Improve binary garbage collection

The garbage collector in r13b03 is too aggressive in some cases. This
commit raises the level of default initial allowed binary garbage
(virtual heap for binaries) before collecting from 233 words to
46368 words (181 kB on 32-bit).

A new option, min_bin_vheap_size, has been added to spawn_opt,
system_flag and process_flag can be used to change the default values.

The option can also be used with system_info and process_info to
inspect the values.

For symmetry the option min_heap_size has been added to the above
functions where it was previously missing.

Add testcases for min_bin_vheap_size and min_heap_size for
functions process_flag/2, process_info/2, system_info/2 and
spawn_opt/2.

1 files changed, 57 insertions, 5 deletions

diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 74b231d56d..a6668d5665 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -807,11 +807,12 @@ BIF_RETTYPE spawn_opt_1(BIF_ALIST_1)
     /*
      * Store default values for options.
      */
-    so.flags = SPO_USE_ARGS;
-    so.min_heap_size = H_MIN_SIZE;
-    so.priority = PRIORITY_NORMAL;
-    so.max_gen_gcs = (Uint16) erts_smp_atomic_read(&erts_max_gen_gcs);
-    so.scheduler = 0;
+    so.flags          = SPO_USE_ARGS;
+    so.min_heap_size  = H_MIN_SIZE;
+    so.min_vheap_size = BIN_VH_MIN_SIZE;
+    so.priority       = PRIORITY_NORMAL;
+    so.max_gen_gcs    = (Uint16) erts_smp_atomic_read(&erts_max_gen_gcs);
+    so.scheduler      = 0;
 
     /*
      * Walk through the option list.
@@ -850,6 +851,15 @@ BIF_RETTYPE spawn_opt_1(BIF_ALIST_1)
 		} else {
 		    so.min_heap_size = erts_next_heap_size(min_heap_size, 0);
 		}
+	    } else if (arg == am_min_bin_vheap_size && is_small(val)) {
+		Sint min_vheap_size = signed_val(val);
+		if (min_vheap_size < 0) {
+		    goto error;
+		} else if (min_vheap_size < BIN_VH_MIN_SIZE) {
+		    so.min_vheap_size = BIN_VH_MIN_SIZE;
+		} else {
+		    so.min_vheap_size = erts_next_heap_size(min_vheap_size, 0);
+		}
 	    } else if (arg == am_fullsweep_after && is_small(val)) {
 		Sint max_gen_gcs = signed_val(val);
 		if (max_gen_gcs < 0) {
@@ -1485,6 +1495,23 @@ BIF_RETTYPE process_flag_2(BIF_ALIST_2)
        }
        BIF_RET(old_value);
    }
+   else if (BIF_ARG_1 == am_min_bin_vheap_size) {
+       Sint i;
+       if (!is_small(BIF_ARG_2)) {
+	   goto error;
+       }
+       i = signed_val(BIF_ARG_2);
+       if (i < 0) {
+	   goto error;
+       }
+       old_value = make_small(BIF_P->min_vheap_size);
+       if (i < BIN_VH_MIN_SIZE) {
+	   BIF_P->min_vheap_size = BIN_VH_MIN_SIZE;
+       } else {
+	   BIF_P->min_vheap_size = erts_next_heap_size(i, 0);
+       }
+       BIF_RET(old_value);
+   }
    else if (BIF_ARG_1 == am_sensitive) {
        Uint is_sensitive;
        if (BIF_ARG_2 == am_true) {
@@ -3736,10 +3763,35 @@ BIF_RETTYPE system_flag_2(BIF_ALIST_2)
 	BIF_RET(make_small(oval));
     } else if (BIF_ARG_1 == am_min_heap_size) {
 	int oval = H_MIN_SIZE;
+
 	if (!is_small(BIF_ARG_2) || (n = signed_val(BIF_ARG_2)) < 0) {
 	    goto error;
 	}
+
+	erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
+	erts_smp_block_system(0);
+
 	H_MIN_SIZE = erts_next_heap_size(n, 0);
+
+	erts_smp_release_system();
+	erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_MAIN);
+
+	BIF_RET(make_small(oval));
+    } else if (BIF_ARG_1 == am_min_bin_vheap_size) {
+	int oval = BIN_VH_MIN_SIZE;
+
+	if (!is_small(BIF_ARG_2) || (n = signed_val(BIF_ARG_2)) < 0) {
+	    goto error;
+	}
+
+	erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
+	erts_smp_block_system(0);
+
+	BIN_VH_MIN_SIZE = erts_next_heap_size(n, 0);
+
+	erts_smp_release_system();
+	erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_MAIN);
+
 	BIF_RET(make_small(oval));
     } else if (BIF_ARG_1 == am_display_items) {
 	int oval = display_items;