Add MT-safe variable_cache, use for variable overrides

1 files changed, 5 insertions, 1 deletions

diff --git a/build2/b.cxx b/build2/b.cxx
index 14258b3..01d9378 100644
--- a/build2/b.cxx
+++ b/build2/b.cxx
@@ -273,7 +273,7 @@ main (int argc, char* argv[])
 
     keep_going = !ops.serial_stop ();
 
-    // Start up the scheduler.
+    // Start up the scheduler and allocate lock shards.
     //
     size_t jobs (0);
 
@@ -296,6 +296,10 @@ main (int argc, char* argv[])
 
     sched.startup (jobs);
 
+    variable_cache_mutex_shard_size = sched.shard_size ();
+    variable_cache_mutex_shard.reset (
+      new shared_mutex[variable_cache_mutex_shard_size]);
+
     // Trace some overall environment information.
     //
     if (verb >= 5)