File 4461-erts-Refactor-dirty_refc-in-ErtsSignalInQueueBufferA.patch of Package erlang

From 2b86199db8cd2d03f4ffcf1cad227e55eebfb591 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Mon, 27 Jun 2022 19:13:42 +0200
Subject: [PATCH 1/4] erts: Refactor dirty_refc in ErtsSignalInQueueBufferArray

No need for 64 bits on 32-bit arch. Can only be +1 per unmanaged thread.

No need for full memory barriers (what I can see).
---
 erts/emulator/beam/erl_message.h        | 2 +-
 erts/emulator/beam/erl_proc_sig_queue.c | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/erts/emulator/beam/erl_message.h b/erts/emulator/beam/erl_message.h
index 87cd96f4cd..afb2c7ca94 100644
--- a/erts/emulator/beam/erl_message.h
+++ b/erts/emulator/beam/erl_message.h
@@ -416,7 +416,7 @@ typedef struct {
      * the buffer array. This is needed since dirty schedulers are not
      * part of the thread progress system.
      */
-    erts_atomic64_t dirty_refc;
+    erts_refc_t dirty_refc;
     Uint nr_of_rounds;
     Uint nr_of_enqueues;
     int alive;
diff --git a/erts/emulator/beam/erl_proc_sig_queue.c b/erts/emulator/beam/erl_proc_sig_queue.c
index 0af9bf6818..37fbfc579f 100644
--- a/erts/emulator/beam/erl_proc_sig_queue.c
+++ b/erts/emulator/beam/erl_proc_sig_queue.c
@@ -8462,7 +8462,7 @@ void erts_proc_sig_queue_maybe_install_buffers(Process* p, erts_aint32_t state)
                          sizeof(ErtsSignalInQueueBufferArray));
     erts_atomic64_init_nob(&buffers->nonempty_slots, (erts_aint64_t)(Uint64)0);
     erts_atomic64_init_nob(&buffers->nonmsg_slots, (erts_aint64_t)(Uint64)0);
-    erts_atomic64_init_nob(&buffers->dirty_refc, (erts_aint64_t)(Uint64)1);
+    erts_refc_init(&buffers->dirty_refc, 1);
     buffers->nr_of_enqueues = 0;
     buffers->nr_of_rounds = 0;
     buffers->alive = 1;
@@ -8500,7 +8500,7 @@ erts_proc_sig_queue_get_buffers(Process* p, int *need_unread)
         erts_thr_progress_unmanaged_continue(dhndl);
         return NULL;
     }
-    erts_atomic64_inc_mb(&buffers->dirty_refc);
+    erts_refc_inc(&buffers->dirty_refc, 2);
     erts_thr_progress_unmanaged_continue(dhndl);
     *need_unread = 1;
     return buffers;
@@ -8513,12 +8513,13 @@ void erts_proc_sig_queue_unget_buffers(ErtsSignalInQueueBufferArray* buffers,
         return;
     } else {
         int i;
-        erts_aint64_t refc = erts_atomic64_dec_read_mb(&buffers->dirty_refc);
-        ASSERT(refc >= 0);
+        erts_aint_t refc = erts_refc_dectest(&buffers->dirty_refc, 0);
         if (refc != 0) {
             return;
         }
+        ASSERT(!buffers->alive);
         for (i = 0; i < ERTS_PROC_SIG_INQ_BUFFERED_NR_OF_BUFFERS; i++) {
+            ASSERT(!buffers->slots[i].b.alive);
             erts_mtx_destroy(&buffers->slots[i].b.lock);
         }
         erts_free(ERTS_ALC_T_SIGQ_BUFFERS, buffers);
-- 
2.35.3