vmarray_fsa.diff

diff --git a/src/6model/reprs/VMArray.c b/src/6model/reprs/VMArray.c
index b1eaf19c..1ddd68c3 100644
--- a/src/6model/reprs/VMArray.c
+++ b/src/6model/reprs/VMArray.c
@@ -92,7 +92,10 @@ static void gc_mark(MVMThreadContext *tc, MVMSTable *st, void *data, MVMGCWorkli
 /* Called by the VM in order to free memory associated with this object. */
 static void gc_free(MVMThreadContext *tc, MVMObject *obj) {
     MVMArray *arr = (MVMArray *)obj;
-    MVM_free(arr->body.slots.any);
+    if (arr->body.fsa)
+        MVM_fixed_size_free(tc, tc->instance->fsa, arr->body.ssize, arr->body.slots.any);
+    else
+        MVM_free(arr->body.slots.any);
 }
 
 /* Marks the representation data in an STable.*/
diff --git a/src/6model/reprs/VMArray.h b/src/6model/reprs/VMArray.h
index 6191356f..c96f6a5c 100644
--- a/src/6model/reprs/VMArray.h
+++ b/src/6model/reprs/VMArray.h
@@ -32,6 +32,7 @@ struct MVMArrayBody {
         void       *any;
     } slots;
 
+    MVMuint8    fsa;
 #if MVM_ARRAY_CONC_DEBUG
     AO_t in_use;
 #endif 
diff --git a/src/io/procops.c b/src/io/procops.c
index 2d0b28ba..2ed420b8 100644
--- a/src/io/procops.c
+++ b/src/io/procops.c
@@ -505,8 +505,9 @@ static void async_spawn_on_exit(uv_process_t *req, MVMint64 exit_status, int ter
 
 /* Allocates a buffer of the suggested size. */
 static void on_alloc(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
-    size_t size = suggested_size > 0 ? suggested_size : 4;
-    buf->base   = MVM_malloc(size);
+    size_t size = 1024;
+    MVMThreadContext *tc  = (MVMThreadContext *)((SpawnInfo *)handle->data)->tc;
+    buf->base   = MVM_fixed_size_alloc(tc, tc->instance->fsa, size);
     buf->len    = size;
 }
 
@@ -534,6 +535,7 @@ static void async_read(uv_stream_t *handle, ssize_t nread, const uv_buf_t *buf,
                 MVMObject *buf_type    = MVM_repr_at_key_o(tc, si->callbacks,
                                             tc->instance->str_consts.buf_type);
                 MVMArray  *res_buf     = (MVMArray *)MVM_repr_alloc_init(tc, buf_type);
+                res_buf->body.fsa      = 1;
                 res_buf->body.slots.i8 = (MVMint8 *)buf->base;
                 res_buf->body.start    = 0;
                 res_buf->body.ssize    = buf->len;
@@ -571,7 +573,7 @@ static void async_read(uv_stream_t *handle, ssize_t nread, const uv_buf_t *buf,
         });
         });
         if (buf->base)
-            MVM_free(buf->base);
+            MVM_fixed_size_free(tc, tc->instance->fsa, buf->len, buf->base);
         uv_close((uv_handle_t *)handle, NULL);
         if (--si->using == 0)
             MVM_io_eventloop_remove_active_work(tc, &(si->work_idx));
@@ -589,7 +591,7 @@ static void async_read(uv_stream_t *handle, ssize_t nread, const uv_buf_t *buf,
         });
         });
         if (buf->base)
-            MVM_free(buf->base);
+            MVM_fixed_size_free(tc, tc->instance->fsa, buf->len, buf->base);
         uv_close((uv_handle_t *)handle, NULL);
         if (--si->using == 0)
             MVM_io_eventloop_remove_active_work(tc, &(si->work_idx));