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$NetBSD: patch-bc,v 1.1 2009/01/21 15:44:32 drochner Exp $
--- lock/lock_deadlock.c.orig 2009-01-16 19:58:12.000000000 +0100
+++ lock/lock_deadlock.c
@@ -121,7 +121,7 @@ __lock_detect(env, atype, rejectp)
DB_LOCKTAB *lt;
db_timespec now;
locker_info *idmap;
- u_int32_t *bitmap, *copymap, **deadp, **free_me, *tmpmap;
+ u_int32_t *bitmap, *copymap, **deadp, **deadlist, *tmpmap;
u_int32_t i, cid, keeper, killid, limit, nalloc, nlockers;
u_int32_t lock_max, txn_max;
int ret, status;
@@ -133,7 +133,8 @@ __lock_detect(env, atype, rejectp)
if (IS_REP_CLIENT(env))
atype = DB_LOCK_MINWRITE;
- free_me = NULL;
+ copymap = tmpmap = NULL;
+ deadlist = NULL;
lt = env->lk_handle;
if (rejectp != NULL)
@@ -179,11 +180,11 @@ __lock_detect(env, atype, rejectp)
memcpy(copymap, bitmap, nlockers * sizeof(u_int32_t) * nalloc);
if ((ret = __os_calloc(env, sizeof(u_int32_t), nalloc, &tmpmap)) != 0)
- goto err1;
+ goto err;
/* Find a deadlock. */
if ((ret =
- __dd_find(env, bitmap, idmap, nlockers, nalloc, &deadp)) != 0)
+ __dd_find(env, bitmap, idmap, nlockers, nalloc, &deadlist)) != 0)
return (ret);
/*
@@ -204,8 +205,7 @@ __lock_detect(env, atype, rejectp)
txn_max = TXN_MAXIMUM;
killid = BAD_KILLID;
- free_me = deadp;
- for (; *deadp != NULL; deadp++) {
+ for (deadp = deadlist; *deadp != NULL; deadp++) {
if (rejectp != NULL)
++*rejectp;
killid = (u_int32_t)(*deadp - bitmap) / nalloc;
@@ -342,11 +342,12 @@ dokill: if (killid == BAD_KILLID) {
__db_msg(env,
"Aborting locker %lx", (u_long)idmap[killid].id);
}
- __os_free(env, tmpmap);
-err1: __os_free(env, copymap);
-
-err: if (free_me != NULL)
- __os_free(env, free_me);
+err: if(copymap != NULL)
+ __os_free(env, copymap);
+ if (deadlist != NULL)
+ __os_free(env, deadlist);
+ if(tmpmap != NULL)
+ __os_free(env, tmpmap);
__os_free(env, bitmap);
__os_free(env, idmap);
@@ -360,6 +361,17 @@ err: if (free_me != NULL)
#define DD_INVALID_ID ((u_int32_t) -1)
+/*
+ * __dd_build --
+ * Build the lock dependency bit maps.
+ * Notes on syncronization:
+ * LOCK_SYSTEM_LOCK is used to hold objects locked when we have
+ * a single partition.
+ * LOCK_LOCKERS is held while we are walking the lockers list and
+ * to single thread the use of lockerp->dd_id.
+ * LOCK_DD protects the DD list of objects.
+ */
+
static int
__dd_build(env, atype, bmp, nlockers, allocp, idmap, rejectp)
ENV *env;
@@ -393,6 +405,7 @@ __dd_build(env, atype, bmp, nlockers, al
* In particular we do not build the conflict array and our caller
* needs to expect this.
*/
+ LOCK_SYSTEM_LOCK(lt, region);
if (atype == DB_LOCK_EXPIRE) {
skip: LOCK_DD(env, region);
op = SH_TAILQ_FIRST(®ion->dd_objs, __db_lockobj);
@@ -430,17 +443,18 @@ skip: LOCK_DD(env, region);
OBJECT_UNLOCK(lt, region, indx);
}
UNLOCK_DD(env, region);
+ LOCK_SYSTEM_UNLOCK(lt, region);
goto done;
}
/*
- * We'll check how many lockers there are, add a few more in for
- * good measure and then allocate all the structures. Then we'll
- * verify that we have enough room when we go back in and get the
- * mutex the second time.
+ * Allocate after locking the region
+ * to make sure the structures are large enough.
*/
-retry: count = region->stat.st_nlockers;
+ LOCK_LOCKERS(env, region);
+ count = region->stat.st_nlockers;
if (count == 0) {
+ UNLOCK_LOCKERS(env, region);
*nlockers = 0;
return (0);
}
@@ -448,50 +462,37 @@ retry: count = region->stat.st_nlockers;
if (FLD_ISSET(env->dbenv->verbose, DB_VERB_DEADLOCK))
__db_msg(env, "%lu lockers", (u_long)count);
- count += 20;
nentries = (u_int32_t)DB_ALIGN(count, 32) / 32;
- /*
- * Allocate enough space for a count by count bitmap matrix.
- *
- * XXX
- * We can probably save the malloc's between iterations just
- * reallocing if necessary because count grew by too much.
- */
+ /* Allocate enough space for a count by count bitmap matrix. */
if ((ret = __os_calloc(env, (size_t)count,
- sizeof(u_int32_t) * nentries, &bitmap)) != 0)
+ sizeof(u_int32_t) * nentries, &bitmap)) != 0) {
+ UNLOCK_LOCKERS(env, region);
return (ret);
+ }
if ((ret = __os_calloc(env,
sizeof(u_int32_t), nentries, &tmpmap)) != 0) {
+ UNLOCK_LOCKERS(env, region);
__os_free(env, bitmap);
return (ret);
}
if ((ret = __os_calloc(env,
(size_t)count, sizeof(locker_info), &id_array)) != 0) {
+ UNLOCK_LOCKERS(env, region);
__os_free(env, bitmap);
__os_free(env, tmpmap);
return (ret);
}
/*
- * Now go back in and actually fill in the matrix.
- */
- if (region->stat.st_nlockers > count) {
- __os_free(env, bitmap);
- __os_free(env, tmpmap);
- __os_free(env, id_array);
- goto retry;
- }
-
- /*
* First we go through and assign each locker a deadlock detector id.
*/
id = 0;
- LOCK_LOCKERS(env, region);
SH_TAILQ_FOREACH(lip, ®ion->lockers, ulinks, __db_locker) {
if (lip->master_locker == INVALID_ROFF) {
+ DB_ASSERT(env, id < count);
lip->dd_id = id++;
id_array[lip->dd_id].id = lip->id;
switch (atype) {
@@ -510,7 +511,6 @@ retry: count = region->stat.st_nlockers;
lip->dd_id = DD_INVALID_ID;
}
- UNLOCK_LOCKERS(env, region);
/*
* We only need consider objects that have waiters, so we use
@@ -669,7 +669,6 @@ again: memset(bitmap, 0, count * sizeof
* status after building the bit maps so that we will not detect
* a blocked transaction without noting that it is already aborting.
*/
- LOCK_LOCKERS(env, region);
for (id = 0; id < count; id++) {
if (!id_array[id].valid)
continue;
@@ -738,6 +737,7 @@ get_lock: id_array[id].last_lock = R_OF
id_array[id].in_abort = 1;
}
UNLOCK_LOCKERS(env, region);
+ LOCK_SYSTEM_UNLOCK(lt, region);
/*
* Now we can release everything except the bitmap matrix that we
@@ -839,6 +839,7 @@ __dd_abort(env, info, statusp)
ret = 0;
/* We must lock so this locker cannot go away while we abort it. */
+ LOCK_SYSTEM_LOCK(lt, region);
LOCK_LOCKERS(env, region);
/*
@@ -895,6 +896,7 @@ __dd_abort(env, info, statusp)
done: OBJECT_UNLOCK(lt, region, info->last_ndx);
err:
out: UNLOCK_LOCKERS(env, region);
+ LOCK_SYSTEM_UNLOCK(lt, region);
return (ret);
}
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