From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Wed, 30 Jun 2021 16:26:02 +0000 (+0200)
Subject: dnsdist: Make the Lua FFI per-thread counters atomic
X-Git-Tag: dnsdist-1.7.0-alpha1~88^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3f5e84ef2bdf1c6b22bf25dd9704e5cc0668cfbf;p=thirdparty%2Fpdns.git

dnsdist: Make the Lua FFI per-thread counters atomic

We should not actually need that since the rules and actions are
either created sequentially at configuration time or via the console
at runtime, which requires holding the global Lua lock.
Still we don't care about performance when creating these objects
so let's just use an atomic counter instead.
---

diff --git a/pdns/dnsdist-lua-actions.cc b/pdns/dnsdist-lua-actions.cc
index aadaa3c008..9acbf67b18 100644
--- a/pdns/dnsdist-lua-actions.cc
+++ b/pdns/dnsdist-lua-actions.cc
@@ -549,13 +549,13 @@ private:
     func_t d_func;
     bool d_initialized{false};
   };
-  static uint64_t s_functionsCounter;
+  static std::atomic<uint64_t> s_functionsCounter;
   static thread_local std::map<uint64_t, PerThreadState> t_perThreadStates;
   std::string d_functionCode;
   uint64_t d_functionID;
 };
 
-uint64_t LuaFFIPerThreadAction::s_functionsCounter = 0;
+std::atomic<uint64_t> LuaFFIPerThreadAction::s_functionsCounter = 0;
 thread_local std::map<uint64_t, LuaFFIPerThreadAction::PerThreadState> LuaFFIPerThreadAction::t_perThreadStates;
 
 class LuaFFIResponseAction: public DNSResponseAction
@@ -671,13 +671,13 @@ private:
     bool d_initialized{false};
   };
 
-  static uint64_t s_functionsCounter;
+  static std::atomic<uint64_t> s_functionsCounter;
   static thread_local std::map<uint64_t, PerThreadState> t_perThreadStates;
   std::string d_functionCode;
   uint64_t d_functionID;
 };
 
-uint64_t LuaFFIPerThreadResponseAction::s_functionsCounter = 0;
+std::atomic<uint64_t> LuaFFIPerThreadResponseAction::s_functionsCounter = 0;
 thread_local std::map<uint64_t, LuaFFIPerThreadResponseAction::PerThreadState> LuaFFIPerThreadResponseAction::t_perThreadStates;
 
 thread_local std::default_random_engine SpoofAction::t_randomEngine;
diff --git a/pdns/dnsdistdist/dnsdist-rules.cc b/pdns/dnsdistdist/dnsdist-rules.cc
index f1e6eece97..96666a2143 100644
--- a/pdns/dnsdistdist/dnsdist-rules.cc
+++ b/pdns/dnsdistdist/dnsdist-rules.cc
@@ -22,5 +22,5 @@
 
 #include "dnsdist-rules.hh"
 
-uint64_t LuaFFIPerThreadRule::s_functionsCounter = 0;
+std::atomic<uint64_t> LuaFFIPerThreadRule::s_functionsCounter = 0;
 thread_local std::map<uint64_t, LuaFFIPerThreadRule::PerThreadState> LuaFFIPerThreadRule::t_perThreadStates;
diff --git a/pdns/dnsdistdist/dnsdist-rules.hh b/pdns/dnsdistdist/dnsdist-rules.hh
index 2c3960df1b..1d70a80845 100644
--- a/pdns/dnsdistdist/dnsdist-rules.hh
+++ b/pdns/dnsdistdist/dnsdist-rules.hh
@@ -1228,7 +1228,7 @@ private:
     bool d_initialized{false};
   };
 
-  static uint64_t s_functionsCounter;
+  static std::atomic<uint64_t> s_functionsCounter;
   static thread_local std::map<uint64_t, PerThreadState> t_perThreadStates;
   std::string d_functionCode;
   uint64_t d_functionID;