File 1332-erts-Fix-reference-counting-of-magic-refs-in-ETS-com.patch of Package erlang
From 41febafc004070e0059129bf692deacd69117259 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Thu, 29 Jun 2023 19:46:52 +0200
Subject: [PATCH] erts: Fix reference counting of magic refs in ETS compressed
format
Store the EtrsMRefThing as is like we do for ProcBin,
in order to link them into off-heap list.
---
erts/emulator/beam/erl_bif_info.c | 2 +-
erts/emulator/beam/erl_db_util.c | 4 +--
erts/emulator/beam/erl_db_util.h | 26 +++++++++++------
erts/emulator/beam/erl_node_tables.c | 2 +-
erts/emulator/beam/external.c | 43 ++++++++++++++++++++++++++--
erts/emulator/beam/external.h | 1 +
lib/stdlib/test/ets_SUITE.erl | 24 ++++++++++++++++
7 files changed, 87 insertions(+), 15 deletions(-)
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index d5e598515c..98b0f480e0 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -170,7 +170,7 @@ erts_bld_bin_list(Uint **hpp, Uint *szp, ErlOffHeap* oh, Eterm tail)
union erl_off_heap_ptr u;
Eterm res = tail;
Eterm tuple;
- struct erts_tmp_aligned_offheap tmp;
+ union erts_tmp_aligned_offheap tmp;
for (u.hdr = oh->first; u.hdr; u.hdr = u.hdr->next) {
erts_align_offheap(&u, &tmp);
diff --git a/erts/emulator/beam/erl_db_util.c b/erts/emulator/beam/erl_db_util.c
index 8bace68d0f..60bad7b652 100644
--- a/erts/emulator/beam/erl_db_util.c
+++ b/erts/emulator/beam/erl_db_util.c
@@ -3389,12 +3389,12 @@ Eterm db_copy_element_from_ets(DbTableCommon* tb, Process* p,
/* Our own "cleanup_offheap"
- * as refc-binaries may be unaligned in compressed terms
+ * as ProcBin and ErtsMRefThing may be unaligned in compressed terms
*/
void db_cleanup_offheap_comp(DbTerm* obj)
{
union erl_off_heap_ptr u;
- struct erts_tmp_aligned_offheap tmp;
+ union erts_tmp_aligned_offheap tmp;
for (u.hdr = obj->first_oh; u.hdr; u.hdr = u.hdr->next) {
erts_align_offheap(&u, &tmp);
diff --git a/erts/emulator/beam/erl_db_util.h b/erts/emulator/beam/erl_db_util.h
index 6ed1e15104..db1113676e 100644
--- a/erts/emulator/beam/erl_db_util.h
+++ b/erts/emulator/beam/erl_db_util.h
@@ -570,14 +570,15 @@ ERTS_GLB_INLINE Binary *erts_db_get_match_prog_binary_unchecked(Eterm term);
/** @brief Ensure off-heap header is word aligned, make a temporary copy if
* not. Needed when inspecting ETS off-heap lists that may contain unaligned
- * ProcBins if table is 'compressed'.
+ * ProcBin and ErtsMRefThing if table is 'compressed'.
*/
-struct erts_tmp_aligned_offheap
+union erts_tmp_aligned_offheap
{
ProcBin proc_bin;
+ ErtsMRefThing mref_thing;
};
ERTS_GLB_INLINE void erts_align_offheap(union erl_off_heap_ptr*,
- struct erts_tmp_aligned_offheap* tmp);
+ union erts_tmp_aligned_offheap* tmp);
#if ERTS_GLB_INLINE_INCL_FUNC_DEF
@@ -613,20 +614,27 @@ erts_db_get_match_prog_binary(Eterm term)
ERTS_GLB_INLINE void
erts_align_offheap(union erl_off_heap_ptr* ohp,
- struct erts_tmp_aligned_offheap* tmp)
+ union erts_tmp_aligned_offheap* tmp)
{
if ((UWord)ohp->voidp % sizeof(UWord) != 0) {
/*
- * ETS store word unaligned ProcBins in its compressed format.
- * Make a temporary aligned copy.
+ * ETS store word unaligned ProcBin and ErtsMRefThing in its compressed
+ * format. Make a temporary aligned copy.
*
* Warning, must pass (void*)-variable to memcpy. Otherwise it will
* cause Bus error on Sparc due to false compile time assumptions
* about word aligned memory (type cast is not enough).
*/
- sys_memcpy(tmp, ohp->voidp, sizeof(*tmp));
- ASSERT(tmp->proc_bin.thing_word == HEADER_PROC_BIN);
- ohp->pb = &tmp->proc_bin;
+ sys_memcpy(tmp, ohp->voidp, sizeof(Eterm)); /* thing_word */
+ if (tmp->proc_bin.thing_word == HEADER_PROC_BIN) {
+ sys_memcpy(tmp, ohp->voidp, sizeof(tmp->proc_bin));
+ ohp->pb = &tmp->proc_bin;
+ }
+ else {
+ sys_memcpy(tmp, ohp->voidp, sizeof(tmp->mref_thing));
+ ASSERT(is_magic_ref_thing(&tmp->mref_thing));
+ ohp->mref = &tmp->mref_thing;
+ }
}
}
diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index 912caf5ace..7b5ff65756 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -1514,7 +1514,7 @@ static void
insert_offheap(ErlOffHeap *oh, int type, Eterm id)
{
union erl_off_heap_ptr u;
- struct erts_tmp_aligned_offheap tmp;
+ union erts_tmp_aligned_offheap tmp;
struct insert_offheap2_arg a;
a.type = BIN_REF;
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 67584e38ec..ef09681d39 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -3380,7 +3380,22 @@ enc_term_int(TTBEncodeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj, byte* ep,
ep = enc_pid(acmp, obj, ep, dflags);
break;
- case REF_DEF:
+ case REF_DEF:
+ if ((dflags & DFLAG_ETS_COMPRESSED) && is_internal_magic_ref(obj)) {
+ ErtsMRefThing tmp;
+ ErtsMRefThing *mrtp = (ErtsMRefThing *) internal_ref_val(obj);
+
+ erts_refc_inc(&mrtp->mb->intern.refc, 2);
+
+ *ep++ = MAGIC_REF_INTERNAL_REF;
+ sys_memcpy(&tmp, mrtp, sizeof(ErtsMRefThing));
+ tmp.next = *off_heap;
+ sys_memcpy(ep, &tmp, sizeof(ErtsMRefThing));
+ *off_heap = (struct erl_off_heap_header*) ep;
+ ep += sizeof(ErtsMRefThing);
+ break;
+ }
+ /*else fall through */
case EXTERNAL_REF_DEF: {
Uint32 *ref_num;
Eterm sysname = (((dflags & DFLAG_ETS_COMPRESSED) && is_internal_ref(obj))
@@ -5011,6 +5026,19 @@ dec_term_atom_common:
*objp = make_binary(sub);
break;
}
+ case MAGIC_REF_INTERNAL_REF:
+ {
+ ErtsMRefThing* mrtp = (ErtsMRefThing*) hp;
+ sys_memcpy(mrtp, ep, sizeof(ErtsMRefThing));
+ ep += sizeof(ErtsMRefThing);
+ erts_refc_inc(&mrtp->mb->intern.refc, 2);
+ hp += ERTS_MAGIC_REF_THING_SIZE;
+ mrtp->next = factory->off_heap->first;
+ factory->off_heap->first = (struct erl_off_heap_header*)mrtp;
+ *objp = make_internal_ref(mrtp);
+ ASSERT(is_internal_magic_ref(*objp));
+ break;
+ }
default:
goto error;
@@ -5231,8 +5259,13 @@ encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
result += (1 + encode_size_struct2(acmp, pid_node_name(obj), dflags) +
4 + 4 + 4);
break;
+ case REF_DEF:
+ if ((dflags & DFLAG_ETS_COMPRESSED) && is_internal_magic_ref(obj)) {
+ result += 1 + sizeof(ErtsMRefThing);
+ break;
+ }
+ /* else fall through */
case EXTERNAL_REF_DEF:
- case REF_DEF:
ASSERT(dflags & DFLAG_EXTENDED_REFERENCES);
i = ref_no_numbers(obj);
result += (1 + 2 + encode_size_struct2(acmp, ref_node_name(obj), dflags) +
@@ -5883,6 +5916,12 @@ init_done:
SKIP(2+sizeof(ProcBin));
heap_size += PROC_BIN_SIZE + ERL_SUB_BIN_SIZE;
break;
+ case MAGIC_REF_INTERNAL_REF:
+ if (!internal_tags)
+ goto error;
+ SKIP(sizeof(ErtsMRefThing));
+ heap_size += ERTS_MAGIC_REF_THING_SIZE;
+ break;
default:
goto error;
}
diff --git a/erts/emulator/beam/external.h b/erts/emulator/beam/external.h
index 7a59d02102..41171a3336 100644
--- a/erts/emulator/beam/external.h
+++ b/erts/emulator/beam/external.h
@@ -67,6 +67,7 @@
#define ATOM_INTERNAL_REF3 'K'
#define BINARY_INTERNAL_REF 'J'
#define BIT_BINARY_INTERNAL_REF 'L'
+#define MAGIC_REF_INTERNAL_REF 'N'
#define COMPRESSED 'P'
#if 0
diff --git a/lib/stdlib/test/ets_SUITE.erl b/lib/stdlib/test/ets_SUITE.erl
index 588096301d..c006f4ed25 100644
--- a/lib/stdlib/test/ets_SUITE.erl
+++ b/lib/stdlib/test/ets_SUITE.erl
@@ -96,6 +96,7 @@
-export([otp_9932/1]).
-export([otp_9423/1]).
-export([otp_10182/1]).
+-export([compress_magic_ref/1]).
-export([ets_all/1]).
-export([massive_ets_all/1]).
-export([take/1]).
@@ -168,6 +169,7 @@ all() ->
otp_10182,
otp_9932,
otp_9423,
+ compress_magic_ref,
ets_all,
massive_ets_all,
take,
@@ -7280,6 +7282,28 @@ otp_10182(Config) when is_list(Config) ->
In = Out
end).
+%% Verify magic refs in compressed table are reference counted correctly
+compress_magic_ref(Config) when is_list(Config)->
+ F = fun(Opts) ->
+ T = ets:new(banana, Opts),
+ ets:insert(T, {key, atomics:new(2, [])}),
+ erlang:garbage_collect(), % make really sure no ref on heap
+ [{_, Ref}] = ets:lookup(T, key),
+ #{size := 2} = atomics:info(Ref), % Still alive!
+
+ %% Now test ets:delete will deallocate if last ref
+ WeakRef = term_to_binary(Ref),
+ erlang:garbage_collect(), % make sure no Ref on heap
+ ets:delete(T, key),
+ StaleRef = binary_to_term(WeakRef),
+ badarg = try atomics:info(StaleRef)
+ catch error:badarg -> badarg end,
+ ets:delete(T),
+ ok
+ end,
+ repeat_for_opts(F, [[set, ordered_set], compressed]),
+ ok.
+
%% Test that ets:all include/exclude tables that we know are created/deleted
ets_all(Config) when is_list(Config) ->
Pids = [spawn_link(fun() -> ets_all_run() end) || _ <- [1,2]],
--
2.35.3
