diff --git a/lib/std/heap/PageAllocator.zig b/lib/std/heap/PageAllocator.zig
index 4ca3ec944f..bed9be5449 100644
--- a/lib/std/heap/PageAllocator.zig
+++ b/lib/std/heap/PageAllocator.zig
@@ -1,19 +1,17 @@
-const std = @import("../std.zig");
 const builtin = @import("builtin");
+const native_os = builtin.os.tag;
+
+const std = @import("../std.zig");
 const Allocator = std.mem.Allocator;
+const Alignment = std.mem.Alignment;
 const mem = std.mem;
 const maxInt = std.math.maxInt;
 const assert = std.debug.assert;
-const native_os = builtin.os.tag;
 const windows = std.os.windows;
-const ntdll = windows.ntdll;
+const ntdll = std.os.windows.ntdll;
 const posix = std.posix;
 const page_size_min = std.heap.page_size_min;
 
-const SUCCESS = @import("../os/windows/ntstatus.zig").NTSTATUS.SUCCESS;
-const MEM_RESERVE_PLACEHOLDER = windows.MEM_RESERVE_PLACEHOLDER;
-const MEM_PRESERVE_PLACEHOLDER = windows.MEM_PRESERVE_PLACEHOLDER;
-
 pub const vtable: Allocator.VTable = .{
     .alloc = alloc,
     .resize = resize,
@@ -21,7 +19,7 @@ pub const vtable: Allocator.VTable = .{
     .free = free,
 };
 
-pub fn map(n: usize, alignment: mem.Alignment) ?[*]u8 {
+pub fn map(n: usize, alignment: Alignment) ?[*]u8 {
     const page_size = std.heap.pageSize();
     if (n >= maxInt(usize) - page_size) return null;
     const alignment_bytes = alignment.toByteUnits();
@@ -33,11 +31,11 @@ pub fn map(n: usize, alignment: mem.Alignment) ?[*]u8 {
         const current_process = windows.GetCurrentProcess();
         var status = ntdll.NtAllocateVirtualMemory(current_process, @ptrCast(&base_addr), 0, &size, .{ .COMMIT = true, .RESERVE = true }, .{ .READWRITE = true });
 
-        if (status == SUCCESS and mem.isAligned(@intFromPtr(base_addr), alignment_bytes)) {
+        if (status == .SUCCESS and mem.isAligned(@intFromPtr(base_addr), alignment_bytes)) {
             return @ptrCast(base_addr);
         }
 
-        if (status == SUCCESS) {
+        if (status == .SUCCESS) {
             var region_size: windows.SIZE_T = 0;
             _ = ntdll.NtFreeVirtualMemory(current_process, @ptrCast(&base_addr), &region_size, .{ .RELEASE = true });
         }
@@ -50,7 +48,7 @@ pub fn map(n: usize, alignment: mem.Alignment) ?[*]u8 {
 
         status = ntdll.NtAllocateVirtualMemory(current_process, @ptrCast(&base_addr), 0, &size, .{ .RESERVE = true, .RESERVE_PLACEHOLDER = true }, .{ .NOACCESS = true });
 
-        if (status != SUCCESS) return null;
+        if (status != .SUCCESS) return null;
 
         const placeholder_addr = @intFromPtr(base_addr);
         const aligned_addr = mem.alignForward(usize, placeholder_addr, alignment_bytes);
@@ -75,7 +73,7 @@ pub fn map(n: usize, alignment: mem.Alignment) ?[*]u8 {
 
         status = ntdll.NtAllocateVirtualMemory(current_process, @ptrCast(&base_addr), 0, &size, .{ .COMMIT = true }, .{ .READWRITE = true });
 
-        if (status == SUCCESS) {
+        if (status == .SUCCESS) {
             return @ptrCast(base_addr);
         }
 
@@ -116,31 +114,29 @@ pub fn map(n: usize, alignment: mem.Alignment) ?[*]u8 {
     return result_ptr;
 }
 
-fn alloc(context: *anyopaque, n: usize, alignment: mem.Alignment, ra: usize) ?[*]u8 {
+fn alloc(context: *anyopaque, n: usize, alignment: Alignment, ra: usize) ?[*]u8 {
     _ = context;
     _ = ra;
     assert(n > 0);
     return map(n, alignment);
 }
 
-fn resize(context: *anyopaque, memory: []u8, alignment: mem.Alignment, new_len: usize, return_address: usize) bool {
+fn resize(context: *anyopaque, memory: []u8, alignment: Alignment, new_len: usize, return_address: usize) bool {
     _ = context;
-    _ = alignment;
     _ = return_address;
-    return realloc(memory, new_len, false) != null;
+    return realloc(memory, alignment, new_len, false) != null;
 }
 
-fn remap(context: *anyopaque, memory: []u8, alignment: mem.Alignment, new_len: usize, return_address: usize) ?[*]u8 {
+fn remap(context: *anyopaque, memory: []u8, alignment: Alignment, new_len: usize, return_address: usize) ?[*]u8 {
     _ = context;
-    _ = alignment;
     _ = return_address;
-    return realloc(memory, new_len, true);
+    return realloc(memory, alignment, new_len, true);
 }
 
-fn free(context: *anyopaque, memory: []u8, alignment: mem.Alignment, return_address: usize) void {
+fn free(context: *anyopaque, memory: []u8, alignment: Alignment, return_address: usize) void {
     _ = context;
-    _ = alignment;
     _ = return_address;
+    _ = alignment;
     return unmap(@alignCast(memory));
 }
 
@@ -155,9 +151,10 @@ pub fn unmap(memory: []align(page_size_min) u8) void {
     }
 }
 
-pub fn realloc(uncasted_memory: []u8, new_len: usize, may_move: bool) ?[*]u8 {
+pub fn realloc(uncasted_memory: []u8, alignment: Alignment, new_len: usize, may_move: bool) ?[*]u8 {
     const memory: []align(page_size_min) u8 = @alignCast(uncasted_memory);
     const page_size = std.heap.pageSize();
+    if (alignment.toByteUnits() > page_size) return null;
     const new_size_aligned = mem.alignForward(usize, new_len, page_size);
 
     if (native_os == .windows) {
diff --git a/lib/std/heap/SmpAllocator.zig b/lib/std/heap/SmpAllocator.zig
index e51e4975b6..50380d29b5 100644
--- a/lib/std/heap/SmpAllocator.zig
+++ b/lib/std/heap/SmpAllocator.zig
@@ -179,7 +179,7 @@ fn resize(context: *anyopaque, memory: []u8, alignment: mem.Alignment, new_len:
     const new_class = sizeClassIndex(new_len, alignment);
     if (class >= size_class_count) {
         if (new_class < size_class_count) return false;
-        return PageAllocator.realloc(memory, new_len, false) != null;
+        return PageAllocator.realloc(memory, alignment, new_len, false) != null;
     }
     return new_class == class;
 }
@@ -191,7 +191,7 @@ fn remap(context: *anyopaque, memory: []u8, alignment: mem.Alignment, new_len: u
     const new_class = sizeClassIndex(new_len, alignment);
     if (class >= size_class_count) {
         if (new_class < size_class_count) return null;
-        return PageAllocator.realloc(memory, new_len, true);
+        return PageAllocator.realloc(memory, alignment, new_len, true);
     }
     return if (new_class == class) memory.ptr else null;
 }