[PATCH 1/3] ntdll: Remove no longer used interlocked_dec_if_nonzero().
Signed-off-by: Zebediah Figura <zfigura(a)codeweavers.com> --- dlls/ntdll/sync.c | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/dlls/ntdll/sync.c b/dlls/ntdll/sync.c index edf081a9e53b..9c62f8eb6c5f 100644 --- a/dlls/ntdll/sync.c +++ b/dlls/ntdll/sync.c @@ -69,18 +69,6 @@ static const LARGE_INTEGER zero_timeout; #define TICKSPERSEC 10000000 -static inline int interlocked_dec_if_nonzero( int *dest ) -{ - int val, tmp; - for (val = *dest;; val = tmp) - { - if (!val || (tmp = interlocked_cmpxchg( dest, val - 1, val )) == val) - break; - } - return val; -} - - #ifdef __linux__ static int wait_op = 128; /*FUTEX_WAIT|FUTEX_PRIVATE_FLAG*/ -- 2.20.1
Signed-off-by: Zebediah Figura <zfigura(a)codeweavers.com> --- This was written for Shadow of the Tomb Raider, which makes heavy use of SRW locks. However, it's not particularly clear that it improves performance there. dlls/ntdll/sync.c | 310 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 303 insertions(+), 7 deletions(-) diff --git a/dlls/ntdll/sync.c b/dlls/ntdll/sync.c index 9c62f8eb6c5f..c7a96b63c3ae 100644 --- a/dlls/ntdll/sync.c +++ b/dlls/ntdll/sync.c @@ -61,7 +61,7 @@ #include "wine/debug.h" #include "ntdll_misc.h" -WINE_DEFAULT_DEBUG_CHANNEL(ntdll); +WINE_DEFAULT_DEBUG_CHANNEL(sync); HANDLE keyed_event = NULL; @@ -71,17 +71,31 @@ static const LARGE_INTEGER zero_timeout; #ifdef __linux__ -static int wait_op = 128; /*FUTEX_WAIT|FUTEX_PRIVATE_FLAG*/ -static int wake_op = 129; /*FUTEX_WAKE|FUTEX_PRIVATE_FLAG*/ +#define FUTEX_WAIT 0 +#define FUTEX_WAKE 1 +#define FUTEX_WAIT_BITSET 9 +#define FUTEX_WAKE_BITSET 10 + +static int futex_private = 128; static inline int futex_wait( const int *addr, int val, struct timespec *timeout ) { - return syscall( __NR_futex, addr, wait_op, val, timeout, 0, 0 ); + return syscall( __NR_futex, addr, FUTEX_WAIT | futex_private, val, timeout, 0, 0 ); } static inline int futex_wake( const int *addr, int val ) { - return syscall( __NR_futex, addr, wake_op, val, NULL, 0, 0 ); + return syscall( __NR_futex, addr, FUTEX_WAKE | futex_private, val, NULL, 0, 0 ); +} + +static inline int futex_wait_bitset( const int *addr, int val, struct timespec *timeout, int mask ) +{ + return syscall( __NR_futex, addr, FUTEX_WAIT_BITSET | futex_private, val, timeout, 0, mask ); +} + +static inline int futex_wake_bitset( const int *addr, int val, int mask ) +{ + return syscall( __NR_futex, addr, FUTEX_WAKE_BITSET | futex_private, val, NULL, 0, mask ); } static inline int use_futexes(void) @@ -93,8 +107,7 @@ static inline int use_futexes(void) futex_wait( &supported, 10, NULL ); if (errno == ENOSYS) { - wait_op = 0; /*FUTEX_WAIT*/ - wake_op = 1; /*FUTEX_WAKE*/ + futex_private = 0; futex_wait( &supported, 10, NULL ); } supported = (errno != ENOSYS); @@ -1642,6 +1655,266 @@ DWORD WINAPI RtlRunOnceExecuteOnce( RTL_RUN_ONCE *once, PRTL_RUN_ONCE_INIT_FN fu return RtlRunOnceComplete( once, 0, context ? *context : NULL ); } +#ifdef __linux__ + +/* Futex-based SRW lock implementation: + * + * Since we can rely on the kernel to release all threads and don't need to + * worry about NtReleaseKeyedEvent(), we can simplify the layout a bit. The + * layout looks like this: + * + * 31 - Exclusive lock bit, set if the resource is owned exclusively. + * 30-16 - Number of exclusive waiters. Unlike the fallback implementation, + * this does not include the thread owning the lock, or shared threads + * waiting on the lock. + * 15-0 - Number of shared owners. Unlike the fallback implementation, this + * does not include the number of shared threads waiting on the lock. + * Thus the state [1, x, >=1] will never occur. + */ + +#define SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT 0x80000000 +#define SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK 0x7fff0000 +#define SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_INC 0x00010000 +#define SRWLOCK_FUTEX_SHARED_OWNERS_MASK 0x0000ffff +#define SRWLOCK_FUTEX_SHARED_OWNERS_INC 0x00000001 + +/* Futex bitmasks; these are independent from the bits in the lock itself. */ +#define SRWLOCK_FUTEX_BITSET_EXCLUSIVE 1 +#define SRWLOCK_FUTEX_BITSET_SHARED 2 + +static NTSTATUS fast_try_acquire_srw_exclusive( RTL_SRWLOCK *lock ) +{ + int old, new; + NTSTATUS ret; + + if (!use_futexes()) return STATUS_NOT_IMPLEMENTED; + + do + { + old = *(int *)lock; + + if (!(old & SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT) + && !(old & SRWLOCK_FUTEX_SHARED_OWNERS_MASK)) + { + /* Not locked exclusive or shared. We can try to grab it. */ + new = old | SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT; + ret = STATUS_SUCCESS; + } + else + { + new = old; + ret = STATUS_TIMEOUT; + } + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + return ret; +} + +static NTSTATUS fast_acquire_srw_exclusive( RTL_SRWLOCK *lock ) +{ + int old, new; + BOOLEAN wait; + + if (!use_futexes()) return STATUS_NOT_IMPLEMENTED; + + /* Atomically increment the exclusive waiter count. */ + do + { + old = *(int *)lock; + new = old + SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_INC; + assert(new & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK); + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + for (;;) + { + do + { + old = *(int *)lock; + + if (!(old & SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT) + && !(old & SRWLOCK_FUTEX_SHARED_OWNERS_MASK)) + { + /* Not locked exclusive or shared. We can try to grab it. */ + new = old | SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT; + assert(old & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK); + new -= SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_INC; + wait = FALSE; + } + else + { + new = old; + wait = TRUE; + } + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + if (!wait) + return STATUS_SUCCESS; + + futex_wait_bitset( (int *)lock, new, NULL, SRWLOCK_FUTEX_BITSET_EXCLUSIVE ); + } + + return STATUS_SUCCESS; +} + +static NTSTATUS fast_try_acquire_srw_shared( RTL_SRWLOCK *lock ) +{ + int new, old; + NTSTATUS ret; + + if (!use_futexes()) return STATUS_NOT_IMPLEMENTED; + + do + { + old = *(int *)lock; + + if (!(old & SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT) + && !(old & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK)) + { + /* Not locked exclusive, and no exclusive waiters. We can try to + * grab it. */ + new = old + SRWLOCK_FUTEX_SHARED_OWNERS_INC; + assert(new & SRWLOCK_FUTEX_SHARED_OWNERS_MASK); + ret = STATUS_SUCCESS; + } + else + { + new = old; + ret = STATUS_TIMEOUT; + } + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + return ret; +} + +static NTSTATUS fast_acquire_srw_shared( RTL_SRWLOCK *lock ) +{ + int old, new; + BOOLEAN wait; + + if (!use_futexes()) return STATUS_NOT_IMPLEMENTED; + + for (;;) + { + do + { + old = *(int *)lock; + + if (!(old & SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT) + && !(old & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK)) + { + /* Not locked exclusive, and no exclusive waiters. We can try + * to grab it. */ + new = old + SRWLOCK_FUTEX_SHARED_OWNERS_INC; + assert(new & SRWLOCK_FUTEX_SHARED_OWNERS_MASK); + wait = FALSE; + } + else + { + new = old; + wait = TRUE; + } + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + if (!wait) + return STATUS_SUCCESS; + + futex_wait_bitset( (int *)lock, new, NULL, SRWLOCK_FUTEX_BITSET_SHARED ); + } + + return STATUS_SUCCESS; +} + +static NTSTATUS fast_release_srw_exclusive( RTL_SRWLOCK *lock ) +{ + int old, new; + + if (!use_futexes()) return STATUS_NOT_IMPLEMENTED; + + do + { + old = *(int *)lock; + + if (!(old & SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT)) + { + ERR("Lock %p is not owned exclusive! (%#x)\n", lock, *(int *)lock); + return STATUS_RESOURCE_NOT_OWNED; + } + + new = old & ~SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT; + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + if (new & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK) + futex_wake_bitset( (int *)lock, 1, SRWLOCK_FUTEX_BITSET_EXCLUSIVE ); + else + futex_wake_bitset( (int *)lock, INT_MAX, SRWLOCK_FUTEX_BITSET_SHARED ); + + return STATUS_SUCCESS; +} + +static NTSTATUS fast_release_srw_shared( RTL_SRWLOCK *lock ) +{ + int old, new; + + if (!use_futexes()) return STATUS_NOT_IMPLEMENTED; + + do + { + old = *(int *)lock; + + if (old & SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT) + { + ERR("Lock %p is owned exclusive! (%#x)\n", lock, *(int *)lock); + return STATUS_RESOURCE_NOT_OWNED; + } + else if (!(old & SRWLOCK_FUTEX_SHARED_OWNERS_MASK)) + { + ERR("Lock %p is not owned shared! (%#x)\n", lock, *(int *)lock); + return STATUS_RESOURCE_NOT_OWNED; + } + + new = old - SRWLOCK_FUTEX_SHARED_OWNERS_INC; + } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); + + /* Optimization: only bother waking if there are actually exclusive waiters. */ + if (!(new & SRWLOCK_FUTEX_SHARED_OWNERS_MASK) && (new & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK)) + futex_wake_bitset( (int *)lock, 1, SRWLOCK_FUTEX_BITSET_EXCLUSIVE ); + + return STATUS_SUCCESS; +} + +#else + +static NTSTATUS fast_try_acquire_srw_exclusive( RTL_SRWLOCK *lock ) +{ + return STATUS_NOT_IMPLEMENTED; +} + +static NTSTATUS fast_acquire_srw_exclusive( RTL_SRWLOCK *lock ) +{ + return STATUS_NOT_IMPLEMENTED; +} + +static NTSTATUS fast_try_acquire_srw_shared( RTL_SRWLOCK *lock ) +{ + return STATUS_NOT_IMPLEMENTED; +} + +static NTSTATUS fast_acquire_srw_shared( RTL_SRWLOCK *lock ) +{ + return STATUS_NOT_IMPLEMENTED; +} + +static NTSTATUS fast_release_srw_exclusive( RTL_SRWLOCK *lock ) +{ + return STATUS_NOT_IMPLEMENTED; +} + +static NTSTATUS fast_release_srw_shared( RTL_SRWLOCK *lock ) +{ + return STATUS_NOT_IMPLEMENTED; +} + +#endif /* SRW locks implementation * @@ -1789,6 +2062,9 @@ void WINAPI RtlInitializeSRWLock( RTL_SRWLOCK *lock ) */ void WINAPI RtlAcquireSRWLockExclusive( RTL_SRWLOCK *lock ) { + if (fast_acquire_srw_exclusive( lock ) != STATUS_NOT_IMPLEMENTED) + return; + if (srwlock_lock_exclusive( (unsigned int *)&lock->Ptr, SRWLOCK_RES_EXCLUSIVE )) NtWaitForKeyedEvent( 0, srwlock_key_exclusive(lock), FALSE, NULL ); } @@ -1803,6 +2079,10 @@ void WINAPI RtlAcquireSRWLockExclusive( RTL_SRWLOCK *lock ) void WINAPI RtlAcquireSRWLockShared( RTL_SRWLOCK *lock ) { unsigned int val, tmp; + + if (fast_acquire_srw_shared( lock ) != STATUS_NOT_IMPLEMENTED) + return; + /* Acquires a shared lock. If it's currently not possible to add elements to * the shared queue, then request exclusive access instead. */ for (val = *(unsigned int *)&lock->Ptr;; val = tmp) @@ -1833,6 +2113,9 @@ void WINAPI RtlAcquireSRWLockShared( RTL_SRWLOCK *lock ) */ void WINAPI RtlReleaseSRWLockExclusive( RTL_SRWLOCK *lock ) { + if (fast_release_srw_exclusive( lock ) != STATUS_NOT_IMPLEMENTED) + return; + srwlock_leave_exclusive( lock, srwlock_unlock_exclusive( (unsigned int *)&lock->Ptr, - SRWLOCK_RES_EXCLUSIVE ) - SRWLOCK_RES_EXCLUSIVE ); } @@ -1842,6 +2125,9 @@ void WINAPI RtlReleaseSRWLockExclusive( RTL_SRWLOCK *lock ) */ void WINAPI RtlReleaseSRWLockShared( RTL_SRWLOCK *lock ) { + if (fast_release_srw_shared( lock ) != STATUS_NOT_IMPLEMENTED) + return; + srwlock_leave_shared( lock, srwlock_lock_exclusive( (unsigned int *)&lock->Ptr, - SRWLOCK_RES_SHARED ) - SRWLOCK_RES_SHARED ); } @@ -1855,6 +2141,11 @@ void WINAPI RtlReleaseSRWLockShared( RTL_SRWLOCK *lock ) */ BOOLEAN WINAPI RtlTryAcquireSRWLockExclusive( RTL_SRWLOCK *lock ) { + NTSTATUS ret; + + if ((ret = fast_try_acquire_srw_exclusive( lock )) != STATUS_NOT_IMPLEMENTED) + return (ret == STATUS_SUCCESS); + return interlocked_cmpxchg( (int *)&lock->Ptr, SRWLOCK_MASK_IN_EXCLUSIVE | SRWLOCK_RES_EXCLUSIVE, 0 ) == 0; } @@ -1865,6 +2156,11 @@ BOOLEAN WINAPI RtlTryAcquireSRWLockExclusive( RTL_SRWLOCK *lock ) BOOLEAN WINAPI RtlTryAcquireSRWLockShared( RTL_SRWLOCK *lock ) { unsigned int val, tmp; + NTSTATUS ret; + + if ((ret = fast_try_acquire_srw_shared( lock )) != STATUS_NOT_IMPLEMENTED) + return (ret == STATUS_SUCCESS); + for (val = *(unsigned int *)&lock->Ptr;; val = tmp) { if (val & SRWLOCK_MASK_EXCLUSIVE_QUEUE) -- 2.20.1
Signed-off-by: Zebediah Figura <zfigura(a)codeweavers.com> --- This may make more sense squashed into the previous; I'm ambivalent. dlls/ntdll/sync.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/dlls/ntdll/sync.c b/dlls/ntdll/sync.c index c7a96b63c3ae..35b89df52ed7 100644 --- a/dlls/ntdll/sync.c +++ b/dlls/ntdll/sync.c @@ -1667,7 +1667,10 @@ DWORD WINAPI RtlRunOnceExecuteOnce( RTL_RUN_ONCE *once, PRTL_RUN_ONCE_INIT_FN fu * 30-16 - Number of exclusive waiters. Unlike the fallback implementation, * this does not include the thread owning the lock, or shared threads * waiting on the lock. - * 15-0 - Number of shared owners. Unlike the fallback implementation, this + * 15 - Does this lock have any shared waiters? We use this as an + * optimization to avoid unnecessary FUTEX_WAKE_BITSET calls when + * releasing an exclusive lock. + * 14-0 - Number of shared owners. Unlike the fallback implementation, this * does not include the number of shared threads waiting on the lock. * Thus the state [1, x, >=1] will never occur. */ @@ -1675,7 +1678,8 @@ DWORD WINAPI RtlRunOnceExecuteOnce( RTL_RUN_ONCE *once, PRTL_RUN_ONCE_INIT_FN fu #define SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT 0x80000000 #define SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK 0x7fff0000 #define SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_INC 0x00010000 -#define SRWLOCK_FUTEX_SHARED_OWNERS_MASK 0x0000ffff +#define SRWLOCK_FUTEX_SHARED_WAITERS_BIT 0x00008000 +#define SRWLOCK_FUTEX_SHARED_OWNERS_MASK 0x00007fff #define SRWLOCK_FUTEX_SHARED_OWNERS_INC 0x00000001 /* Futex bitmasks; these are independent from the bits in the lock itself. */ @@ -1810,7 +1814,7 @@ static NTSTATUS fast_acquire_srw_shared( RTL_SRWLOCK *lock ) } else { - new = old; + new = old | SRWLOCK_FUTEX_SHARED_WAITERS_BIT; wait = TRUE; } } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); @@ -1841,11 +1845,14 @@ static NTSTATUS fast_release_srw_exclusive( RTL_SRWLOCK *lock ) } new = old & ~SRWLOCK_FUTEX_EXCLUSIVE_LOCK_BIT; + + if (!(new & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK)) + new &= ~SRWLOCK_FUTEX_SHARED_WAITERS_BIT; } while (interlocked_cmpxchg( (int *)lock, new, old ) != old); if (new & SRWLOCK_FUTEX_EXCLUSIVE_WAITERS_MASK) futex_wake_bitset( (int *)lock, 1, SRWLOCK_FUTEX_BITSET_EXCLUSIVE ); - else + else if (old & SRWLOCK_FUTEX_SHARED_WAITERS_BIT) futex_wake_bitset( (int *)lock, INT_MAX, SRWLOCK_FUTEX_BITSET_SHARED ); return STATUS_SUCCESS; -- 2.20.1
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Zebediah Figura