1 /*------------------------------------------------------------------------- 2 * 3 * dsm.h 4 * manage dynamic shared memory segments 5 * 6 * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group 7 * Portions Copyright (c) 1994, Regents of the University of California 8 * 9 * src/include/storage/dsm.h 10 * 11 *------------------------------------------------------------------------- 12 */ 13 #ifndef DSM_H 14 #define DSM_H 15 16 #include "storage/dsm_impl.h" 17 18 typedef struct dsm_segment dsm_segment; 19 20 #define DSM_CREATE_NULL_IF_MAXSEGMENTS 0x0001 21 22 /* A sentinel value for an invalid DSM handle. */ 23 #define DSM_HANDLE_INVALID 0 24 25 /* Startup and shutdown functions. */ 26 struct PGShmemHeader; /* avoid including pg_shmem.h */ 27 extern void dsm_cleanup_using_control_segment(dsm_handle old_control_handle); 28 extern void dsm_postmaster_startup(struct PGShmemHeader *); 29 extern void dsm_backend_shutdown(void); 30 extern void dsm_detach_all(void); 31 32 #ifdef EXEC_BACKEND 33 extern void dsm_set_control_handle(dsm_handle h); 34 #endif 35 36 /* Functions that create, update, or remove mappings. */ 37 extern dsm_segment *dsm_create(Size size, int flags); 38 extern dsm_segment *dsm_attach(dsm_handle h); 39 extern void *dsm_resize(dsm_segment *seg, Size size); 40 extern void *dsm_remap(dsm_segment *seg); 41 extern void dsm_detach(dsm_segment *seg); 42 43 /* Resource management functions. */ 44 extern void dsm_pin_mapping(dsm_segment *seg); 45 extern void dsm_unpin_mapping(dsm_segment *seg); 46 extern void dsm_pin_segment(dsm_segment *seg); 47 extern void dsm_unpin_segment(dsm_handle h); 48 extern dsm_segment *dsm_find_mapping(dsm_handle h); 49 50 /* Informational functions. */ 51 extern void *dsm_segment_address(dsm_segment *seg); 52 extern Size dsm_segment_map_length(dsm_segment *seg); 53 extern dsm_handle dsm_segment_handle(dsm_segment *seg); 54 55 /* Cleanup hooks. */ 56 typedef void (*on_dsm_detach_callback) (dsm_segment *, Datum arg); 57 extern void on_dsm_detach(dsm_segment *seg, 58 on_dsm_detach_callback function, Datum arg); 59 extern void cancel_on_dsm_detach(dsm_segment *seg, 60 on_dsm_detach_callback function, Datum arg); 61 extern void reset_on_dsm_detach(void); 62 63 #endif /* DSM_H */ 64