diff options
Diffstat (limited to 'db2/lock/lock.c')
| -rw-r--r-- | db2/lock/lock.c | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/db2/lock/lock.c b/db2/lock/lock.c index 8fc91334a7..a2a3b208f2 100644 --- a/db2/lock/lock.c +++ b/db2/lock/lock.c @@ -8,7 +8,7 @@ #include "config.h" #ifndef lint -static const char sccsid[] = "@(#)lock.c 10.31 (Sleepycat) 8/17/97"; +static const char sccsid[] = "@(#)lock.c 10.36 (Sleepycat) 9/24/97"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES @@ -201,7 +201,7 @@ lock_open(path, flags, mode, dbenv, ltp) * Create the lock table structure. */ if ((lt = (DB_LOCKTAB *)calloc(1, sizeof(DB_LOCKTAB))) == NULL) { - __db_err(dbenv, "%s", strerror(errno)); + __db_err(dbenv, "%s", strerror(ENOMEM)); return (ENOMEM); } lt->dbenv = dbenv; @@ -319,8 +319,10 @@ lock_vec(lt, locker, flags, list, nlist, elistp) case DB_LOCK_GET: ret = __lock_get_internal(lt, locker, flags, list[i].obj, list[i].mode, &lp); - if (ret == 0) + if (ret == 0) { list[i].lock = LOCK_TO_OFFSET(lt, lp); + lt->region->nrequests++; + } break; case DB_LOCK_PUT: lp = OFFSET_TO_LOCK(lt, list[i].lock); @@ -351,7 +353,7 @@ lock_vec(lt, locker, flags, list, nlist, elistp) case DB_LOCK_PUT_OBJ: /* Look up the object in the hash table. */ - __db_hashlookup(lt->hashtab, __db_lockobj, links, + HASHLOOKUP(lt->hashtab, __db_lockobj, links, list[i].obj, sh_obj, lt->region->table_size, __lock_ohash, __lock_cmp); if (sh_obj == NULL) { @@ -596,8 +598,8 @@ __lock_put_internal(lt, lockp, do_all) /* Check if object should be reclaimed. */ if (SH_TAILQ_FIRST(&sh_obj->holders, __db_lock) == NULL) { - __db_hashremove_el(lt->hashtab, __db_lockobj, links, sh_obj, - lt->region->table_size, __lock_lhash); + HASHREMOVE_EL(lt->hashtab, __db_lockobj, + links, sh_obj, lt->region->table_size, __lock_lhash); __db_shalloc_free(lt->mem, SH_DBT_PTR(&sh_obj->lockobj)); SH_TAILQ_INSERT_HEAD(<->region->free_objs, sh_obj, links, __db_lockobj); @@ -676,8 +678,12 @@ __lock_get_internal(lt, locker, flags, obj, lock_mode, lockp) * Now we have a lock and an object and we need to see if we should * grant the lock. We use a FIFO ordering so we can only grant a * new lock if it does not conflict with anyone on the holders list - * OR anyone on the waiters list. In case of conflict, we put the - * new lock on the end of the waiters list. + * OR anyone on the waiters list. The reason that we don't grant if + * there's a conflict is that this can lead to starvation (a writer + * waiting on a popularly read item will never ben granted). The + * downside of this is that a waiting reader can prevent an upgrade + * from reader to writer, which is not uncommon. In case of conflict, + * we put the new lock on the end of the waiters list. */ for (lp = SH_TAILQ_FIRST(&sh_obj->holders, __db_lock); lp != NULL; @@ -1042,7 +1048,7 @@ __lock_dump_locker(lt, op) ptr = SH_DBT_PTR(&op->lockobj); memcpy(&locker, ptr, sizeof(u_int32_t)); - printf("L %lu", (u_long)locker); + printf("L %lx", (u_long)locker); lp = SH_LIST_FIRST(&op->heldby, __db_lock); if (lp == NULL) { @@ -1095,7 +1101,7 @@ __lock_is_locked(lt, locker, dbt, mode) lrp = lt->region; /* Look up the object in the hash table. */ - __db_hashlookup(lt->hashtab, __db_lockobj, links, + HASHLOOKUP(lt->hashtab, __db_lockobj, links, dbt, sh_obj, lrp->table_size, __lock_ohash, __lock_cmp); if (sh_obj == NULL) return (0); @@ -1171,7 +1177,7 @@ __lock_printlock(lt, lp, ispgno) stat = "UNKNOWN"; break; } - printf("\t%lu\t%s\t%lu\t%s\t", + printf("\t%lx\t%s\t%lu\t%s\t", (u_long)lp->holder, mode, (u_long)lp->refcount, stat); lockobj = (DB_LOCKOBJ *)((u_int8_t *)lp + lp->obj); @@ -1243,11 +1249,11 @@ __lock_getobj(lt, locker, dbt, type, objp) /* Look up the object in the hash table. */ if (type == DB_LOCK_OBJTYPE) { - __db_hashlookup(lt->hashtab, __db_lockobj, links, dbt, sh_obj, + HASHLOOKUP(lt->hashtab, __db_lockobj, links, dbt, sh_obj, lrp->table_size, __lock_ohash, __lock_cmp); obj_size = dbt->size; } else { - __db_hashlookup(lt->hashtab, __db_lockobj, links, locker, + HASHLOOKUP(lt->hashtab, __db_lockobj, links, locker, sh_obj, lrp->table_size, __lock_locker_hash, __lock_locker_cmp); obj_size = sizeof(locker); @@ -1288,8 +1294,8 @@ __lock_getobj(lt, locker, dbt, type, objp) sh_obj->lockobj.size = obj_size; sh_obj->lockobj.off = SH_PTR_TO_OFF(&sh_obj->lockobj, p); - __db_hashinsert(lt->hashtab, __db_lockobj, links, sh_obj, - lrp->table_size, __lock_lhash); + HASHINSERT(lt->hashtab, + __db_lockobj, links, sh_obj, lrp->table_size, __lock_lhash); if (type == DB_LOCK_LOCKER) lrp->nlockers++; @@ -1325,8 +1331,8 @@ __lock_freeobj(lt, obj) DB_LOCKTAB *lt; DB_LOCKOBJ *obj; { - __db_hashremove_el(lt->hashtab, __db_lockobj, links, - obj, lt->region->table_size, __lock_lhash); + HASHREMOVE_EL(lt->hashtab, + __db_lockobj, links, obj, lt->region->table_size, __lock_lhash); __db_shalloc_free(lt->mem, SH_DBT_PTR(&obj->lockobj)); SH_TAILQ_INSERT_HEAD(<->region->free_objs, obj, links, __db_lockobj); } |