diff options
Diffstat (limited to 'src/include/storage/proc.h')
| -rw-r--r-- | src/include/storage/proc.h | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h index e58572b0c77..47ae31d2d01 100644 --- a/src/include/storage/proc.h +++ b/src/include/storage/proc.h @@ -6,7 +6,7 @@ * * Copyright (c) 1994, Regents of the University of California * - * $Id: proc.h,v 1.18 1999/02/15 03:22:37 momjian Exp $ + * $Id: proc.h,v 1.19 1999/02/19 06:06:37 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -58,19 +58,27 @@ typedef struct proc /* + * PROC_NSEMS_PER_SET is the number of semaphores in each sys-V semaphore set + * we allocate. It must be *less than* 32 (or however many bits in an int + * on your machine), or our free-semaphores bitmap won't work. You also must + * not set it higher than your kernel's SEMMSL (max semaphores per set) + * parameter, which is often around 25. * MAX_PROC_SEMS is the maximum number of per-process semaphores (those used - * by the lock mgr) we can keep track of. PROC_NSEMS_PER_SET is the number - * of semaphores in each (sys-V) semaphore set allocated. (Be careful not - * to set it to greater 32. Otherwise, the bitmap will overflow.) + * by the lock mgr) we can keep track of. It must be a multiple of + * PROC_NSEMS_PER_SET. */ -#define MAX_PROC_SEMS 128 #define PROC_NSEMS_PER_SET 16 +#define MAX_PROC_SEMS (((MAXBACKENDS-1)/PROC_NSEMS_PER_SET+1)*PROC_NSEMS_PER_SET) typedef struct procglobal { SHMEM_OFFSET freeProcs; IPCKey currKey; int32 freeSemMap[MAX_PROC_SEMS / PROC_NSEMS_PER_SET]; + /* In each freeSemMap entry, the PROC_NSEMS_PER_SET lsbs flag whether + * individual semaphores are in use, and the next higher bit is set to + * show that the entire set is allocated. + */ } PROC_HDR; extern PROC *MyProc; |