avoid over-allocation of brk on first malloc

if init_malloc returns positive (successful first init), malloc will
retry getting a chunk from the free bins rather than expanding the
heap again. also pass init_malloc a hint for the size of the initial
allocation.

diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index a4eefda..ee6f170 100644 (file)
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -179,7 +179,7 @@ fail:
        return 0;
 }
 
-static int init_malloc()
+static int init_malloc(size_t n)
 {
        static int init, waiters;
        int state;
@@ -196,7 +196,7 @@ static int init_malloc()
 
        mal.brk = __brk(0) + 2*SIZE_ALIGN-1 & -SIZE_ALIGN;
 
-       c = expand_heap(1);
+       c = expand_heap(n);
 
        if (!c) {
                a_store(&init, 0);
@@ -210,7 +210,7 @@ static int init_malloc()
 
        a_store(&init, 2);
        if (waiters) __wake(&init, -1, 1);
-       return 0;
+       return 1;
 }
 
 static int adjust_size(size_t *n)
@@ -347,7 +347,7 @@ void *malloc(size_t n)
        for (;;) {
                uint64_t mask = mal.binmap & -(1ULL<<i);
                if (!mask) {
-                       init_malloc();
+                       if (init_malloc(n) > 0) continue;
                        c = expand_heap(n);
                        if (!c) return 0;
                        if (alloc_rev(c)) {