region_hash_locks(5) OBSOLETE region_hash_locks(5)NAMEregion_hash_locks - OBSOLETE kernel tunable parameter
DESCRIPTION
The tunable is obsolete and has been removed. HP-UX will automatically
calculate its value based on the system configuration.
Global kernel structures containing information on a running process or
memory usage are frequently accessed or modified by several threads
concurrently. To prevent race conditions, these structures are pro‐
tected by spinlocks (kernel data structures used for synchronization)
which allow only the spinlock "holder" to proceed, while all others
attempting to access the structure must wait.
Hashed spinlocks are used when each instance of such a data structure
is to be protected, and there are several instances. Using a single
spinlock for all instances would cause too much contention, but using
one spinlock per structure wastes memory while the majority of the
locks are unused at any given time.
By allocating a pool of hashed locks, a hash function picks one lock
per group of structures, reducing contention while conserving memory.
The system-calculated value of sets the size of such a pool for the
region data structure spinlocks.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parame‐
ter may be removed or have its meaning changed in future releases of
HP-UX.
Installation of optional kernel software, from HP or other vendors, may
cause changes to tunable parameter values. After installation, some
tunable parameters may no longer be at the default or recommended val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
AUTHOR
was developed by HP.
Tunable Kernel Parameters region_hash_locks(5)