erts: Make literal_alloc documented and configurable

Except it cannot be disabled and cannot be multi-threaded.

The bit-vector 'erts_literal_vspace_map' on 32-bit is currently only
protected by the literal allocator mutex. We could allow multiple
instances on 64-bit (I think), but what would be the point?

4 files changed, 35 insertions, 6 deletions

diff --git a/erts/doc/src/erts_alloc.xml b/erts/doc/src/erts_alloc.xml
index 15b78ffa10..75de74523e 100644
--- a/erts/doc/src/erts_alloc.xml
+++ b/erts/doc/src/erts_alloc.xml
@@ -52,6 +52,8 @@
       <item>Allocator used for ETS data.</item>
       <tag><c>driver_alloc</c></tag>
       <item>Allocator used for driver data.</item>
+      <tag><c>literal_alloc</c></tag>
+      <item>Allocator used for constant terms in Erlang code.</item>
       <tag><c>sl_alloc</c></tag>
       <item>Allocator used for memory blocks that are expected to be
        short-lived.</item>
@@ -77,7 +79,7 @@
        instead of creating new segments.  This in order to reduce
        the number of system calls made.</item>
     </taglist>
-    <p><c>sys_alloc</c> is always enabled and
+    <p><c>sys_alloc</c> and <c>literal_alloc</c> are always enabled and
       cannot be disabled. <c>mseg_alloc</c> is always enabled if it is
       available and an allocator that uses it is enabled. All other
       allocators can be <seealso marker="#M_e">enabled or disabled</seealso>.
@@ -246,6 +248,7 @@
       the currently present allocators:</p>
     <list type="bulleted">
       <item><c>B: binary_alloc</c></item>
+      <item><c>I: literal_alloc</c></item>
       <item><c>D: std_alloc</c></item>
       <item><c>E: ets_alloc</c></item>
       <item><c>F: fix_alloc</c></item>
diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index 806f569c38..14ff13fdb2 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -165,6 +165,8 @@ enum allctr_type {
 struct au_init {
     int enable;
     int thr_spec;
+    int disable_allowed;
+    int thr_spec_allowed;
     int carrier_migration_allowed;
     enum allctr_type	atype;
     struct {
@@ -217,7 +219,7 @@ typedef struct {
     struct au_init test_alloc;
 } erts_alc_hndl_args_init_t;
 
-#define ERTS_AU_INIT__ {0, 0, 1, GOODFIT, DEFAULT_ALLCTR_INIT, {1,1,1,1}}
+#define ERTS_AU_INIT__ {0, 0, 1, 1, 1, GOODFIT, DEFAULT_ALLCTR_INIT, {1,1,1,1}}
 
 #define SET_DEFAULT_ALLOC_OPTS(IP)					\
 do {									\
@@ -294,6 +296,9 @@ set_default_literal_alloc_opts(struct au_init *ip)
     SET_DEFAULT_ALLOC_OPTS(ip);
     ip->enable			= 1;
     ip->thr_spec		= 0;
+    ip->disable_allowed         = 0;
+    ip->thr_spec_allowed        = 0;
+    ip->carrier_migration_allowed = 0;
     ip->atype			= BESTFIT;
     ip->init.bf.ao		= 1;
     ip->init.util.ramv		= 0;
@@ -1352,9 +1357,17 @@ handle_au_arg(struct au_init *auip,
 	else
 	    goto bad_switch;
 	break;
-    case 'e':
-	auip->enable = get_bool_value(sub_param+1, argv, ip);
+    case 'e': {
+	int e = get_bool_value(sub_param + 1, argv, ip);
+        if (!auip->disable_allowed && !e) {
+            if (!u_switch)
+                bad_value(param, sub_param + 1, "false");
+	    else
+		ASSERT(auip->enable); /* ignore */
+        }
+	else auip->enable = e;
 	break;
+    }
     case 'l':
 	if (has_prefix("lmbcs", sub_param)) {
 	    auip->default_.lmbcs = 0;
@@ -1423,7 +1436,14 @@ handle_au_arg(struct au_init *auip,
     case 't': {
 	int res = get_bool_value(sub_param+1, argv, ip);
 	if (res > 0) {
-	    auip->thr_spec = 1;
+	    if (!auip->thr_spec_allowed) {
+		if (!u_switch)
+                    bad_value(param, sub_param + 1, "true");
+		else
+		    ASSERT(!auip->thr_spec); /* ignore */
+	    }
+	    else
+		auip->thr_spec = 1;
 	    break;
 	}
 	else if (res == 0) {
@@ -1472,6 +1492,9 @@ handle_args(int *argc, char **argv, erts_alc_hndl_args_init_t *init)
 		case 'B':
 		    handle_au_arg(&init->binary_alloc, &argv[i][3], argv, &i, 0);
 		    break;
+		case 'I':
+                    handle_au_arg(&init->literal_alloc, &argv[i][3], argv, &i, 0);
+		    break;
 		case 'D':
 		    handle_au_arg(&init->std_alloc, &argv[i][3], argv, &i, 0);
 		    break;
diff --git a/erts/emulator/sys/common/erl_mmap.h b/erts/emulator/sys/common/erl_mmap.h
index 61d912fd28..67e131b53e 100644
--- a/erts/emulator/sys/common/erl_mmap.h
+++ b/erts/emulator/sys/common/erl_mmap.h
@@ -50,8 +50,10 @@ typedef struct {
 #define ERTS_MMAP_INIT_DEFAULT_INITER \
     {{NULL, NULL}, {NULL, NULL}, 0, 1, (1 << 16), 1}
 
+#define ERTS_LITERAL_VIRTUAL_AREA_SIZE (UWORD_CONSTANT(1)*1024*1024*1024)
+
 #define ERTS_MMAP_INIT_LITERAL_INITER \
-    {{NULL, NULL}, {NULL, NULL}, 1024*1024*1024, 1, (1 << 16), 0}
+    {{NULL, NULL}, {NULL, NULL}, ERTS_LITERAL_VIRTUAL_AREA_SIZE, 1, (1 << 16), 0}
 
 typedef struct ErtsMemMapper_ ErtsMemMapper;
 
diff --git a/erts/etc/common/erlexec.c b/erts/etc/common/erlexec.c
index f21671e837..91204fda5c 100644
--- a/erts/etc/common/erlexec.c
+++ b/erts/etc/common/erlexec.c
@@ -65,6 +65,7 @@
 static const char plusM_au_allocs[]= {
     'u',	/* all alloc_util allocators */
     'B',	/* binary_alloc		*/
+    'I',	/* literal_alloc	*/
     'D',	/* std_alloc		*/
     'E',	/* ets_alloc		*/
     'F',	/* fix_alloc		*/