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kernel: Improve rw_spinlock implementation

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* Add more debug checks
 * Reduce the number of executed instructions that lock the bus.
This commit is contained in:
Pawel Dziepak
2013-11-21 02:25:03 +01:00
parent 6fb61d001a
commit 024541a4c8
2 changed files with 79 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
headers/private/kernel/smp.h
+3 -2
View File
@@ -100,8 +100,6 @@ release_spinlock_inline(spinlock* lock)
#define acquire_spinlock(lock) acquire_spinlock_inline(lock)
#define release_spinlock(lock) release_spinlock_inline(lock)
#endif // !DEBUG_SPINLOCKS && !B_DEBUG_SPINLOCK_CONTENTION
static inline bool
try_acquire_write_spinlock_inline(rw_spinlock* lock)
@@ -207,4 +205,7 @@ release_read_seqlock_inline(seqlock* lock, uint32 count) {
release_read_seqlock_inline(lock, count)
#endif // !DEBUG_SPINLOCKS && !B_DEBUG_SPINLOCK_CONTENTION
#endif /* KERNEL_SMP_H */
src/system/kernel/smp.cpp
+76 -22
View File
@@ -350,7 +350,7 @@ acquire_spinlock(spinlock* lock)
#else
while (1) {
uint32 count = 0;
while (*lock != 0) {
while (atomic_get(lock) != 0) {
if (++count == SPINLOCK_DEADLOCK_COUNT) {
panic("acquire_spinlock(): Failed to acquire spinlock %p "
"for a long time!", lock);
@@ -404,7 +404,7 @@ acquire_spinlock_nocheck(spinlock *lock)
#else
while (1) {
uint32 count = 0;
while (*lock != 0) {
while (atomic_get(lock) != 0) {
if (++count == SPINLOCK_DEADLOCK_COUNT_NO_CHECK) {
panic("acquire_spinlock(): Failed to acquire spinlock %p "
"for a long time!", lock);
@@ -447,7 +447,7 @@ acquire_spinlock_cpu(int32 currentCPU, spinlock *lock)
#else
while (1) {
uint32 count = 0;
while (*lock != 0) {
while (atomic_get(lock) != 0) {
if (++count == SPINLOCK_DEADLOCK_COUNT) {
panic("acquire_spinlock_cpu(): Failed to acquire spinlock "
"%p for a long time!", lock);
@@ -530,15 +530,31 @@ release_spinlock(spinlock *lock)
bool
try_acquire_write_spinlock(rw_spinlock* lock)
{
return atomic_test_and_set(&lock->lock, 1 << 31, 0) == 0;
#if DEBUG_SPINLOCKS
if (are_interrupts_enabled()) {
panic("try_acquire_write_spinlock: attempt to acquire lock %p with"
" interrupts enabled", lock);
}
if (sNumCPUs < 2 && lock->lock != 0) {
panic("acquire_spinlock_cpu(): attempt to acquire lock %p twice on "
"non-SMP system", lock);
}
#endif
return atomic_test_and_set(&lock->lock, 1u << 31, 0) == 0;
}
void
acquire_write_spinlock(rw_spinlock* lock)
{
if (sNumCPUs < 2)
return;
#if DEBUG_SPINLOCKS
if (are_interrupts_enabled()) {
panic("acquire_write_spinlock: attempt to acquire lock %p with"
" interrupts enabled", lock);
}
#endif
uint32 count = 0;
int currentCPU = smp_get_current_cpu();
@@ -546,14 +562,16 @@ acquire_write_spinlock(rw_spinlock* lock)
if (try_acquire_write_spinlock(lock))
break;
if (++count == SPINLOCK_DEADLOCK_COUNT) {
panic("acquire_write_spinlock(): Failed to acquire spinlock %p "
"for a long time!", lock);
count = 0;
}
while (atomic_get(&lock->lock) != 0) {
if (++count == SPINLOCK_DEADLOCK_COUNT) {
panic("acquire_write_spinlock(): Failed to acquire spinlock %p "
"for a long time!", lock);
count = 0;
}
process_all_pending_ici(currentCPU);
PAUSE();
process_all_pending_ici(currentCPU);
PAUSE();
}
}
}
@@ -561,16 +579,37 @@ acquire_write_spinlock(rw_spinlock* lock)
void
release_write_spinlock(rw_spinlock* lock)
{
#if DEBUG_SPINLOCKS
uint32 previous = atomic_get_and_set(&lock->lock, 0);
if ((previous & 1u << 31) == 0) {
panic("release_write_spinlock: lock %p was already released (value:"
" %x)\n", lock, previous);
}
#else
atomic_set(&lock->lock, 0);
#endif
}
bool
try_acquire_read_spinlock(rw_spinlock* lock)
{
#if DEBUG_SPINLOCKS
if (are_interrupts_enabled()) {
panic("try_acquire_read_spinlock: attempt to acquire lock %p with"
" interrupts enabled", lock);
}
if (sNumCPUs < 2 && lock->lock != 0) {
panic("acquire_spinlock_cpu(): attempt to acquire lock %p twice on "
"non-SMP system", lock);
}
#endif
uint32 previous = atomic_add(&lock->lock, 1);
if ((previous & (1 << 31)) == 0)
return true;
atomic_test_and_set(&lock->lock, 1 << 31, previous);
return false;
}
@@ -579,8 +618,12 @@ try_acquire_read_spinlock(rw_spinlock* lock)
void
acquire_read_spinlock(rw_spinlock* lock)
{
if (sNumCPUs < 2)
return;
#if DEBUG_SPINLOCKS
if (are_interrupts_enabled()) {
panic("acquire_read_spinlock: attempt to acquire lock %p with"
" interrupts enabled", lock);
}
#endif
uint32 count = 0;
int currentCPU = smp_get_current_cpu();
@@ -588,14 +631,16 @@ acquire_read_spinlock(rw_spinlock* lock)
if (try_acquire_read_spinlock(lock))
break;
if (++count == SPINLOCK_DEADLOCK_COUNT) {
panic("acquire_read_spinlock(): Failed to acquire spinlock %p "
"for a long time!", lock);
count = 0;
}
while (atomic_get(&lock->lock) != 0) {
if (++count == SPINLOCK_DEADLOCK_COUNT) {
panic("acquire_read_spinlock(): Failed to acquire spinlock %p "
"for a long time!", lock);
count = 0;
}
process_all_pending_ici(currentCPU);
PAUSE();
process_all_pending_ici(currentCPU);
PAUSE();
}
}
}
@@ -603,7 +648,16 @@ acquire_read_spinlock(rw_spinlock* lock)
void
release_read_spinlock(rw_spinlock* lock)
{
#if DEBUG_SPINLOCKS
uint32 previous = atomic_add(&lock->lock, -1);
if ((previous & 1 << 31) != 0) {
panic("release_read_spinlock: lock %p was already released (value:"
" %x)\n", lock, previous);
}
#else
atomic_add(&lock->lock, -1);
#endif
}