From e3b929aa878178773eb19bf10143be5f81e32e06 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Wed, 25 Apr 2018 08:35:05 +0200
Subject: [PATCH] core: jam-scaper/garbage-collector: Use only one arena.

* src/mes.c (ARENA_SIZE): Lower to 200000.
  (MES_MAX_ARENA): Bump to 300000000.
  (JAM_SIZE): New global.
  (make_cell__): Remove ARENA assert.
  (gc_init_cells): Alloc ARENA_SIZE + JAM_SIZE.
  (mes_symbols): Do not init news.
  (gc_init_news): Remove.
  (main): Initialize JAM_SIZE, consider MES_JAM environment variable.
* src/gc.c (gc_init_news): Move from mes.c.  Start at g_free.
  (gc_flip): Do not flip to g_news, instead copy g_news to cells.
  (gc_up_arena): Realloc to ARENA_SIZE + JAM_SIZE.
  (gc_): Init news.  Only up arena if g_news is safe.
---
 src/gc.c  | 36 +++++++++++++++++++++++++++---------
 src/mes.c | 40 +++++++++++-----------------------------
 2 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/src/gc.c b/src/gc.c
index e1600c4d..71751252 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -23,8 +23,15 @@
 SCM
 gc_up_arena () ///((internal))
 {
-  ARENA_SIZE *= 2;
-  void *p = realloc (g_cells-1, 2*ARENA_SIZE*sizeof(struct scm));
+  if (ARENA_SIZE >> 1 < MAX_ARENA_SIZE >> 2)
+    {
+      ARENA_SIZE <<= 1;
+      JAM_SIZE <<= 1;
+      GC_SAFETY <<= 1;
+    }
+  else
+    ARENA_SIZE = MAX_ARENA_SIZE -JAM_SIZE;
+  void *p = realloc (g_cells-1, (ARENA_SIZE+JAM_SIZE)*sizeof (struct scm));
   if (!p)
     {
       eputs ("realloc failed, g_free=");
@@ -37,7 +44,6 @@ gc_up_arena () ///((internal))
     }
   g_cells = (struct scm*)p;
   g_cells++;
-  gc_init_news ();
 
   return 0;
 }
@@ -45,15 +51,15 @@ gc_up_arena () ///((internal))
 SCM
 gc_flip () ///((internal))
 {
-  struct scm *cells = g_cells;
-  g_cells = g_news;
-  g_news = cells;
   if (g_debug > 2)
     {
       eputs (";;;   => jam[");
       eputs (itoa (g_free));
       eputs ("]\n");
     }
+  if (g_free > JAM_SIZE)
+    JAM_SIZE = g_free + g_free / 2;
+  memcpy (g_cells-1, g_news-1, (g_free+2)*sizeof (struct scm));
   return g_stack;
 }
 
@@ -135,9 +141,23 @@ gc_check ()
   return cell_unspecified;
 }
 
+SCM
+gc_init_news () ///((internal))
+{
+  g_news = g_cells + g_free;
+  NTYPE (0) = TVECTOR;
+  NLENGTH (0) = 1000;
+  NVECTOR (0) = 0;
+  g_news++;
+  NTYPE (0) = TCHAR;
+  NVALUE (0) = 'n';
+  return 0;
+}
+
 SCM
 gc_ () ///((internal))
 {
+  gc_init_news ();
   if (g_debug == 2)
     eputs (".");
   if (g_debug > 2)
@@ -150,9 +170,7 @@ gc_ () ///((internal))
     }
   g_free = 1;
 
-  if (g_cells < g_news
-      //&& g_free > ARENA_SIZE >> 2
-      && ARENA_SIZE < MAX_ARENA_SIZE)
+  if (ARENA_SIZE < MAX_ARENA_SIZE && (int)g_news > 0)
     {
       if (g_debug == 2)
         eputs ("+");
diff --git a/src/mes.c b/src/mes.c
index 2971a883..ec17ca63 100644
--- a/src/mes.c
+++ b/src/mes.c
@@ -25,22 +25,15 @@
 #include <mlibc.h>
 
 //#define MES_MINI 1
-
-// minimal for boot-0.scm
-// int ARENA_SIZE = 100000; // 32b: 1MiB, 64b: 2 MiB
-// take a bit more to run all tests
-// int ARENA_SIZE = 400000; // 32b: 1MiB, 64b: 2 MiB
-// take a bit extra for loading repl
-int ARENA_SIZE = 1000000; // 32b: 2MiB, 64b: 4 MiB
-#if !_POSIX_SOURCE
-//int MAX_ARENA_SIZE = 60000000; // 32b: ~ 300MiB
-int MAX_ARENA_SIZE = 166600000; // 32b: ~ 2GiB
-//int MAX_ARENA_SIZE = 500000000; // 32b: ~ 8GiB
+#if _POSIX_SOURCE
+int ARENA_SIZE = 300000000; // 32b: 4GiB, 64b: 8 GiB
 #else
-int MAX_ARENA_SIZE = 200000000; // 32b: 2.3GiB, 64b: 4.6GiB
+int ARENA_SIZE = 200000; // 32b: 2MiB, 64b: 4 MiB
 #endif
+int MAX_ARENA_SIZE = 300000000;
 
-int GC_SAFETY = 4000;
+int JAM_SIZE = 20000;
+int GC_SAFETY = 2000;
 
 char *g_arena = 0;
 typedef int SCM;
@@ -324,7 +317,6 @@ int g_function = 0;
 SCM
 alloc (int n)
 {
-  assert (g_free + n < ARENA_SIZE);
   SCM x = g_free;
   g_free += n;
   return x;
@@ -1537,7 +1529,7 @@ SCM g_symbol_max;
 SCM
 gc_init_cells () ///((internal))
 {
-  g_cells = (struct scm *)malloc (2*ARENA_SIZE*sizeof (struct scm));
+  g_cells = (struct scm *)malloc ((ARENA_SIZE+JAM_SIZE)*sizeof (struct scm));
   TYPE (0) = TVECTOR;
   LENGTH (0) = 1000;
   VECTOR (0) = 0;
@@ -1547,24 +1539,10 @@ gc_init_cells () ///((internal))
   return 0;
 }
 
-SCM
-gc_init_news () ///((internal))
-{
-  g_news = g_cells-1 + ARENA_SIZE;
-  NTYPE (0) = TVECTOR;
-  NLENGTH (0) = 1000;
-  NVECTOR (0) = 0;
-  g_news++;
-  NTYPE (0) = TCHAR;
-  NVALUE (0) = 'n';
-  return 0;
-}
-
 SCM
 mes_symbols () ///((internal))
 {
   gc_init_cells ();
-  gc_init_news ();
 
 #if MES_MINI
 
@@ -2364,6 +2342,10 @@ main (int argc, char *argv[])
     MAX_ARENA_SIZE = atoi (p);
   if (p = getenv ("MES_ARENA"))
     ARENA_SIZE = atoi (p);
+  JAM_SIZE = ARENA_SIZE / 10;
+  if (p = getenv ("MES_JAM"))
+    JAM_SIZE = atoi (p);
+  GC_SAFETY = ARENA_SIZE / 100;
   if (p = getenv ("MES_SAFETY"))
     GC_SAFETY = atoi (p);
   g_stdin = STDIN;