codekingpro/portable-devtools

1/*-------------------------------------------------------------------------2 *3 * dsa.h4 *	  Dynamic shared memory areas.5 *6 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group7 * Portions Copyright (c) 1994, Regents of the University of California8 *9 * IDENTIFICATION10 *	  src/include/utils/dsa.h11 *12 *-------------------------------------------------------------------------13 */14#ifndef DSA_H15#define DSA_H16 17#include "port/atomics.h"18#include "storage/dsm.h"19 20/* The opaque type used for an area. */21struct dsa_area;22typedef struct dsa_area dsa_area;23 24/*25 * If this system only uses a 32-bit value for size_t, then use the 32-bit26 * implementation of DSA.  This limits the amount of DSA that can be created27 * to something significantly less than the entire 4GB address space because28 * the DSA pointer must encode both a segment identifier and an offset, but29 * that shouldn't be a significant limitation in practice.30 *31 * If this system doesn't support atomic operations on 64-bit values, then32 * we fall back to 32-bit dsa_pointer for lack of other options.33 *34 * For testing purposes, USE_SMALL_DSA_POINTER can be defined to force the use35 * of 32-bit dsa_pointer even on systems capable of supporting a 64-bit36 * dsa_pointer.37 */38#if SIZEOF_SIZE_T == 4 || !defined(PG_HAVE_ATOMIC_U64_SUPPORT) || \39	defined(USE_SMALL_DSA_POINTER)40#define SIZEOF_DSA_POINTER 441#else42#define SIZEOF_DSA_POINTER 843#endif44 45/*46 * The type of 'relative pointers' to memory allocated by a dynamic shared47 * area.  dsa_pointer values can be shared with other processes, but must be48 * converted to backend-local pointers before they can be dereferenced.  See49 * dsa_get_address.  Also, an atomic version and appropriately sized atomic50 * operations.51 */52#if SIZEOF_DSA_POINTER == 453typedef uint32 dsa_pointer;54typedef pg_atomic_uint32 dsa_pointer_atomic;55#define dsa_pointer_atomic_init pg_atomic_init_u3256#define dsa_pointer_atomic_read pg_atomic_read_u3257#define dsa_pointer_atomic_write pg_atomic_write_u3258#define dsa_pointer_atomic_fetch_add pg_atomic_fetch_add_u3259#define dsa_pointer_atomic_compare_exchange pg_atomic_compare_exchange_u3260#define DSA_POINTER_FORMAT "%08x"61#else62typedef uint64 dsa_pointer;63typedef pg_atomic_uint64 dsa_pointer_atomic;64#define dsa_pointer_atomic_init pg_atomic_init_u6465#define dsa_pointer_atomic_read pg_atomic_read_u6466#define dsa_pointer_atomic_write pg_atomic_write_u6467#define dsa_pointer_atomic_fetch_add pg_atomic_fetch_add_u6468#define dsa_pointer_atomic_compare_exchange pg_atomic_compare_exchange_u6469#define DSA_POINTER_FORMAT "%016" INT64_MODIFIER "x"70#endif71 72/* Flags for dsa_allocate_extended. */73#define DSA_ALLOC_HUGE		0x01	/* allow huge allocation (> 1 GB) */74#define DSA_ALLOC_NO_OOM	0x02	/* no failure if out-of-memory */75#define DSA_ALLOC_ZERO		0x04	/* zero allocated memory */76 77/* A sentinel value for dsa_pointer used to indicate failure to allocate. */78#define InvalidDsaPointer ((dsa_pointer) 0)79 80/* Check if a dsa_pointer value is valid. */81#define DsaPointerIsValid(x) ((x) != InvalidDsaPointer)82 83/* Allocate uninitialized memory with error on out-of-memory. */84#define dsa_allocate(area, size) \85	dsa_allocate_extended(area, size, 0)86 87/* Allocate zero-initialized memory with error on out-of-memory. */88#define dsa_allocate0(area, size) \89	dsa_allocate_extended(area, size, DSA_ALLOC_ZERO)90 91/*92 * The type used for dsa_area handles.  dsa_handle values can be shared with93 * other processes, so that they can attach to them.  This provides a way to94 * share allocated storage with other processes.95 *96 * The handle for a dsa_area is currently implemented as the dsm_handle97 * for the first DSM segment backing this dynamic storage area, but client98 * code shouldn't assume that is true.99 */100typedef dsm_handle dsa_handle;101 102/* Sentinel value to use for invalid dsa_handles. */103#define DSA_HANDLE_INVALID ((dsa_handle) DSM_HANDLE_INVALID)104 105 106extern dsa_area *dsa_create(int tranche_id);107extern dsa_area *dsa_create_in_place(void *place, size_t size,108									 int tranche_id, dsm_segment *segment);109extern dsa_area *dsa_attach(dsa_handle handle);110extern dsa_area *dsa_attach_in_place(void *place, dsm_segment *segment);111extern void dsa_release_in_place(void *place);112extern void dsa_on_dsm_detach_release_in_place(dsm_segment *, Datum);113extern void dsa_on_shmem_exit_release_in_place(int, Datum);114extern void dsa_pin_mapping(dsa_area *area);115extern void dsa_detach(dsa_area *area);116extern void dsa_pin(dsa_area *area);117extern void dsa_unpin(dsa_area *area);118extern void dsa_set_size_limit(dsa_area *area, size_t limit);119extern size_t dsa_minimum_size(void);120extern dsa_handle dsa_get_handle(dsa_area *area);121extern dsa_pointer dsa_allocate_extended(dsa_area *area, size_t size, int flags);122extern void dsa_free(dsa_area *area, dsa_pointer dp);123extern void *dsa_get_address(dsa_area *area, dsa_pointer dp);124extern void dsa_trim(dsa_area *area);125extern void dsa_dump(dsa_area *area);126 127#endif							/* DSA_H */128