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authorRickard Green <[email protected]>2017-02-13 18:22:39 +0100
committerRickard Green <[email protected]>2017-03-02 16:59:40 +0100
commit0d6dc895744c34c9c52fd42f4801a8a941864ae3 (patch)
tree0897454769a576412c8ddf6605d9dfd5883929e4
parent39b43dd10605f60d580ba9a73136713a776c635d (diff)
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Introduce references as table identifiers
-rw-r--r--erts/emulator/beam/erl_db.c98
-rw-r--r--erts/emulator/beam/erl_db_util.h2
2 files changed, 96 insertions, 4 deletions
diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c
index 9f077dd407..d886c2546a 100644
--- a/erts/emulator/beam/erl_db.c
+++ b/erts/emulator/beam/erl_db.c
@@ -43,6 +43,7 @@
#include "erl_db.h"
#include "bif.h"
#include "big.h"
+#include "erl_binary.h"
erts_smp_atomic_t erts_ets_misc_mem_size;
@@ -113,6 +114,75 @@ static struct {
#define MARK_SLOT_DEAD(i) (meta_main_tab[(i)].u.next_free |= 2)
#define GET_ANY_SLOT_TAB(i) ((DbTable*)(meta_main_tab[(i)].u.next_free & ~(1|2))) /* dead or alive */
+static void schedule_free_dbtable(DbTable* tb);
+
+static void table_dec_refc(DbTable *tb, erts_aint_t min_val)
+{
+ if (erts_smp_refc_dectest(&tb->common.refc, min_val) == 0)
+ schedule_free_dbtable(tb);
+}
+
+static int
+db_table_tid_destructor(Binary *unused)
+{
+ return 1;
+}
+
+static ERTS_INLINE void
+make_btid(DbTable *tb)
+{
+ Binary *btid = erts_create_magic_indirection(db_table_tid_destructor);
+ erts_smp_atomic_t *tbref = erts_smp_binary_to_magic_indirection(btid);
+ erts_smp_atomic_init_nob(tbref, (erts_aint_t) tb);
+ tb->common.btid = btid;
+ /*
+ * Table and magic indirection refer eachother,
+ * and table is refered once by being alive...
+ */
+ erts_smp_refc_init(&tb->common.refc, 2);
+ erts_refc_inc(&btid->refc, 1);
+}
+
+static DbTable *
+tid2tab(Eterm tid)
+{
+ DbTable *tb;
+ Binary *btid;
+ erts_smp_atomic_t *tbref;
+ if (!is_internal_magic_ref(tid))
+ return NULL;
+
+ btid = erts_magic_ref2bin(tid);
+ if (ERTS_MAGIC_BIN_DESTRUCTOR(btid) != db_table_tid_destructor)
+ return NULL;
+
+ tbref = erts_smp_binary_to_magic_indirection(btid);
+ tb = (DbTable *) erts_smp_atomic_read_nob(tbref);
+
+ ASSERT(!tb || tb->common.btid == btid);
+
+ return tb;
+}
+
+static ERTS_INLINE void
+tid_clear(DbTable *tb)
+{
+ DbTable *rtb;
+ Binary *btid = tb->common.btid;
+ erts_smp_atomic_t *tbref = erts_smp_binary_to_magic_indirection(btid);
+ rtb = (DbTable *) erts_smp_atomic_xchg_nob(tbref, (erts_aint_t) NULL);
+ ASSERT(!rtb || tb == rtb);
+ if (rtb)
+ table_dec_refc(tb, 1);
+}
+
+static ERTS_INLINE Eterm
+make_tid(Process *c_p, DbTable *tb)
+{
+ Eterm *hp = HAlloc(c_p, ERTS_MAGIC_REF_THING_SIZE);
+ return erts_mk_magic_ref(&hp, &c_p->off_heap, tb->common.btid);
+}
+
static ERTS_INLINE erts_smp_rwmtx_t *
get_meta_main_tab_lock(unsigned slot)
{
@@ -252,6 +322,10 @@ free_dbtable(void *vtb)
erts_smp_mtx_destroy(&tb->common.fixlock);
#endif
ASSERT(is_immed(tb->common.heir_data));
+
+ if (tb->common.btid && erts_refc_dectest(&tb->common.btid->refc, 0) == 0)
+ erts_bin_free(tb->common.btid);
+
erts_db_free(ERTS_ALC_T_DB_TABLE, tb, (void *) tb, sizeof(DbTable));
}
@@ -266,6 +340,7 @@ static void schedule_free_dbtable(DbTable* tb)
* Caller is *not* allowed to access the specialized part
* (hash or tree) of *tb after this function has returned.
*/
+ ASSERT(erts_smp_refc_read(&tb->common.refc, 0) == 0);
ASSERT(erts_smp_refc_read(&tb->common.ref, 0) == 0);
erts_schedule_thr_prgr_later_cleanup_op(free_dbtable,
(void *) tb,
@@ -375,7 +450,7 @@ DbTable* db_get_table_aux(Process *p,
db_lock_kind_t kind,
int meta_already_locked)
{
- DbTable *tb = NULL;
+ DbTable *tb;
erts_smp_rwmtx_t *mtl = NULL;
/*
@@ -385,7 +460,10 @@ DbTable* db_get_table_aux(Process *p,
*/
ASSERT(erts_get_scheduler_data());
- if (is_small(id)) {
+ tb = tid2tab(id);
+ if (tb)
+ id = tb->common.id;
+ else if (is_small(id)) {
Uint slot = unsigned_val(id) & meta_main_tab_slot_mask;
if (!meta_already_locked) {
mtl = get_meta_main_tab_lock(slot);
@@ -1505,6 +1583,8 @@ BIF_RETTYPE ets_new_2(BIF_ALIST_2)
meth->db_create(BIF_P, tb);
ASSERT(cret == DB_ERROR_NONE);
+ make_btid(tb);
+
erts_smp_spin_lock(&meta_main_tab_main_lock);
if (meta_main_tab_cnt >= db_max_tabs) {
@@ -1539,6 +1619,9 @@ BIF_RETTYPE ets_new_2(BIF_ALIST_2)
tb->common.id = ret;
tb->common.slot = slot; /* store slot for erase */
+ if (!is_named)
+ ret = make_tid(BIF_P, tb);
+
mmtl = get_meta_main_tab_lock(slot);
erts_smp_rwmtx_rwlock(mmtl);
meta_main_tab[slot].u.tb = tb;
@@ -1551,11 +1634,13 @@ BIF_RETTYPE ets_new_2(BIF_ALIST_2)
free_slot(slot);
erts_smp_rwmtx_rwunlock(mmtl);
+ tid_clear(tb);
+
db_lock(tb,LCK_WRITE);
free_heir_data(tb);
tb->common.meth->db_free_table(tb);
- schedule_free_dbtable(tb);
db_unlock(tb,LCK_WRITE);
+ table_dec_refc(tb, 0);
BIF_ERROR(BIF_P, BADARG);
}
@@ -1740,6 +1825,8 @@ BIF_RETTYPE ets_delete_1(BIF_ALIST_1)
UnUseTmpHeap(3,BIF_P);
}
+ tid_clear(tb);
+
mmtl = get_meta_main_tab_lock(tb->common.slot);
#ifdef ERTS_SMP
if (erts_smp_rwmtx_tryrwlock(mmtl) == EBUSY) {
@@ -2969,6 +3056,7 @@ void init_db(ErtsDbSpinCount db_spin_count)
erts_smp_atomic_read_nob(&init_tb.common.memory_size));
meta_pid_to_tab->common.id = NIL;
+ meta_pid_to_tab->common.btid = NULL;
meta_pid_to_tab->common.the_name = am_true;
meta_pid_to_tab->common.status = (DB_NORMAL | DB_BAG | DB_PUBLIC | DB_FINE_LOCKED);
#ifdef ERTS_SMP
@@ -3000,6 +3088,7 @@ void init_db(ErtsDbSpinCount db_spin_count)
erts_smp_atomic_read_nob(&init_tb.common.memory_size));
meta_pid_to_fixed_tab->common.id = NIL;
+ meta_pid_to_fixed_tab->common.btid = NULL;
meta_pid_to_fixed_tab->common.the_name = am_true;
meta_pid_to_fixed_tab->common.status = (DB_NORMAL | DB_BAG | DB_PUBLIC | DB_FINE_LOCKED);
#ifdef ERTS_SMP
@@ -3295,6 +3384,7 @@ erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks)
#endif
first_call = (tb->common.status & DB_DELETE) == 0;
if (first_call) {
+ tid_clear(tb);
/* Clear all access bits. */
tb->common.status &= ~(DB_PROTECTED
| DB_PUBLIC
@@ -3707,7 +3797,7 @@ static int free_table_cont(Process *p,
make_small(tb->common.slot));
db_meta_unlock(meta_pid_to_tab, LCK_WRITE_REC);
}
- schedule_free_dbtable(tb);
+ table_dec_refc(tb, 0);
BUMP_REDS(p, 100);
return 0;
}
diff --git a/erts/emulator/beam/erl_db_util.h b/erts/emulator/beam/erl_db_util.h
index 471fefe3cb..3f507b559f 100644
--- a/erts/emulator/beam/erl_db_util.h
+++ b/erts/emulator/beam/erl_db_util.h
@@ -212,6 +212,7 @@ typedef struct db_fixation {
*/
typedef struct db_table_common {
+ erts_smp_refc_t refc; /* reference count of table struct */
erts_smp_refc_t ref; /* fixation counter */
#ifdef ERTS_SMP
erts_smp_rwmtx_t rwlock; /* rw lock on table */
@@ -225,6 +226,7 @@ typedef struct db_table_common {
Uint64 heir_started_interval; /* To further identify the heir */
Eterm the_name; /* an atom */
Eterm id; /* atom | integer */
+ Binary *btid;
DbTableMethod* meth; /* table methods */
erts_smp_atomic_t nitems; /* Total number of items in table */
erts_smp_atomic_t memory_size;/* Total memory size. NOTE: in bytes! */