[pypy-commit] pypy stm-thread: Tweak.

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: stm-thread
Changeset: r55530:79d99ff94bf2
Date: 2012-06-08 21:16 +0200
http://bitbucket.org/pypy/pypy/changeset/79d99ff94bf2/

Log:	Tweak.

diff --git a/pypy/translator/stm/src_stm/core.c b/pypy/translator/stm/src_stm/core.c
--- a/pypy/translator/stm/src_stm/core.c
+++ b/pypy/translator/stm/src_stm/core.c
@@ -89,7 +89,8 @@
   return d->active == 2;
 }
 
-/*** run the redo log to commit a transaction, and release the locks */
+/*** run the redo log to commit a transaction, and release the locks.
+     Cannot abort any more. */
 static void tx_redo(struct tx_descriptor *d, owner_version_t newver)
 {
   wlog_t *item;
@@ -343,7 +344,7 @@
   acquireLocks(d);
 }
 
-static void commitInevitableTransaction(struct tx_descriptor *d)
+static owner_version_t commitInevitableTransaction(struct tx_descriptor *d)
 {
   unsigned long ts;
   _Bool ok;
@@ -356,10 +357,12 @@
   set_global_timestamp(d, ts);
   assert(ts == (d->start_time + 2));
 
-  // run the redo log, and release the locks
-  tx_redo(d, ts);
+  /* we still have the locks acquired, but we changed the global timestamp
+   * and we can release the mutex here.  The locked orecs will be updated
+   * immediately afterwards by tx_redo(). */
+  mutex_unlock();
 
-  mutex_unlock();
+  return ts;
 }
 
 /* lazy/lazy read instrumentation */
@@ -571,6 +574,7 @@
 
 void stm_commit_transaction(void)
 {
+  owner_version_t end_time;
   struct tx_descriptor *d = thread_descriptor;
   assert(d->active != 0);
 
@@ -597,11 +601,10 @@
 
   if (is_inevitable(d))
     {
-      commitInevitableTransaction(d);
+      end_time = commitInevitableTransaction(d);
     }
   else
     {
-      owner_version_t end_time;
       while (1)
         {
           unsigned long expected = get_global_timestamp(d);
@@ -622,10 +625,10 @@
       // validate (but skip validation if nobody else committed)
       if (end_time != (d->start_time + 2))
         validate(d);
+    }
 
-      // run the redo log, and release the locks
-      tx_redo(d, end_time);
-    }
+  // run the redo log, and release the locks
+  tx_redo(d, end_time);
 
   // remember that this was a commit
   d->num_commits++;