add mimalloc allocator based on mimalloc

Author: nikneym

src/browser/mimalloc.zig

@@ -62,8 +62,8 @@ pub fn getRSS() i64 {
     const data = writer.written();
     const index = std.mem.indexOf(u8, data, "rss: ") orelse return -1;
     const sep = std.mem.indexOfScalarPos(u8, data, index + 5, ' ') orelse return -2;
-    const value = std.fmt.parseFloat(f64, data[index+5..sep]) catch return -3;
-    const unit = data[sep+1..];
+    const value = std.fmt.parseFloat(f64, data[index + 5 .. sep]) catch return -3;
+    const unit = data[sep + 1 ..];
     if (std.mem.startsWith(u8, unit, "KiB,")) {
         return @as(i64, @intFromFloat(value)) * 1024;
     }
@@ -108,3 +108,36 @@ pub export fn strn_dup(s: [*c]const u8, size: usize) callconv(.c) [*c]u8 {
 pub export fn f_ree(_: ?*anyopaque) callconv(.c) void {
     return;
 }
+
+/// An allocator that use mimalloc to manage memory.
+pub const allocator = std.mem.Allocator{
+    .ptr = undefined,
+    .vtable = Allocator.vtable,
+};
+
+const Allocator = struct {
+    fn alloc(_: *anyopaque, len: usize, alignment: std.mem.Alignment, _: usize) ?[*]u8 {
+        const ptr = c.mi_malloc_aligned(len, alignment.toByteUnits());
+        return @ptrCast(ptr);
+    }
+
+    fn resize(_: *anyopaque, memory: []u8, _: std.mem.Alignment, new_len: usize, _: usize) bool {
+        return c.mi_expand(memory.ptr, new_len) != null;
+    }
+
+    fn remap(_: *anyopaque, memory: []u8, alignment: std.mem.Alignment, new_len: usize, _: usize) ?[*]u8 {
+        const ptr = c.mi_realloc_aligned(memory.ptr, new_len, alignment.toByteUnits());
+        return @ptrCast(ptr);
+    }
+
+    fn free(_: *anyopaque, memory: []u8, alignment: std.mem.Alignment, _: usize) void {
+        c.mi_free_size_aligned(memory.ptr, memory.len, alignment.toByteUnits());
+    }
+
+    pub const vtable = &std.mem.Allocator.VTable{
+        .alloc = Allocator.alloc,
+        .resize = Allocator.resize,
+        .remap = Allocator.remap,
+        .free = Allocator.free,
+    };
+};

src/main.zig

@@ -25,6 +25,7 @@ const App = @import("app.zig").App;
 const Server = @import("server.zig").Server;
 const Browser = @import("browser/browser.zig").Browser;
 const DumpStripMode = @import("browser/dump.zig").Opts.StripMode;
+const mimalloc = @import("browser/mimalloc.zig");
 
 const build_config = @import("build_config");
 
@@ -34,9 +35,9 @@ var _server: ?Server = null;
 pub fn main() !void {
     // allocator
     // - in Debug mode we use the General Purpose Allocator to detect memory leaks
-    // - in Release mode we use the c allocator
+    // - in Release mode we use the mimalloc allocator
     var gpa: std.heap.DebugAllocator(.{}) = .init;
-    const alloc = if (builtin.mode == .Debug) gpa.allocator() else std.heap.c_allocator;
+    const alloc = if (builtin.mode == .Debug) gpa.allocator() else mimalloc.allocator;
 
     defer if (builtin.mode == .Debug) {
         if (gpa.detectLeaks()) std.posix.exit(1);