Edit File: taskpool.h
/* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #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 <stdbool.h> #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. */ void isc_taskpool_setprivilege(isc_taskpool_t *pool, bool priv); /*%< * Set the privilege flag on all tasks in 'pool' to 'priv'. If 'priv' is * true, then when the task manager is set into privileged mode, only * tasks wihin this pool will be able to execute. (Note: It is important * to turn the pool tasks' privilege back off before the last task finishes * executing.) * * Requires: * \li 'pool' is a valid task pool. */ ISC_LANG_ENDDECLS #endif /* ISC_TASKPOOL_H */
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