diff options
Diffstat (limited to 'db-4.8.30/mutex/mut_region.c')
| -rw-r--r-- | db-4.8.30/mutex/mut_region.c | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/db-4.8.30/mutex/mut_region.c b/db-4.8.30/mutex/mut_region.c new file mode 100644 index 0000000..e985ac2 --- /dev/null +++ b/db-4.8.30/mutex/mut_region.c @@ -0,0 +1,407 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996-2009 Oracle. All rights reserved. + * + * $Id$ + */ + +#include "db_config.h" + +#include "db_int.h" +#include "dbinc/log.h" +#include "dbinc/lock.h" +#include "dbinc/mp.h" +#include "dbinc/txn.h" + +static size_t __mutex_align_size __P((ENV *)); +static int __mutex_region_init __P((ENV *, DB_MUTEXMGR *)); +static size_t __mutex_region_size __P((ENV *)); + +/* + * __mutex_open -- + * Open a mutex region. + * + * PUBLIC: int __mutex_open __P((ENV *, int)); + */ +int +__mutex_open(env, create_ok) + ENV *env; + int create_ok; +{ + DB_ENV *dbenv; + DB_MUTEXMGR *mtxmgr; + DB_MUTEXREGION *mtxregion; + db_mutex_t mutex; + u_int32_t cpu_count; + u_int i; + int ret; + + dbenv = env->dbenv; + + /* + * Initialize the ENV handle information if not already initialized. + * + * Align mutexes on the byte boundaries specified by the application. + */ + if (dbenv->mutex_align == 0) + dbenv->mutex_align = MUTEX_ALIGN; + if (dbenv->mutex_tas_spins == 0) { + cpu_count = __os_cpu_count(); + if ((ret = __mutex_set_tas_spins(dbenv, cpu_count == 1 ? + cpu_count : cpu_count * MUTEX_SPINS_PER_PROCESSOR)) != 0) + return (ret); + } + + /* + * If the user didn't set an absolute value on the number of mutexes + * we'll need, figure it out. We're conservative in our allocation, + * we need mutexes for DB handles, group-commit queues and other things + * applications allocate at run-time. The application may have kicked + * up our count to allocate its own mutexes, add that in. + */ + if (dbenv->mutex_cnt == 0) + dbenv->mutex_cnt = + __lock_region_mutex_count(env) + + __log_region_mutex_count(env) + + __memp_region_mutex_count(env) + + __txn_region_mutex_count(env) + + dbenv->mutex_inc + 100; + + /* Create/initialize the mutex manager structure. */ + if ((ret = __os_calloc(env, 1, sizeof(DB_MUTEXMGR), &mtxmgr)) != 0) + return (ret); + + /* Join/create the mutex region. */ + mtxmgr->reginfo.env = env; + mtxmgr->reginfo.type = REGION_TYPE_MUTEX; + mtxmgr->reginfo.id = INVALID_REGION_ID; + mtxmgr->reginfo.flags = REGION_JOIN_OK; + if (create_ok) + F_SET(&mtxmgr->reginfo, REGION_CREATE_OK); + if ((ret = __env_region_attach(env, + &mtxmgr->reginfo, __mutex_region_size(env))) != 0) + goto err; + + /* If we created the region, initialize it. */ + if (F_ISSET(&mtxmgr->reginfo, REGION_CREATE)) + if ((ret = __mutex_region_init(env, mtxmgr)) != 0) + goto err; + + /* Set the local addresses. */ + mtxregion = mtxmgr->reginfo.primary = + R_ADDR(&mtxmgr->reginfo, mtxmgr->reginfo.rp->primary); + mtxmgr->mutex_array = R_ADDR(&mtxmgr->reginfo, mtxregion->mutex_off); + + env->mutex_handle = mtxmgr; + + /* Allocate initial queue of mutexes. */ + if (env->mutex_iq != NULL) { + DB_ASSERT(env, F_ISSET(&mtxmgr->reginfo, REGION_CREATE)); + for (i = 0; i < env->mutex_iq_next; ++i) { + if ((ret = __mutex_alloc_int( + env, 0, env->mutex_iq[i].alloc_id, + env->mutex_iq[i].flags, &mutex)) != 0) + goto err; + /* + * Confirm we allocated the right index, correcting + * for avoiding slot 0 (MUTEX_INVALID). + */ + DB_ASSERT(env, mutex == i + 1); + } + __os_free(env, env->mutex_iq); + env->mutex_iq = NULL; +#ifndef HAVE_ATOMIC_SUPPORT + /* If necessary allocate the atomic emulation mutexes. */ + for (i = 0; i != MAX_ATOMIC_MUTEXES; i++) + if ((ret = __mutex_alloc_int( + env, 0, MTX_ATOMIC_EMULATION, + 0, &mtxregion->mtx_atomic[i])) != 0) + return (ret); +#endif + + /* + * This is the first place we can test mutexes and we need to + * know if they're working. (They CAN fail, for example on + * SunOS, when using fcntl(2) for locking and using an + * in-memory filesystem as the database environment directory. + * But you knew that, I'm sure -- it probably wasn't worth + * mentioning.) + */ + mutex = MUTEX_INVALID; + if ((ret = + __mutex_alloc(env, MTX_MUTEX_TEST, 0, &mutex) != 0) || + (ret = __mutex_lock(env, mutex)) != 0 || + (ret = __mutex_unlock(env, mutex)) != 0 || + (ret = __mutex_trylock(env, mutex)) != 0 || + (ret = __mutex_unlock(env, mutex)) != 0 || + (ret = __mutex_free(env, &mutex)) != 0) { + __db_errx(env, + "Unable to acquire/release a mutex; check configuration"); + goto err; + } +#ifdef HAVE_SHARED_LATCHES + if ((ret = + __mutex_alloc(env, + MTX_MUTEX_TEST, DB_MUTEX_SHARED, &mutex) != 0) || + (ret = __mutex_lock(env, mutex)) != 0 || + (ret = __mutex_unlock(env, mutex)) != 0 || + (ret = __mutex_rdlock(env, mutex)) != 0 || + (ret = __mutex_rdlock(env, mutex)) != 0 || + (ret = __mutex_unlock(env, mutex)) != 0 || + (ret = __mutex_unlock(env, mutex)) != 0 || + (ret = __mutex_free(env, &mutex)) != 0) { + __db_errx(env, + "Unable to acquire/release a shared latch; check configuration"); + goto err; + } +#endif + } + return (0); + +err: env->mutex_handle = NULL; + if (mtxmgr->reginfo.addr != NULL) + (void)__env_region_detach(env, &mtxmgr->reginfo, 0); + + __os_free(env, mtxmgr); + return (ret); +} + +/* + * __mutex_region_init -- + * Initialize a mutex region in shared memory. + */ +static int +__mutex_region_init(env, mtxmgr) + ENV *env; + DB_MUTEXMGR *mtxmgr; +{ + DB_ENV *dbenv; + DB_MUTEX *mutexp; + DB_MUTEXREGION *mtxregion; + db_mutex_t i; + int ret; + void *mutex_array; + + dbenv = env->dbenv; + + COMPQUIET(mutexp, NULL); + + if ((ret = __env_alloc(&mtxmgr->reginfo, + sizeof(DB_MUTEXREGION), &mtxmgr->reginfo.primary)) != 0) { + __db_errx(env, + "Unable to allocate memory for the mutex region"); + return (ret); + } + mtxmgr->reginfo.rp->primary = + R_OFFSET(&mtxmgr->reginfo, mtxmgr->reginfo.primary); + mtxregion = mtxmgr->reginfo.primary; + memset(mtxregion, 0, sizeof(*mtxregion)); + + if ((ret = __mutex_alloc( + env, MTX_MUTEX_REGION, 0, &mtxregion->mtx_region)) != 0) + return (ret); + mtxmgr->reginfo.mtx_alloc = mtxregion->mtx_region; + + mtxregion->mutex_size = __mutex_align_size(env); + + mtxregion->stat.st_mutex_align = dbenv->mutex_align; + mtxregion->stat.st_mutex_cnt = dbenv->mutex_cnt; + mtxregion->stat.st_mutex_tas_spins = dbenv->mutex_tas_spins; + + /* + * Get a chunk of memory to be used for the mutexes themselves. Each + * piece of the memory must be properly aligned, and that alignment + * may be more restrictive than the memory alignment returned by the + * underlying allocation code. We already know how much memory each + * mutex in the array will take up, but we need to offset the first + * mutex in the array so the array begins properly aligned. + * + * The OOB mutex (MUTEX_INVALID) is 0. To make this work, we ignore + * the first allocated slot when we build the free list. We have to + * correct the count by 1 here, though, otherwise our counter will be + * off by 1. + */ + if ((ret = __env_alloc(&mtxmgr->reginfo, + mtxregion->stat.st_mutex_align + + (mtxregion->stat.st_mutex_cnt + 1) * mtxregion->mutex_size, + &mutex_array)) != 0) { + __db_errx(env, + "Unable to allocate memory for mutexes from the region"); + return (ret); + } + + mtxregion->mutex_off_alloc = R_OFFSET(&mtxmgr->reginfo, mutex_array); + mutex_array = ALIGNP_INC(mutex_array, mtxregion->stat.st_mutex_align); + mtxregion->mutex_off = R_OFFSET(&mtxmgr->reginfo, mutex_array); + mtxmgr->mutex_array = mutex_array; + + /* + * Put the mutexes on a free list and clear the allocated flag. + * + * The OOB mutex (MUTEX_INVALID) is 0, skip it. + * + * The comparison is <, not <=, because we're looking ahead one + * in each link. + */ + for (i = 1; i < mtxregion->stat.st_mutex_cnt; ++i) { + mutexp = MUTEXP_SET(mtxmgr, i); + mutexp->flags = 0; + mutexp->mutex_next_link = i + 1; + } + mutexp = MUTEXP_SET(mtxmgr, i); + mutexp->flags = 0; + mutexp->mutex_next_link = MUTEX_INVALID; + mtxregion->mutex_next = 1; + mtxregion->stat.st_mutex_free = mtxregion->stat.st_mutex_cnt; + mtxregion->stat.st_mutex_inuse = mtxregion->stat.st_mutex_inuse_max = 0; + + return (0); +} + +/* + * __mutex_env_refresh -- + * Clean up after the mutex region on a close or failed open. + * + * PUBLIC: int __mutex_env_refresh __P((ENV *)); + */ +int +__mutex_env_refresh(env) + ENV *env; +{ + DB_MUTEXMGR *mtxmgr; + DB_MUTEXREGION *mtxregion; + REGINFO *reginfo; + int ret; + + mtxmgr = env->mutex_handle; + reginfo = &mtxmgr->reginfo; + mtxregion = mtxmgr->reginfo.primary; + + /* + * If a private region, return the memory to the heap. Not needed for + * filesystem-backed or system shared memory regions, that memory isn't + * owned by any particular process. + */ + if (F_ISSET(env, ENV_PRIVATE)) { + reginfo->mtx_alloc = MUTEX_INVALID; + +#ifdef HAVE_MUTEX_SYSTEM_RESOURCES + /* + * If destroying the mutex region, return any system resources + * to the system. + */ + __mutex_resource_return(env, reginfo); +#endif + /* Discard the mutex array. */ + __env_alloc_free( + reginfo, R_ADDR(reginfo, mtxregion->mutex_off_alloc)); + } + + /* Detach from the region. */ + ret = __env_region_detach(env, reginfo, 0); + + __os_free(env, mtxmgr); + + env->mutex_handle = NULL; + + return (ret); +} + +/* + * __mutex_align_size -- + * Return how much memory each mutex will take up if an array of them + * are to be properly aligned, individually, within the array. + */ +static size_t +__mutex_align_size(env) + ENV *env; +{ + DB_ENV *dbenv; + + dbenv = env->dbenv; + + return ((size_t)DB_ALIGN(sizeof(DB_MUTEX), dbenv->mutex_align)); +} + +/* + * __mutex_region_size -- + * Return the amount of space needed for the mutex region. + */ +static size_t +__mutex_region_size(env) + ENV *env; +{ + DB_ENV *dbenv; + size_t s; + + dbenv = env->dbenv; + + s = sizeof(DB_MUTEXMGR) + 1024; + + /* We discard one mutex for the OOB slot. */ + s += __env_alloc_size( + (dbenv->mutex_cnt + 1) *__mutex_align_size(env)); + + return (s); +} + +#ifdef HAVE_MUTEX_SYSTEM_RESOURCES +/* + * __mutex_resource_return + * Return any system-allocated mutex resources to the system. + * + * PUBLIC: void __mutex_resource_return __P((ENV *, REGINFO *)); + */ +void +__mutex_resource_return(env, infop) + ENV *env; + REGINFO *infop; +{ + DB_MUTEX *mutexp; + DB_MUTEXMGR *mtxmgr, mtxmgr_st; + DB_MUTEXREGION *mtxregion; + db_mutex_t i; + void *orig_handle; + + /* + * This routine is called in two cases: when discarding the regions + * from a previous Berkeley DB run, during recovery, and two, when + * discarding regions as we shut down the database environment. + * + * Walk the list of mutexes and destroy any live ones. + * + * This is just like joining a region -- the REGINFO we're handed is + * the same as the one returned by __env_region_attach(), all we have + * to do is fill in the links. + * + * !!! + * The region may be corrupted, of course. We're safe because the + * only things we look at are things that are initialized when the + * region is created, and never modified after that. + */ + memset(&mtxmgr_st, 0, sizeof(mtxmgr_st)); + mtxmgr = &mtxmgr_st; + mtxmgr->reginfo = *infop; + mtxregion = mtxmgr->reginfo.primary = + R_ADDR(&mtxmgr->reginfo, mtxmgr->reginfo.rp->primary); + mtxmgr->mutex_array = R_ADDR(&mtxmgr->reginfo, mtxregion->mutex_off); + + /* + * This is a little strange, but the mutex_handle is what all of the + * underlying mutex routines will use to determine if they should do + * any work and to find their information. Save/restore the handle + * around the work loop. + * + * The OOB mutex (MUTEX_INVALID) is 0, skip it. + */ + orig_handle = env->mutex_handle; + env->mutex_handle = mtxmgr; + for (i = 1; i <= mtxregion->stat.st_mutex_cnt; ++i, ++mutexp) { + mutexp = MUTEXP_SET(mtxmgr, i); + if (F_ISSET(mutexp, DB_MUTEX_ALLOCATED)) + (void)__mutex_destroy(env, i); + } + env->mutex_handle = orig_handle; +} +#endif |