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Diffstat (limited to 'erts/emulator/beam/erl_db_hash.c')
-rw-r--r--erts/emulator/beam/erl_db_hash.c104
1 files changed, 62 insertions, 42 deletions
diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c
index 81b0c4465c..0b31eb3bcd 100644
--- a/erts/emulator/beam/erl_db_hash.c
+++ b/erts/emulator/beam/erl_db_hash.c
@@ -148,8 +148,11 @@ static ERTS_INLINE Uint hash_to_ix(DbTableHash* tb, HashValue hval)
}
/* Remember a slot containing a pseudo-deleted item (INVALID_HASH)
-*/
-static ERTS_INLINE void add_fixed_deletion(DbTableHash* tb, int ix)
+ * Return false if we got raced by unfixing thread
+ * and the object should be deleted for real.
+ */
+static ERTS_INLINE int add_fixed_deletion(DbTableHash* tb, int ix,
+ erts_aint_t fixated_by_me)
{
erts_aint_t was_next;
erts_aint_t exp_next;
@@ -160,12 +163,18 @@ static ERTS_INLINE void add_fixed_deletion(DbTableHash* tb, int ix)
fixd->slot = ix;
was_next = erts_smp_atomic_read_acqb(&tb->fixdel);
do { /* Lockless atomic insertion in linked list: */
- exp_next = was_next;
+ if (NFIXED(tb) <= fixated_by_me) {
+ erts_db_free(ERTS_ALC_T_DB_FIX_DEL, (DbTable*)tb,
+ fixd, sizeof(FixedDeletion));
+ return 0; /* raced by unfixer */
+ }
+ exp_next = was_next;
fixd->next = (FixedDeletion*) exp_next;
- was_next = erts_smp_atomic_cmpxchg_relb(&tb->fixdel,
- (erts_aint_t) fixd,
- exp_next);
+ was_next = erts_smp_atomic_cmpxchg_mb(&tb->fixdel,
+ (erts_aint_t) fixd,
+ exp_next);
}while (was_next != exp_next);
+ return 1;
}
@@ -607,8 +616,8 @@ void db_unfix_table_hash(DbTableHash *tb)
|| (erts_smp_lc_rwmtx_is_rlocked(&tb->common.rwlock)
&& !tb->common.is_thread_safe));
restart:
- fixdel = (FixedDeletion*) erts_smp_atomic_xchg_acqb(&tb->fixdel,
- (erts_aint_t) NULL);
+ fixdel = (FixedDeletion*) erts_smp_atomic_xchg_mb(&tb->fixdel,
+ (erts_aint_t) NULL);
while (fixdel != NULL) {
FixedDeletion *fx = fixdel;
int ix = fx->slot;
@@ -1142,9 +1151,9 @@ int db_erase_hash(DbTable *tbl, Eterm key, Eterm *ret)
while(b != 0) {
if (has_live_key(tb,b,key,hval)) {
--nitems_diff;
- if (nitems_diff == -1 && IS_FIXED(tb)) {
+ if (nitems_diff == -1 && IS_FIXED(tb)
+ && add_fixed_deletion(tb, ix, 0)) {
/* Pseudo remove (no need to keep several of same key) */
- add_fixed_deletion(tb, ix);
b->hvalue = INVALID_HASH;
} else {
*bp = b->next;
@@ -1196,9 +1205,8 @@ static int db_erase_object_hash(DbTable *tbl, Eterm object, Eterm *ret)
++nkeys;
if (db_eq(&tb->common,object, &b->dbterm)) {
--nitems_diff;
- if (nkeys==1 && IS_FIXED(tb)) { /* Pseudo remove */
- add_fixed_deletion(tb,ix);
- b->hvalue = INVALID_HASH;
+ if (nkeys==1 && IS_FIXED(tb) && add_fixed_deletion(tb,ix,0)) {
+ b->hvalue = INVALID_HASH; /* Pseudo remove */
bp = &b->next;
b = b->next;
} else {
@@ -1820,14 +1828,17 @@ static int db_select_delete_hash(Process *p,
int did_erase = 0;
if (db_match_dbterm(&tb->common, p, mpi.mp, 0,
&(*current)->dbterm, NULL, 0) == am_true) {
+ HashDbTerm *del;
if (NFIXED(tb) > fixated_by_me) { /* fixated by others? */
if (slot_ix != last_pseudo_delete) {
- add_fixed_deletion(tb, slot_ix);
- last_pseudo_delete = slot_ix;
+ if (!add_fixed_deletion(tb, slot_ix, fixated_by_me))
+ goto do_erase;
+ last_pseudo_delete = slot_ix;
}
(*current)->hvalue = INVALID_HASH;
} else {
- HashDbTerm *del = *current;
+ do_erase:
+ del = *current;
*current = (*current)->next;
free_term(tb, del);
did_erase = 1;
@@ -1931,14 +1942,17 @@ static int db_select_delete_continue_hash(Process *p,
int did_erase = 0;
if (db_match_dbterm(&tb->common, p, mp, 0,
&(*current)->dbterm, NULL, 0) == am_true) {
+ HashDbTerm *del;
if (NFIXED(tb) > fixated_by_me) { /* fixated by others? */
if (slot_ix != last_pseudo_delete) {
- add_fixed_deletion(tb, slot_ix);
+ if (!add_fixed_deletion(tb, slot_ix, fixated_by_me))
+ goto do_erase;
last_pseudo_delete = slot_ix;
}
(*current)->hvalue = INVALID_HASH;
} else {
- HashDbTerm *del = *current;
+ do_erase:
+ del = *current;
*current = (*current)->next;
free_term(tb, del);
did_erase = 1;
@@ -2089,9 +2103,9 @@ static int db_take_hash(Process *p, DbTable *tbl, Eterm key, Eterm *ret)
*ret = get_term_list(p, tb, key, hval, b, &bend);
while (b != bend) {
--nitems_diff;
- if (nitems_diff == -1 && IS_FIXED(tb)) {
+ if (nitems_diff == -1 && IS_FIXED(tb)
+ && add_fixed_deletion(tb, ix, 0)) {
/* Pseudo remove (no need to keep several of same key) */
- add_fixed_deletion(tb, ix);
bp = &b->next;
b->hvalue = INVALID_HASH;
b = b->next;
@@ -2131,7 +2145,7 @@ int db_mark_all_deleted_hash(DbTable *tbl)
for (i = 0; i < NACTIVE(tb); i++) {
if ((list = BUCKET(tb,i)) != NULL) {
- add_fixed_deletion(tb, i);
+ add_fixed_deletion(tb, i, 0);
do {
list->hvalue = INVALID_HASH;
list = list->next;
@@ -2855,15 +2869,7 @@ db_lookup_dbterm_hash(Process *p, DbTable *tbl, Eterm key, Eterm obj,
q->hvalue = hval;
q->next = NULL;
*bp = b = q;
-
- {
- int nitems = erts_smp_atomic_inc_read_nob(&tb->common.nitems);
- int nactive = NACTIVE(tb);
-
- if (nitems > nactive * (CHAIN_LEN + 1) && !IS_FIXED(tb)) {
- grow(tb, nactive);
- }
- }
+ flags |= DB_INC_TRY_GROW;
} else {
HashDbTerm *q, *next = b->next;
@@ -2902,32 +2908,46 @@ db_finalize_dbterm_hash(int cret, DbUpdateHandle* handle)
HashDbTerm **bp = (HashDbTerm **) handle->bp;
HashDbTerm *b = *bp;
erts_smp_rwmtx_t* lck = (erts_smp_rwmtx_t*) handle->lck;
+ HashDbTerm* free_me = NULL;
ERTS_SMP_LC_ASSERT(IS_HASH_WLOCKED(tb, lck)); /* locked by db_lookup_dbterm_hash */
ASSERT((&b->dbterm == handle->dbterm) == !(tb->common.compress && handle->flags & DB_MUST_RESIZE));
if (handle->flags & DB_NEW_OBJECT && cret != DB_ERROR_NONE) {
- if (IS_FIXED(tb)) {
- add_fixed_deletion(tb, hash_to_ix(tb, b->hvalue));
+ if (IS_FIXED(tb) && add_fixed_deletion(tb, hash_to_ix(tb, b->hvalue),
+ 0)) {
b->hvalue = INVALID_HASH;
} else {
*bp = b->next;
- free_term(tb, b);
+ free_me = b;
}
WUNLOCK_HASH(lck);
erts_smp_atomic_dec_nob(&tb->common.nitems);
try_shrink(tb);
- } else if (handle->flags & DB_MUST_RESIZE) {
- db_finalize_resize(handle, offsetof(HashDbTerm,dbterm));
- WUNLOCK_HASH(lck);
-
- free_term(tb, b);
- }
- else {
- WUNLOCK_HASH(lck);
+ } else {
+ if (handle->flags & DB_MUST_RESIZE) {
+ db_finalize_resize(handle, offsetof(HashDbTerm,dbterm));
+ free_me = b;
+ }
+ if (handle->flags & DB_INC_TRY_GROW) {
+ int nactive;
+ int nitems = erts_smp_atomic_inc_read_nob(&tb->common.nitems);
+ WUNLOCK_HASH(lck);
+ nactive = NACTIVE(tb);
+
+ if (nitems > nactive * (CHAIN_LEN + 1) && !IS_FIXED(tb)) {
+ grow(tb, nactive);
+ }
+ } else {
+ WUNLOCK_HASH(lck);
+ }
}
+
+ if (free_me)
+ free_term(tb, free_me);
+
#ifdef DEBUG
handle->dbterm = 0;
#endif
@@ -3014,7 +3034,7 @@ void db_check_table_hash(DbTable *tbl)
if ((list = BUCKET(tb,j)) != 0) {
while (list != 0) {
if (!is_tuple(make_tuple(list->dbterm.tpl))) {
- erl_exit(1, "Bad term in slot %d of ets table", j);
+ erts_exit(ERTS_ERROR_EXIT, "Bad term in slot %d of ets table", j);
}
list = list->next;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-02 12:09:18 +0000