From 245860ecaf8b9e82ca577385abd453ac92ffcd26 Mon Sep 17 00:00:00 2001
From: Justus Winter <justus@g10code.com>
Date: Thu, 20 Apr 2017 15:04:52 +0200
Subject: [PATCH] gpgscm: Avoid fruitless garbage collection cycles.

* tests/gpgscm/scheme-private.h (CELL_MINRECOVER): New macro.
* tests/gpgscm/scheme.c (_get_cell): Move the heuristic to get more
cells...
(gc): ... here where every caller benefits from the optimization.

Signed-off-by: Justus Winter <justus@g10code.com>
---
 tests/gpgscm/scheme-private.h |  7 +++++++
 tests/gpgscm/scheme.c         | 16 ++++++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/tests/gpgscm/scheme-private.h b/tests/gpgscm/scheme-private.h
index 075dc70e9..bc0269ad2 100644
--- a/tests/gpgscm/scheme-private.h
+++ b/tests/gpgscm/scheme-private.h
@@ -108,6 +108,13 @@ int tracing;
 #ifndef CELL_SEGSIZE
 #define CELL_SEGSIZE    5000  /* # of cells in one segment */
 #endif
+
+/* If less than # of cells are recovered in a garbage collector run,
+ * allocate a new cell segment to avoid fruitless collection cycles in
+ * the near future.  */
+#ifndef CELL_MINRECOVER
+#define CELL_MINRECOVER    (CELL_SEGSIZE >> 2)
+#endif
 struct cell_segment *cell_segments;
 
 /* We use 4 registers. */
diff --git a/tests/gpgscm/scheme.c b/tests/gpgscm/scheme.c
index 933dc4552..11f6fcb0c 100644
--- a/tests/gpgscm/scheme.c
+++ b/tests/gpgscm/scheme.c
@@ -949,15 +949,10 @@ static pointer _get_cell(scheme *sc, pointer a, pointer b) {
 
   assert (gc_enabled (sc));
   if (sc->free_cell == sc->NIL) {
-    const int min_to_be_recovered = CELL_SEGSIZE / 4;
     gc(sc,a, b);
-    if (sc->fcells < min_to_be_recovered
-        || sc->free_cell == sc->NIL) {
-      /* if only a few recovered, get more to avoid fruitless gc's */
-      if (!alloc_cellseg(sc,1) && sc->free_cell == sc->NIL) {
-        sc->no_memory=1;
-        return sc->sink;
-      }
+    if (sc->free_cell == sc->NIL) {
+	 sc->no_memory=1;
+	 return sc->sink;
     }
   }
   x = sc->free_cell;
@@ -1746,6 +1741,11 @@ static void gc(scheme *sc, pointer a, pointer b) {
     snprintf(msg,80,"done: %ld cells were recovered.\n", sc->fcells);
     putstr(sc,msg);
   }
+
+  /* if only a few recovered, get more to avoid fruitless gc's */
+  if (sc->fcells < CELL_MINRECOVER
+       && alloc_cellseg(sc, 1) == 0)
+       sc->no_memory = 1;
 }
 
 static void finalize_cell(scheme *sc, pointer a) {