +490,50 @@ void LightSemaphore_Acquire(LightSemaphore* semaphore, s32 count)
__dmb();
}
int LightSemaphore_AcquireTimeout(LightSemaphore* semaphore, s32 count, s64 timeout_ns)
{
s32 old_count;
s16 num_threads_acq;
struct timespec startTime;
clock_gettime(CLOCK_MONOTONIC, &startTime);
struct timespec currentTime = startTime;
do
{
for (;;)
{
old_count = __ldrex(&semaphore->current_count);
if (old_count >= count)
break;
__clrex();
do
num_threads_acq = (s16)__ldrexh((u16 *)&semaphore->num_threads_acq);
while (__strexh((u16 *)&semaphore->num_threads_acq, num_threads_acq + 1));
s64 target_ns = calc_new_timeout(timeout_ns, &startTime, &currentTime);
Result res = syncArbitrateAddressWithTimeout(&semaphore->current_count, ARBITRATION_WAIT_IF_LESS_THAN, count, target_ns);
if (RES_IS_TIMEOUT(res))
{
return 1;
}
clock_gettime(CLOCK_MONOTONIC, &currentTime);
do
num_threads_acq = (s16)__ldrexh((u16 *)&semaphore->num_threads_acq);
while (__strexh((u16 *)&semaphore->num_threads_acq, num_threads_acq - 1));
}
} while (__strex(&semaphore->current_count, old_count - count));
__dmb();
return 0;
}
int LightSemaphore_TryAcquire(LightSemaphore* semaphore, s32 count)
{
s32 old_count;