summaryrefslogtreecommitdiff
path: root/db2/lock
diff options
context:
space:
mode:
Diffstat (limited to 'db2/lock')
-rw-r--r--db2/lock/lock.c40
-rw-r--r--db2/lock/lock_deadlock.c9
2 files changed, 27 insertions, 22 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(&lt->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(&lt->region->free_objs, obj, links, __db_lockobj);
}
diff --git a/db2/lock/lock_deadlock.c b/db2/lock/lock_deadlock.c
index f753958b21..f947f901c3 100644
--- a/db2/lock/lock_deadlock.c
+++ b/db2/lock/lock_deadlock.c
@@ -11,7 +11,7 @@
static const char copyright[] =
"@(#) Copyright (c) 1997\n\
Sleepycat Software Inc. All rights reserved.\n";
-static const char sccsid[] = "@(#)lock_deadlock.c 10.20 (Sleepycat) 8/21/97";
+static const char sccsid[] = "@(#)lock_deadlock.c 10.21 (Sleepycat) 9/6/97";
#endif
#ifndef NO_SYSTEM_INCLUDES
@@ -300,8 +300,8 @@ retry: count = lt->region->nlockers;
for (lp = SH_TAILQ_FIRST(&op->holders, __db_lock);
lp != NULL;
lp = SH_TAILQ_NEXT(lp, links, __db_lock)) {
- if ((__set_errno(__lock_getobj(lt, lp->holder,
- NULL, DB_LOCK_LOCKER, &lockerp))) != 0) {
+ if (__lock_getobj(lt, lp->holder,
+ NULL, DB_LOCK_LOCKER, &lockerp) != 0) {
__db_err(dbenv,
"warning unable to find object");
continue;
@@ -472,8 +472,7 @@ __dd_debug(dbenv, idmap, bitmap, nlockers)
* Alloc space to print 10 bytes per item waited on.
*/
if ((msgbuf = (char *)malloc((nlockers + 1) * 10 + 64)) == NULL) {
- __set_errno(ENOMEM);
- __db_err(dbenv, "%s", strerror(errno));
+ __db_err(dbenv, "%s", strerror(ENOMEM));
return;
}
View Lorry Controller Status