Kernel: Avoid unnecessary allocations in NetworkAdapter::for_each

This avoids allocations for initializing the Function<T>
for the NetworkAdapter::for_each callback argument.

Applying this patch decreases CPU utilization for NetworkTask
from 40% to 28% when receiving TCP packets at a rate of 100Mbit/s.

2 files changed, 11 insertions, 9 deletions

diff --git a/Kernel/Net/NetworkAdapter.cpp b/Kernel/Net/NetworkAdapter.cpp
index 379a740cc8..e050fcc581 100644
--- a/Kernel/Net/NetworkAdapter.cpp
+++ b/Kernel/Net/NetworkAdapter.cpp
@@ -21,18 +21,11 @@ namespace Kernel {
 
 static AK::Singleton<Lockable<HashTable<NetworkAdapter*>>> s_table;
 
-static Lockable<HashTable<NetworkAdapter*>>& all_adapters()
+Lockable<HashTable<NetworkAdapter*>>& NetworkAdapter::all_adapters()
 {
     return *s_table;
 }
 
-void NetworkAdapter::for_each(Function<void(NetworkAdapter&)> callback)
-{
-    Locker locker(all_adapters().lock());
-    for (auto& it : all_adapters().resource())
-        callback(*it);
-}
-
 RefPtr<NetworkAdapter> NetworkAdapter::from_ipv4_address(const IPv4Address& address)
 {
     Locker locker(all_adapters().lock());
diff --git a/Kernel/Net/NetworkAdapter.h b/Kernel/Net/NetworkAdapter.h
index 6e6dcf32b0..d25d3a2c30 100644
--- a/Kernel/Net/NetworkAdapter.h
+++ b/Kernel/Net/NetworkAdapter.h
@@ -25,7 +25,14 @@ class NetworkAdapter;
 
 class NetworkAdapter : public RefCounted<NetworkAdapter> {
 public:
-    static void for_each(Function<void(NetworkAdapter&)>);
+    template<typename Callback>
+    static inline void for_each(Callback callback)
+    {
+        Locker locker(all_adapters().lock());
+        for (auto& it : all_adapters().resource())
+            callback(*it);
+    }
+
     static RefPtr<NetworkAdapter> from_ipv4_address(const IPv4Address&);
     static RefPtr<NetworkAdapter> lookup_by_name(const StringView&);
     virtual ~NetworkAdapter();
@@ -70,6 +77,8 @@ protected:
     void did_receive(ReadonlyBytes);
 
 private:
+    static Lockable<HashTable<NetworkAdapter*>>& all_adapters();
+
     MACAddress m_mac_address;
     IPv4Address m_ipv4_address;
     IPv4Address m_ipv4_netmask;