From 4253f875c73c577a768847639e9d2411f935d4d2 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Mon, 3 Sep 2018 20:05:32 +0200 Subject: erts: Fix ets memstat false leak of FixedDeletion causing erlang:memory to report too much ets memory. --- erts/emulator/beam/erl_db_hash.c | 1 + lib/stdlib/test/ets_SUITE.erl | 45 ++++++++++++++++++++++++++++++++++++++-- 2 files changed, 44 insertions(+), 2 deletions(-) diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c index b988a19cf4..b648965885 100644 --- a/erts/emulator/beam/erl_db_hash.c +++ b/erts/emulator/beam/erl_db_hash.c @@ -162,6 +162,7 @@ static ERTS_INLINE int link_fixdel(DbTableHash* tb, if (NFIXED(tb) <= fixated_by_me) { erts_db_free(ERTS_ALC_T_DB_FIX_DEL, (DbTable*)tb, fixd, sizeof(FixedDeletion)); + ERTS_ETS_MISC_MEM_ADD(-sizeof(FixedDeletion)); return 0; /* raced by unfixer */ } exp_next = was_next; diff --git a/lib/stdlib/test/ets_SUITE.erl b/lib/stdlib/test/ets_SUITE.erl index 7a48d1d55e..d8912e548c 100644 --- a/lib/stdlib/test/ets_SUITE.erl +++ b/lib/stdlib/test/ets_SUITE.erl @@ -66,7 +66,7 @@ meta_lookup_named_read/1, meta_lookup_named_write/1, meta_newdel_unnamed/1, meta_newdel_named/1]). -export([smp_insert/1, smp_fixed_delete/1, smp_unfix_fix/1, smp_select_delete/1, - smp_select_replace/1, otp_8166/1, otp_8732/1]). + smp_select_replace/1, otp_8166/1, otp_8732/1, delete_unfix_race/1]). -export([exit_large_table_owner/1, exit_many_large_table_owner/1, exit_many_tables_owner/1, @@ -142,7 +142,8 @@ all() -> ets_all, massive_ets_all, take, - whereis_table]. + whereis_table, + delete_unfix_race]. groups() -> [{new, [], @@ -5489,6 +5490,46 @@ smp_fixed_delete_do() -> %%verify_table_load(T), ets:delete(T). +%% ERL-720 +%% Provoke race between ets:delete and table unfix (by select_count) +%% that caused ets_misc memory counter to indicate false leak. +delete_unfix_race(Config) when is_list(Config) -> + EtsMem = etsmem(), + Table = ets:new(t,[set,public,{write_concurrency,true}]), + InsertOp = + fun() -> + receive stop -> + false + after 0 -> + ets:insert(Table, {rand:uniform(10)}), + true + end + end, + DeleteOp = + fun() -> + receive stop -> + false + after 0 -> + ets:delete(Table, rand:uniform(10)), + true + end + end, + SelectOp = + fun() -> + ets:select_count(Table, ets:fun2ms(fun(X) -> true end)) + end, + Main = self(), + Ins = spawn(fun()-> repeat_while(InsertOp), Main ! self() end), + Del = spawn(fun()-> repeat_while(DeleteOp), Main ! self() end), + spawn(fun()-> + repeat(SelectOp, 10000), + Del ! stop, + Ins ! stop + end), + [receive Pid -> ok end || Pid <- [Ins,Del]], + ets:delete(Table), + verify_etsmem(EtsMem). + num_of_buckets(T) -> element(1,ets:info(T,stats)). -- cgit v1.2.3 From 0e929fc8b8ad2bf3992ebec49c036605eb722a3b Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Mon, 3 Sep 2018 20:24:24 +0200 Subject: erts: Refactor ets FixedDeletion allocations --- erts/emulator/beam/erl_db_hash.c | 46 +++++++++++++++++++++------------------- 1 file changed, 24 insertions(+), 22 deletions(-) diff --git a/erts/emulator/beam/erl_db_hash.c b/erts/emulator/beam/erl_db_hash.c index b648965885..752d3ae3a8 100644 --- a/erts/emulator/beam/erl_db_hash.c +++ b/erts/emulator/beam/erl_db_hash.c @@ -150,6 +150,22 @@ static ERTS_INLINE Uint hash_to_ix(DbTableHash* tb, HashValue hval) } +static ERTS_INLINE FixedDeletion* alloc_fixdel(DbTableHash* tb) +{ + FixedDeletion* fixd = (FixedDeletion*) erts_db_alloc(ERTS_ALC_T_DB_FIX_DEL, + (DbTable *) tb, + sizeof(FixedDeletion)); + ERTS_ETS_MISC_MEM_ADD(sizeof(FixedDeletion)); + return fixd; +} + +static ERTS_INLINE void free_fixdel(DbTableHash* tb, FixedDeletion* fixd) +{ + erts_db_free(ERTS_ALC_T_DB_FIX_DEL, (DbTable*)tb, + fixd, sizeof(FixedDeletion)); + ERTS_ETS_MISC_MEM_ADD(-sizeof(FixedDeletion)); +} + static ERTS_INLINE int link_fixdel(DbTableHash* tb, FixedDeletion* fixd, erts_aint_t fixated_by_me) @@ -160,9 +176,7 @@ static ERTS_INLINE int link_fixdel(DbTableHash* tb, was_next = erts_atomic_read_acqb(&tb->fixdel); do { /* Lockless atomic insertion in linked list: */ if (NFIXED(tb) <= fixated_by_me) { - erts_db_free(ERTS_ALC_T_DB_FIX_DEL, (DbTable*)tb, - fixd, sizeof(FixedDeletion)); - ERTS_ETS_MISC_MEM_ADD(-sizeof(FixedDeletion)); + free_fixdel(tb, fixd); return 0; /* raced by unfixer */ } exp_next = was_next; @@ -181,10 +195,7 @@ static ERTS_INLINE int link_fixdel(DbTableHash* tb, static int add_fixed_deletion(DbTableHash* tb, int ix, erts_aint_t fixated_by_me) { - FixedDeletion* fixd = (FixedDeletion*) erts_db_alloc(ERTS_ALC_T_DB_FIX_DEL, - (DbTable *) tb, - sizeof(FixedDeletion)); - ERTS_ETS_MISC_MEM_ADD(sizeof(FixedDeletion)); + FixedDeletion* fixd = alloc_fixdel(tb); fixd->slot = ix; fixd->all = 0; return link_fixdel(tb, fixd, fixated_by_me); @@ -638,11 +649,7 @@ restart: free_me = fixdel; fixdel = fixdel->next; - erts_db_free(ERTS_ALC_T_DB_FIX_DEL, - (DbTable *) tb, - (void *) free_me, - sizeof(FixedDeletion)); - ERTS_ETS_MISC_MEM_ADD(-sizeof(FixedDeletion)); + free_fixdel(tb, free_me); work++; } @@ -2339,11 +2346,10 @@ static SWord db_mark_all_deleted_hash(DbTable *tbl, SWord reds) } else { /* First call */ - fixdel = erts_db_alloc(ERTS_ALC_T_DB_FIX_DEL, - (DbTable *) tb, - sizeof(FixedDeletion)); - ERTS_ETS_MISC_MEM_ADD(sizeof(FixedDeletion)); - link_fixdel(tb, fixdel, 0); + int ok; + fixdel = alloc_fixdel(tb); + ok = link_fixdel(tb, fixdel, 0); + ASSERT(ok); (void)ok; i = 0; } @@ -2445,11 +2451,7 @@ static SWord db_free_table_continue_hash(DbTable *tbl, SWord reds) FixedDeletion *fx = fixdel; fixdel = fx->next; - erts_db_free(ERTS_ALC_T_DB_FIX_DEL, - (DbTable *) tb, - (void *) fx, - sizeof(FixedDeletion)); - ERTS_ETS_MISC_MEM_ADD(-sizeof(FixedDeletion)); + free_fixdel(tb, fx); if (--reds < 0) { erts_atomic_set_relb(&tb->fixdel, (erts_aint_t)fixdel); return reds; /* Not done */ -- cgit v1.2.3