Only enlarge heap when necessary

rust/src/bin/genpkts.rs

@@ -55,6 +55,7 @@ impl provider::Provider for Provider {
 // IMPORTANT: Must define main() like this
 #[no_mangle]
 pub fn main() {
+    enlarge_heap();
     println!("I am going to map IXGBE driver to user space");
     println!("Kernel network stack should not use it anymore");
     let addr = sys_map_pci_device(0x8086, 0x10fb);

rust/src/bin/iperf.rs

@@ -142,6 +142,7 @@ enum State {
 // IMPORTANT: Must define main() like this
 #[no_mangle]
 pub fn main() {
+    enlarge_heap();
     println!("I am going to map IXGBE driver to user space");
     println!("Kernel network stack should not use it anymore");
     let addr = sys_map_pci_device(0x8086, 0x10fb);

rust/src/lang_items.rs

@@ -12,9 +12,9 @@ fn main() {
 }
 
 fn init_heap() {
-    const HEAP_SIZE: usize = 16 * 1024 * 1024;
+    const HEAP_SIZE: usize = 0x1000;
-    let addr = sys_mmap(0, HEAP_SIZE, 0x3, 0x22, 0, 0) as usize;
+    static mut HEAP: [u8; HEAP_SIZE] = [0; HEAP_SIZE];
-    unsafe { ALLOCATOR.lock().init(addr, HEAP_SIZE); }
+    unsafe { ALLOCATOR.lock().init(HEAP.as_ptr() as usize, HEAP_SIZE); }
 }
 
 #[no_mangle]

rust/src/syscall.rs

@@ -1,3 +1,5 @@
+use crate::ALLOCATOR;
+
 #[inline(always)]
 fn sys_call(syscall_id: SyscallId, arg0: usize, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) -> i32 {
     let id = syscall_id as usize;
@@ -32,6 +34,12 @@ fn sys_call(syscall_id: SyscallId, arg0: usize, arg1: usize, arg2: usize, arg3:
     ret
 }
 
+pub fn enlarge_heap() {
+    const HEAP_SIZE: usize = 16 * 1024 * 1024;
+    let addr = sys_mmap(0, HEAP_SIZE, 0x3, 0x22, 0, 0) as usize;
+    unsafe { ALLOCATOR.lock().init(addr, HEAP_SIZE); }
+}
+
 pub fn sys_exit(code: usize) -> ! {
     sys_call(SyscallId::Exit, code, 0, 0, 0, 0, 0);
     unreachable!()