1/***************************************************************************** 2 3Copyright (c) 1995, 2019, Oracle and/or its affiliates. All Rights Reserved. 4 5This program is free software; you can redistribute it and/or modify it under 6the terms of the GNU General Public License, version 2.0, as published by the 7Free Software Foundation. 8 9This program is also distributed with certain software (including but not 10limited to OpenSSL) that is licensed under separate terms, as designated in a 11particular file or component or in included license documentation. The authors 12of MySQL hereby grant you an additional permission to link the program and 13your derivative works with the separately licensed software that they have 14included with MySQL. 15 16This program is distributed in the hope that it will be useful, but WITHOUT 17ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 18FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0, 19for more details. 20 21You should have received a copy of the GNU General Public License along with 22this program; if not, write to the Free Software Foundation, Inc., 2351 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 24 25*****************************************************************************/ 26 27/** @file include/sync0arr.ic 28 The wait array for synchronization primitives 29 30 Inline code 31 32 Created 9/5/1995 Heikki Tuuri 33 *******************************************************/ 34 35extern ulint sync_array_size; 36extern sync_array_t **sync_wait_array; 37 38#include "ut0counter.h" 39 40/** Get an instance of the sync wait array. 41 @return an instance of the sync wait array. */ 42 43UNIV_INLINE 44sync_array_t *sync_array_get() { 45 if (sync_array_size <= 1) { 46 return (sync_wait_array[0]); 47 } 48 49 return ( 50 sync_wait_array[default_indexer_t<>::get_rnd_index() % sync_array_size]); 51} 52 53/** Get an instance of the sync wait array and reserve a wait array cell 54 in the instance for waiting for an object. The event of the cell is 55 reset to nonsignalled state. 56 If reserving cell of the instance fails, try to get another new 57 instance until we can reserve an empty cell of it. 58 @return the sync array reserved, never NULL. */ 59UNIV_INLINE 60sync_array_t *sync_array_get_and_reserve_cell( 61 void *object, /*!< in: pointer to the object to wait for */ 62 ulint type, /*!< in: lock request type */ 63 const char *file, /*!< in: file where requested */ 64 ulint line, /*!< in: line where requested */ 65 sync_cell_t **cell) /*!< out: the cell reserved, never NULL */ 66{ 67 sync_array_t *sync_arr = nullptr; 68 69 *cell = nullptr; 70 for (ulint i = 0; i < sync_array_size && *cell == nullptr; ++i) { 71 /* Although the sync_array is get in a random way currently, 72 we still try at most sync_array_size times, in case any 73 of the sync_array we get is full */ 74 sync_arr = sync_array_get(); 75 *cell = sync_array_reserve_cell(sync_arr, object, type, file, line); 76 } 77 78 /* This won't be true every time, for the loop above may execute 79 more than srv_sync_array_size times to reserve a cell. 80 But an assertion here makes the code more solid. */ 81 ut_a(*cell != nullptr); 82 83 return (sync_arr); 84} 85