Replace the +MMscmgc switch with +MMscrfsd

Replaced the +MMscmgc switch with the +MMscrfsd switch. The old switch
didn't reflect what it controlled.

6 files changed, 31 insertions, 27 deletions

diff --git a/erts/doc/src/erts_alloc.xml b/erts/doc/src/erts_alloc.xml
index 70029dbeab..8f5e8cd10b 100644
--- a/erts/doc/src/erts_alloc.xml
+++ b/erts/doc/src/erts_alloc.xml
@@ -271,15 +271,6 @@
        memory segment cache is not reused if its size exceeds the
        requested size with more than relative max cache bad fit
        percent of the requested size. Default value is 20.</item>
-      <tag><marker id="MMscmgc"><c><![CDATA[+MMscmgc <amount>]]></c></marker></tag>
-      <item>
-	Set <seealso marker="#MMscs">super carrier</seealso> max guaranteed
-	no of carriers. This parameter defaults to <c>65536</c>. This
-	parameter determines an amount of pre-allocated structures that is
-	needed in order to keep track of different areas in the super carrier.
-	When the system runs out of such structures it may crash due to an
-	out of memory condition.
-      </item>
       <tag><marker id="MMsco"><c><![CDATA[+MMsco true|false]]></c></marker></tag>
       <item>
 	Set <seealso marker="#MMscs">super carrier</seealso> only flag. This
@@ -295,6 +286,19 @@
 	disabled on halfword heap systems. This flag will be
 	ignored on halfword heap systems.
       </item>
+      <tag><marker id="MMscrfsd"><c><![CDATA[+MMscrfsd <amount>]]></c></marker></tag>
+      <item>
+	Set <seealso marker="#MMscs">super carrier</seealso> reserved
+	free segment descriptors. This parameter defaults to <c>65536</c>.
+	This parameter determines the amount of memory to reserve for
+	free segment descriptors used by the super carrier. If the system
+	runs out of reserved memory for free segment descriptors, other
+	memory will be used. This may however cause fragmentation issues,
+	so you want to ensure that this	never happens. The maximum amount
+	of free segment descriptors used can be retrieved from the
+	<c>erts_mmap</c> tuple part of the result from calling
+	<seealso marker="erts:erlang#system_info_allocator_tuple">erlang:system_info({allocator, mseg_alloc})</seealso>.
+      </item>
       <tag><marker id="MMscrpm"><c><![CDATA[+MMscrpm true|false]]></c></marker></tag>
       <item>
 	Set <seealso marker="#MMscs">super carrier</seealso> reserve physical
diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index fb0f47d1b7..b5ba9bb94a 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -1504,11 +1504,11 @@ handle_args(int *argc, char **argv, erts_alc_hndl_args_init_t *init)
 #endif
 			    get_bool_value(argv[i]+8, argv, &i);
 		    }
-		    else if (has_prefix("scmgc", argv[i]+3)) {
+		    else if (has_prefix("scrfsd", argv[i]+3)) {
 #if HAVE_ERTS_MSEG
-			init->mseg.mmap.scmgc =
+			init->mseg.mmap.scrfsd =
 #endif
-			    get_amount_value(argv[i]+8, argv, &i);
+			    get_amount_value(argv[i]+9, argv, &i);
 		    }
 		    else {
 			bad_param(param, param+2);
diff --git a/erts/emulator/sys/common/erl_mmap.c b/erts/emulator/sys/common/erl_mmap.c
index a9da7430fb..3f6813e1a5 100644
--- a/erts/emulator/sys/common/erl_mmap.c
+++ b/erts/emulator/sys/common/erl_mmap.c
@@ -2057,7 +2057,7 @@ static struct {
     Eterm scs;
     Eterm sco;
     Eterm scrpm;
-    Eterm scmgc;
+    Eterm scrfsd;
 
     int is_initialized;
     erts_mtx_t init_mutex;
@@ -2090,7 +2090,7 @@ static void init_atoms(void)
         AM_INIT(scs);
         AM_INIT(sco);
         AM_INIT(scrpm);
-        AM_INIT(scmgc);
+        AM_INIT(scrfsd);
         am.is_initialized = 1;
     }
     erts_mtx_unlock(&am.init_mutex);
@@ -2121,7 +2121,7 @@ erts_mmap_init(ErtsMMapInit *init)
 #if defined(HARD_DEBUG)  || 0
     erts_fprintf(stderr, "erts_mmap: scs = %bpu\n", init->scs);
     erts_fprintf(stderr, "erts_mmap: sco = %i\n", init->sco);
-    erts_fprintf(stderr, "erts_mmap: scmgc = %i\n", init->scmgc);
+    erts_fprintf(stderr, "erts_mmap: scrfsd = %i\n", init->scrfsd);
 #endif
     erts_page_inv_mask = pagesize - 1;
     if (pagesize & erts_page_inv_mask)
@@ -2234,7 +2234,7 @@ erts_mmap_init(ErtsMMapInit *init)
 
 	mmap_state.no_os_mmap = init->sco;
 
-	desc_size = init->scmgc;
+	desc_size = init->scrfsd;
 	if (desc_size < 100)
 	    desc_size = 100;
 	desc_size *= sizeof(ErtsFreeSegDesc);
@@ -2418,7 +2418,7 @@ Eterm erts_mmap_info_options(char *prefix,
         if (mmap_state.supercarrier) {
             erts_print(to, arg, "%ssco: %T\n", prefix, sco);
             erts_print(to, arg, "%sscrpm: %T\n", prefix, scrpm);
-            erts_print(to, arg, "%sscmgc: %beu\n", prefix, mmap_state.desc.reserved);
+            erts_print(to, arg, "%sscrfsd: %beu\n", prefix, mmap_state.desc.reserved);
         }
     }
 
@@ -2429,7 +2429,7 @@ Eterm erts_mmap_info_options(char *prefix,
 
         res = NIL;
         if (mmap_state.supercarrier) {
-            add_2tup(hpp, szp, &res, am.scmgc,
+            add_2tup(hpp, szp, &res, am.scrfsd,
                      erts_bld_uint(hpp,szp, mmap_state.desc.reserved));
             add_2tup(hpp, szp, &res, am.scrpm, scrpm);
             add_2tup(hpp, szp, &res, am.sco, sco);
diff --git a/erts/emulator/sys/common/erl_mmap.h b/erts/emulator/sys/common/erl_mmap.h
index e6934dbb26..778a8e0e80 100644
--- a/erts/emulator/sys/common/erl_mmap.h
+++ b/erts/emulator/sys/common/erl_mmap.h
@@ -45,8 +45,8 @@ typedef struct {
     } predefined_area;
     UWord scs;  /* super carrier size */
     int sco;    /* super carrier only? */
-    Uint scmgc; /* super carrier: max guaranteed (number of) carriers */
-    int scrpm;
+    UWord scrfsd; /* super carrier reserved free segment descriptors */
+    int scrpm; /* super carrier reserve physical memory */
 }ErtsMMapInit;
 
 #define ERTS_MMAP_INIT_DEFAULT_INITER \
diff --git a/erts/emulator/test/alloc_SUITE.erl b/erts/emulator/test/alloc_SUITE.erl
index f6ff6bb813..cd2d043f7e 100644
--- a/erts/emulator/test/alloc_SUITE.erl
+++ b/erts/emulator/test/alloc_SUITE.erl
@@ -114,8 +114,8 @@ cpool(Cfg) -> ?line drv_case(Cfg).
 erts_mmap(Config) when is_list(Config) ->
     case {?t:os_type(), is_halfword_vm()} of
 	{{unix, _}, false} ->
-	    [erts_mmap_do(Config, SCO, SCRPM, SCMGC)
-	     || SCO <-[true,false], SCMGC <-[1234,0], SCRPM <- [true,false]];
+	    [erts_mmap_do(Config, SCO, SCRPM, SCRFSD)
+	     || SCO <-[true,false], SCRFSD <-[1234,0], SCRPM <- [true,false]];
 
 	{_,true} ->
 	    {skipped, "No supercarrier support on halfword vm"};
@@ -126,14 +126,14 @@ erts_mmap(Config) when is_list(Config) ->
     end.
 
 
-erts_mmap_do(Config, SCO, SCRPM, SCMGC) ->
+erts_mmap_do(Config, SCO, SCRPM, SCRFSD) ->
     SCS = 100, % Mb
     O1 = "+MMscs" ++ integer_to_list(SCS)
 	++ " +MMsco" ++ atom_to_list(SCO)
 	++ " +MMscrpm" ++ atom_to_list(SCRPM),
-    Opts = case SCMGC of
+    Opts = case SCRFSD of
 	       0 -> O1;
-	       _ -> O1 ++ " +MMscmgc"++integer_to_list(SCMGC)
+	       _ -> O1 ++ " +MMscrfsd"++integer_to_list(SCRFSD)
 	   end,
     {ok, Node} = start_node(Config, Opts),
     Self = self(),
@@ -148,7 +148,7 @@ erts_mmap_do(Config, SCO, SCRPM, SCMGC) ->
 		Total = SCS*1024*1024,
 
 		{reserved,Reserved} = lists:keyfind(reserved,1,Segs),
-		true = (Reserved >= SCMGC),
+		true = (Reserved >= SCRFSD),
 
 		case {SCO,lists:keyfind(os,1,EM)} of
 		    {true, false} -> ok;
diff --git a/erts/etc/common/erlexec.c b/erts/etc/common/erlexec.c
index 6fd3dd83e2..f098e56a2e 100644
--- a/erts/etc/common/erlexec.c
+++ b/erts/etc/common/erlexec.c
@@ -112,7 +112,7 @@ static char *plusM_other_switches[] = {
     "Mrmcbf",
     "Mmcs",
     "Mscs",
-    "Mscmgc",
+    "Mscrfsd",
     "Msco",
     "Mscrpm",
     "Ye",