diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/storage/lmgr/lwlock.c | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c index 79cc48b23c4..8adf2730277 100644 --- a/src/backend/storage/lmgr/lwlock.c +++ b/src/backend/storage/lmgr/lwlock.c @@ -91,19 +91,29 @@ #endif -#define LW_FLAG_HAS_WAITERS ((uint32) 1 << 30) -#define LW_FLAG_RELEASE_OK ((uint32) 1 << 29) -#define LW_FLAG_LOCKED ((uint32) 1 << 28) - -#define LW_VAL_EXCLUSIVE ((uint32) 1 << 24) +#define LW_FLAG_HAS_WAITERS ((uint32) 1 << 31) +#define LW_FLAG_RELEASE_OK ((uint32) 1 << 30) +#define LW_FLAG_LOCKED ((uint32) 1 << 29) +#define LW_FLAG_BITS 3 +#define LW_FLAG_MASK (((1<<LW_FLAG_BITS)-1)<<(32-LW_FLAG_BITS)) + +/* assumes MAX_BACKENDS is a (power of 2) - 1, checked below */ +#define LW_VAL_EXCLUSIVE (MAX_BACKENDS + 1) #define LW_VAL_SHARED 1 -#define LW_LOCK_MASK ((uint32) ((1 << 25)-1)) -/* Must be greater than MAX_BACKENDS - which is 2^23-1, so we're fine. */ -#define LW_SHARED_MASK ((uint32) ((1 << 24)-1)) +/* already (power of 2)-1, i.e. suitable for a mask */ +#define LW_SHARED_MASK MAX_BACKENDS +#define LW_LOCK_MASK (MAX_BACKENDS | LW_VAL_EXCLUSIVE) + + +StaticAssertDecl(((MAX_BACKENDS + 1) & MAX_BACKENDS) == 0, + "MAX_BACKENDS + 1 needs to be a power of 2"); + +StaticAssertDecl((MAX_BACKENDS & LW_FLAG_MASK) == 0, + "MAX_BACKENDS and LW_FLAG_MASK overlap"); -StaticAssertDecl(LW_VAL_EXCLUSIVE > (uint32) MAX_BACKENDS, - "MAX_BACKENDS too big for lwlock.c"); +StaticAssertDecl((LW_VAL_EXCLUSIVE & LW_FLAG_MASK) == 0, + "LW_VAL_EXCLUSIVE and LW_FLAG_MASK overlap"); /* * There are three sorts of LWLock "tranches": |