From 0d6dc895744c34c9c52fd42f4801a8a941864ae3 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Mon, 13 Feb 2017 18:22:39 +0100 Subject: Introduce references as table identifiers --- erts/emulator/beam/erl_db.c | 98 ++++++++++++++++++++++++++++++++++++++-- erts/emulator/beam/erl_db_util.h | 2 + 2 files changed, 96 insertions(+), 4 deletions(-) (limited to 'erts/emulator') 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! */ -- cgit v1.2.3