Use max_builds instead of a lock (#734)

Co-authored-by: Zachary Ware <zach@python.org>

Author: encukou

master/custom/workers.py

@@ -30,7 +30,7 @@ def __init__(
         tags=None,
         branches=None,
         not_branches=None,
-        parallel_builders=None,
+        parallel_builders=1,
         parallel_tests=None,
         timeout_factor=1,
         exclude_test_resources=None,
@@ -40,7 +40,6 @@ def __init__(
         self.tags = tags or set()
         self.branches = branches
         self.not_branches = not_branches
-        self.parallel_builders = parallel_builders
         self.parallel_tests = parallel_tests
         self.timeout_factor = timeout_factor
         self.exclude_test_resources = exclude_test_resources or []
@@ -55,9 +54,13 @@ def __init__(
         if settings.use_local_worker:
             self.bb_worker = _worker.LocalWorker(name)
         else:
-            self.bb_worker = _worker.Worker(name, str(pw),
-                                            notify_on_missing=emails,
-                                            keepalive_interval=KEEPALIVE)
+            self.bb_worker = _worker.Worker(
+                name,
+                str(pw),
+                notify_on_missing=emails,
+                keepalive_interval=KEEPALIVE,
+                max_builds=parallel_builders,
+            )
 
 # Some of Itamar's workers are reprovisioned every Wednesday at 9am PT.
 # Builds scheduled between 8am - 10am PT on Wednesdays will be delayed to

master/master.cfg

@@ -133,14 +133,6 @@ c["workers"] = [w.bb_worker for w in WORKERS]
 c["builders"] = []
 c["schedulers"] = []
 
-# The following with the worker owners' agreement
-cpulock = locks.WorkerLock(
-    "cpu",
-    maxCountForWorker={
-        w.name: w.parallel_builders for w in WORKERS if w.parallel_builders
-    },
-)
-
 
 def is_important_file(filename):
     unimportant_prefixes = (
@@ -273,7 +265,6 @@ for branch in BRANCHES:
             builddir=f"{branch.builddir_name}.{worker.name}{f.buildersuffix}",
             factory=f,
             tags=tags,
-            locks=[cpulock.access("counting")],
         )
 
         if worker.downtime: