diff --git a/src/commands/install/protocol/resolver.cr b/src/commands/install/protocol/resolver.cr
index caf4e72..af891f6 100644
--- a/src/commands/install/protocol/resolver.cr
+++ b/src/commands/install/protocol/resolver.cr
@@ -67,7 +67,7 @@ abstract struct Zap::Commands::Install::Protocol::Resolver
       else
         packages_ref = "#{name}@#{pinned_dependency}"
       end
-      state.lockfile.packages_lock.synchronize do
+      state.lockfile.packages_lock.read do
         state.lockfile.packages[packages_ref]?
       end
     end
diff --git a/src/commands/install/resolver.cr b/src/commands/install/resolver.cr
index 750505b..dbca39b 100644
--- a/src/commands/install/resolver.cr
+++ b/src/commands/install/resolver.cr
@@ -153,7 +153,7 @@ module Zap::Commands::Install::Resolver
       lockfile_cached = uninitialized Bool
       metadata = keyed_lock(metadata_key) do
         # If another fiber has already resolved the package, use the cached metadata
-        lockfile_metadata = state.lockfile.packages_lock.synchronize do
+        lockfile_metadata = state.lockfile.packages_lock.read do
           state.lockfile.packages[metadata_key]?
         end
         lockfile_cached = !!lockfile_metadata
@@ -181,7 +181,7 @@ module Zap::Commands::Install::Resolver
           # Remove dev dependencies
           _metadata.dev_dependencies = nil
           # Store the package data in the lockfile
-          state.lockfile.packages_lock.synchronize do
+          state.lockfile.packages_lock.write do
             state.lockfile.packages[metadata_key] = _metadata
           end
         end
diff --git a/src/lockfile.cr b/src/lockfile.cr
index 9a94e3f..3431f2e 100644
--- a/src/lockfile.cr
+++ b/src/lockfile.cr
@@ -3,6 +3,7 @@ require "yaml"
 require "msgpack"
 require "digest"
 require "./utils/macros"
+require "./utils/concurrent/rwlock"
 
 alias DependencyType = ::Zap::Package::DependencyType
 
@@ -47,7 +48,7 @@ class Zap::Lockfile
   @roots_lock = Mutex.new
   @[YAML::Field(ignore: true)]
   @[MessagePack::Field(ignore: true)]
-  getter packages_lock = Mutex.new
+  getter packages_lock = Utils::Concurrent::RWLock.new
   @[YAML::Field(ignore: true)]
   @[MessagePack::Field(ignore: true)]
   property read_status : ReadStatus = ReadStatus::NotFound
diff --git a/src/utils/concurrent/rwlock.cr b/src/utils/concurrent/rwlock.cr
new file mode 100644
index 0000000..b404a8d
--- /dev/null
+++ b/src/utils/concurrent/rwlock.cr
@@ -0,0 +1,50 @@
+class Zap::Utils::Concurrent::RWLock
+  @writer = Atomic(Int32).new(0)
+  @readers = Atomic(Int32).new(0)
+
+  def read_lock
+    loop do
+      while @writer.get != 0
+        Intrinsics.pause
+      end
+
+      @readers.add(1)
+
+      break if @writer.get == 0
+
+      @readers.sub(1)
+    end
+  end
+
+  def read_unlock
+    @readers.sub(1)
+  end
+
+  def read
+    read_lock
+    yield
+  ensure
+    read_unlock
+  end
+
+  def write_lock
+    while @writer.swap(1) != 0
+      Intrinsics.pause
+    end
+
+    while @readers.get != 0
+      Intrinsics.pause
+    end
+  end
+
+  def write_unlock
+    @writer.set(0)
+  end
+
+  def write
+    write_lock
+    yield
+  ensure
+    write_unlock
+  end
+end
diff --git a/src/utils/data_structures/safe_array.cr b/src/utils/data_structures/safe_array.cr
index 69f9ba7..5d89964 100644
--- a/src/utils/data_structures/safe_array.cr
+++ b/src/utils/data_structures/safe_array.cr
@@ -1,20 +1,54 @@
 {% if flag?(:preview_mt) %}
+  require "../concurrent/rwlock"
+
   struct SafeArray(T)
     property inner : Array(T)
-    @lock = Mutex.new
+    @lock = Zap::Utils::Concurrent::RWLock.new
 
     def initialize(*args, **kwargs)
       @inner = Array(T).new(*args, **kwargs)
     end
 
-    def synchronize
-      @lock.synchronize do
-        yield @inner
+    {% begin %}
+      {% write_methods = [
+           :[]=,
+           :<<,
+           :clear,
+           :concat,
+           :compact!,
+           :delete,
+           :delete_at,
+           :fill,
+           :insert,
+           :pop,
+           :pop?,
+           :push,
+           :reject!,
+           :replace,
+           :rotate!,
+           :select!,
+           :shift,
+           :shift?,
+           :sort!,
+           :sort_by!,
+           :truncate,
+           :uniq!,
+           :unshift,
+           :unstable_sort!,
+           :unstable_sort_by!,
+         ] %}
+
+      {% for write_method in write_methods %}
+      def {{write_method.id}}(*args, **kwargs)
+        @lock.write do
+          @inner.{{write_method.id}}(*args, **kwargs)
+        end
       end
-    end
+      {% end %}
+    {% end %}
 
     macro method_missing(call)
-      @lock.synchronize do
+      @lock.read do
         @inner.\{{call}}
       end
     end
diff --git a/src/utils/data_structures/safe_hash.cr b/src/utils/data_structures/safe_hash.cr
index 7a8830e..81cd58d 100644
--- a/src/utils/data_structures/safe_hash.cr
+++ b/src/utils/data_structures/safe_hash.cr
@@ -1,9 +1,10 @@
 {% if flag?(:preview_mt) %}
   require "msgpack"
+  require "../concurrent/rwlock"
 
   struct SafeHash(K, V)
     getter inner : Hash(K, V)
-    getter lock = Mutex.new(:reentrant)
+    getter lock = Zap::Utils::Concurrent::RWLock.new
 
     def initialize(*args, **kwargs)
       @inner = Hash(K, V).new(*args, **kwargs)
@@ -13,18 +14,38 @@
       @inner = Hash(K, V).new(*args, **kwargs, &block)
     end
 
-    def synchronize
-      @lock.synchronize do
-        yield @inner
-      end
-    end
-
     def to_msgpack(packer : MessagePack::Packer)
       @inner.to_msgpack(packer)
     end
 
+    {% begin %}
+      {% write_methods = [
+           :[]=,
+           :clear,
+           :compact!,
+           :delete,
+           :merge!,
+           :put,
+           :put_if_absent,
+           :reject!,
+           :select!,
+           :shift,
+           :shift?,
+           :transform_values!,
+           :update,
+         ] %}
+
+      {% for write_method in write_methods %}
+      def {{write_method.id}}(*args, **kwargs)
+        @lock.write do
+          @inner.{{write_method.id}}(*args, **kwargs)
+        end
+      end
+      {% end %}
+    {% end %}
+
     macro method_missing(call)
-      @lock.synchronize do
+      @lock.read do
         @inner.\{{call}}
       end
     end
diff --git a/src/utils/data_structures/safe_set.cr b/src/utils/data_structures/safe_set.cr
index d18f55f..d9b78a9 100644
--- a/src/utils/data_structures/safe_set.cr
+++ b/src/utils/data_structures/safe_set.cr
@@ -1,14 +1,35 @@
 {% if flag?(:preview_mt) %}
   struct SafeSet(T)
     property inner : Set(T)
-    getter lock = Mutex.new(:reentrant)
+    getter lock = Zap::Utils::Concurrent::RWLock.new
 
     def initialize(*args, **kwargs)
       @inner = Set(T).new(*args, **kwargs)
     end
 
+   {% begin %}
+      {% write_methods = [
+           :<<,
+           :add,
+           :add?,
+           :clear,
+           :concat,
+           :delete,
+           :rehash,
+           :substract,
+         ] %}
+
+      {% for write_method in write_methods %}
+      def {{write_method.id}}(*args, **kwargs)
+        @lock.write do
+          @inner.{{write_method.id}}(*args, **kwargs)
+        end
+      end
+      {% end %}
+    {% end %}
+
     macro method_missing(call)
-      @lock.synchronize do
+      @lock.read do
         @inner.\{{call}}
       end
     end