/* * Copyright (C) 2004-2007, 2011, 2012 Internet Systems Consortium, Inc. ("ISC") * Copyright (C) 1999-2001 Internet Software Consortium. * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR * PERFORMANCE OF THIS SOFTWARE. */ /* $Id$ */ #ifndef ISC_TASKPOOL_H #define ISC_TASKPOOL_H 1 /***** ***** Module Info *****/ /*! \file isc/taskpool.h * \brief A task pool is a mechanism for sharing a small number of tasks * among a large number of objects such that each object is * assigned a unique task, but each task may be shared by several * objects. * * Task pools are used to let objects that can exist in large * numbers (e.g., zones) use tasks for synchronization without * the memory overhead and unfair scheduling competition that * could result from creating a separate task for each object. */ /*** *** Imports. ***/ #include <isc/lang.h> #include <isc/task.h> ISC_LANG_BEGINDECLS /***** ***** Types. *****/ typedef struct isc_taskpool isc_taskpool_t; /***** ***** Functions. *****/ isc_result_t isc_taskpool_create(isc_taskmgr_t *tmgr, isc_mem_t *mctx, unsigned int ntasks, unsigned int quantum, isc_taskpool_t **poolp); /*%< * Create a task pool of "ntasks" tasks, each with quantum * "quantum". * * Requires: * *\li 'tmgr' is a valid task manager. * *\li 'mctx' is a valid memory context. * *\li poolp != NULL && *poolp == NULL * * Ensures: * *\li On success, '*taskp' points to the new task pool. * * Returns: * *\li #ISC_R_SUCCESS *\li #ISC_R_NOMEMORY *\li #ISC_R_UNEXPECTED */ void isc_taskpool_gettask(isc_taskpool_t *pool, isc_task_t **targetp); /*%< * Attach to a task from the pool. Currently the next task is chosen * from the pool at random. (This may be changed in the future to * something that guaratees balance.) */ int isc_taskpool_size(isc_taskpool_t *pool); /*%< * Returns the number of tasks in the task pool 'pool'. */ isc_result_t isc_taskpool_expand(isc_taskpool_t **sourcep, unsigned int size, isc_taskpool_t **targetp); /*%< * If 'size' is larger than the number of tasks in the pool pointed to by * 'sourcep', then a new taskpool of size 'size' is allocated, the existing * tasks from are moved into it, additional tasks are created to bring the * total number up to 'size', and the resulting pool is attached to * 'targetp'. * * If 'size' is less than or equal to the tasks in pool 'source', then * 'sourcep' is attached to 'targetp' without any other action being taken. * * In either case, 'sourcep' is detached. * * Requires: * * \li 'sourcep' is not NULL and '*source' is not NULL * \li 'targetp' is not NULL and '*source' is NULL * * Ensures: * * \li On success, '*targetp' points to a valid task pool. * \li On success, '*sourcep' points to NULL. * * Returns: * * \li #ISC_R_SUCCESS * \li #ISC_R_NOMEMORY */ void isc_taskpool_destroy(isc_taskpool_t **poolp); /*%< * Destroy a task pool. The tasks in the pool are detached but not * shut down. * * Requires: * \li '*poolp' is a valid task pool. */ ISC_LANG_ENDDECLS #endif /* ISC_TASKPOOL_H */