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Diffstat (limited to 'lib/isc/include/isc/taskpool.h')
-rw-r--r-- | lib/isc/include/isc/taskpool.h | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/lib/isc/include/isc/taskpool.h b/lib/isc/include/isc/taskpool.h new file mode 100644 index 0000000..46f395e --- /dev/null +++ b/lib/isc/include/isc/taskpool.h @@ -0,0 +1,157 @@ +/* + * 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. + */ + +void +isc_taskpool_setprivilege(isc_taskpool_t *pool, isc_boolean_t 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 */ |