unix: Option to evenly split GC heap size over multiple heaps.

rknegjens · rknegjens · commit 691fca8bca8d · 2022-04-21T12:58:08.000-07:00
When multiple GC heaps are enabled for the unix port, the value of the C
macro MICROPY_GC_N_HEAPS determines over how many heaps the requested
heap size is divided. The coverage variant sets this to 4 to cover the
`gc_add()` function and test the multiple heaps feature. The default
is 1.
diff --git a/ports/unix/main.c b/ports/unix/main.c
@@ -464,8 +464,22 @@ MP_NOINLINE int main_(int argc, char **argv) {
     pre_process_options(argc, argv);
 
     #if MICROPY_ENABLE_GC
+    #if !MICROPY_GC_MULTIHEAP
     char *heap = malloc(heap_size);
     gc_init(heap, heap + heap_size);
+    #else
+    assert(MICROPY_GC_N_HEAPS > 0);
+    char *heaps[MICROPY_GC_N_HEAPS];
+    long multi_heap_size = heap_size / MICROPY_GC_N_HEAPS;
+    for (size_t i = 0; i < MICROPY_GC_N_HEAPS; i++) {
+        heaps[i] = malloc(multi_heap_size);
+        if (i == 0) {
+            gc_init(heaps[i], heaps[i] + multi_heap_size);
+        } else {
+            gc_add(heaps[i], heaps[i] + multi_heap_size);
+        }
+    }
+    #endif
     #endif
 
     #if MICROPY_ENABLE_PYSTACK
@@ -716,7 +730,13 @@ MP_NOINLINE int main_(int argc, char **argv) {
     #if MICROPY_ENABLE_GC && !defined(NDEBUG)
     // We don't really need to free memory since we are about to exit the
     // process, but doing so helps to find memory leaks.
+    #if !MICROPY_GC_MULTIHEAP
     free(heap);
+    #else
+    for (size_t i = 0; i < MICROPY_GC_N_HEAPS; i++) {
+        free(heaps[i]);
+    }
+    #endif
     #endif
 
     // printf("total bytes = %d\n", m_get_total_bytes_allocated());
diff --git a/ports/unix/mpconfigport.h b/ports/unix/mpconfigport.h
@@ -120,6 +120,10 @@
     #define MICROPY_EMIT_ARM        (1)
 #endif
 #define MICROPY_ENABLE_GC           (1)
+// Number of heaps to assign if MICROPY_GC_MULTIHEAP=1
+#ifndef MICROPY_GC_N_HEAPS
+#define MICROPY_GC_N_HEAPS          (1)
+#endif
 #define MICROPY_MALLOC_USES_ALLOCATED_SIZE (1)
 #define MICROPY_MEM_STATS           (1)
 #define MICROPY_DEBUG_PRINTERS      (1)
diff --git a/ports/unix/variants/coverage/mpconfigvariant.h b/ports/unix/variants/coverage/mpconfigvariant.h
@@ -56,4 +56,5 @@
 #define MICROPY_PY_UCRYPTOLIB          (1)
 #define MICROPY_PY_UCRYPTOLIB_CTR      (1)
 #define MICROPY_PY_MICROPYTHON_HEAP_LOCKED (1)
-#define MICROPY_GC_MULTIHEAP (1)
+#define MICROPY_GC_MULTIHEAP           (1)
+#define MICROPY_GC_N_HEAPS             (4)
diff --git a/py/gc.h b/py/gc.h
@@ -30,6 +30,8 @@
 #include <stddef.h>
 
 void gc_init(void *start, void *end);
+
+// Used to add additional heaps when multiple heaps are enabled.
 void gc_add(void *start, void *end);
 
 // These lock/unlock functions can be nested.
