Mercurial > public > mercurial-scm > hg-stable

diff mercurial/exchange.py @ 26566:58880acd2369

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bundle2: allow lazily acquiring the lock In the external pushrebase extension, it is valuable to be able to do some work without taking the lock (like running expensive hooks). This enables significantly higher commit throughput. This patch adds an option to lazily acquire the lock. It means that all bundle2 part handlers that require writing to the repo must first call op.gettransction(), when in this mode.
author Durham Goode <durham@fb.com>
date Mon, 05 Oct 2015 16:19:54 -0700
parents 41dd7b2c7e15
children 56b2bcea2529
line wrap: on
line diff
--- a/mercurial/exchange.py	Tue Oct 06 14:42:29 2015 -0700
+++ b/mercurial/exchange.py	Mon Oct 05 16:19:54 2015 -0700
@@ -1441,7 +1441,8 @@
     If the push was raced as PushRaced exception is raised."""
     r = 0
     # need a transaction when processing a bundle2 stream
-    wlock = lock = tr = None
+    # [wlock, lock, tr] - needs to be an array so nested functions can modify it
+    lockandtr = [None, None, None]
     recordout = None
     # quick fix for output mismatch with bundle2 in 3.4
     captureoutput = repo.ui.configbool('experimental', 'bundle2-output-capture',
@@ -1454,13 +1455,22 @@
         if util.safehasattr(cg, 'params'):
             r = None
             try:
-                wlock = repo.wlock()
-                lock = repo.lock()
-                tr = repo.transaction(source)
-                tr.hookargs['source'] = source
-                tr.hookargs['url'] = url
-                tr.hookargs['bundle2'] = '1'
-                op = bundle2.bundleoperation(repo, lambda: tr,
+                def gettransaction():
+                    if not lockandtr[2]:
+                        lockandtr[0] = repo.wlock()
+                        lockandtr[1] = repo.lock()
+                        lockandtr[2] = repo.transaction(source)
+                        lockandtr[2].hookargs['source'] = source
+                        lockandtr[2].hookargs['url'] = url
+                        lockandtr[2].hookargs['bundle2'] = '1'
+                    return lockandtr[2]
+
+                # Do greedy locking by default until we're satisfied with lazy
+                # locking.
+                if not repo.ui.configbool('experimental', 'bundle2lazylocking'):
+                    gettransaction()
+
+                op = bundle2.bundleoperation(repo, gettransaction,
                                              captureoutput=captureoutput)
                 try:
                     op = bundle2.processbundle(repo, cg, op=op)
@@ -1470,7 +1480,8 @@
                         repo.ui.pushbuffer(error=True, subproc=True)
                         def recordout(output):
                             r.newpart('output', data=output, mandatory=False)
-                tr.close()
+                if lockandtr[2] is not None:
+                    lockandtr[2].close()
             except BaseException as exc:
                 exc.duringunbundle2 = True
                 if captureoutput and r is not None:
@@ -1481,10 +1492,10 @@
                         parts.append(part)
                 raise
         else:
-            lock = repo.lock()
+            lockandtr[1] = repo.lock()
             r = changegroup.addchangegroup(repo, cg, source, url)
     finally:
-        lockmod.release(tr, lock, wlock)
+        lockmod.release(lockandtr[2], lockandtr[1], lockandtr[0])
         if recordout is not None:
             recordout(repo.ui.popbuffer())
     return r