[pypy-commit] stmgc c8-new-page-handling: a few fixes for freeing backup copies, not releasing a lock, and inevitable transaction validation

[Raemi]

Author: Remi Meier <remi.meier at inf.ethz.ch>
Branch: c8-new-page-handling
Changeset: r1429:504914e27b52
Date: 2014-09-26 14:30 +0200
http://bitbucket.org/pypy/stmgc/changeset/504914e27b52/

Log:	a few fixes for freeing backup copies, not releasing a lock, and
	inevitable transaction validation

diff --git a/c8/stm/core.c b/c8/stm/core.c
--- a/c8/stm/core.c
+++ b/c8/stm/core.c
@@ -228,12 +228,18 @@
        the committed objs. */
     struct stm_commit_log_entry_s *cl = STM_PSEGMENT->last_commit_log_entry;
     struct stm_commit_log_entry_s *next_cl;
+    int my_segnum = STM_SEGMENT->segment_num;
     /* Don't check this 'cl'. This entry is already checked */
 
+    if (STM_PSEGMENT->transaction_state == TS_INEVITABLE) {
+        assert(cl->next == -1);
+        return;
+    }
+
     /* We need this lock to prevent a segfault handler in a different thread
        from seeing inconsistent data.  It could also be done by carefully
        ordering things, but later. */
-    acquire_modified_objs_lock(STM_SEGMENT->segment_num);
+    acquire_modified_objs_lock(my_segnum);
 
     /* XXXXXXXXXX: we shouldn't be able to update pages while someone else copies
        from our pages (signal handler / import objs) */
@@ -243,6 +249,7 @@
     while ((next_cl = cl->next) != NULL) {
         if (next_cl == (void *)-1) {
             /* there is an inevitable transaction running */
+            release_modified_objs_lock(my_segnum);
 #if STM_TESTS
             if (free_if_abort != (void *)-1)
                 free(free_if_abort);
@@ -254,6 +261,7 @@
                          if it wants to */
 
             _stm_collectable_safe_point();
+            acquire_modified_objs_lock(my_segnum);
             continue;
         }
         assert(next_cl->rev_num > cl->rev_num);
@@ -272,9 +280,9 @@
                        then we will proceed below to update our segment from
                        the old (but unmodified) version to the newer version.
                     */
-                    release_modified_objs_lock(STM_SEGMENT->segment_num);
-                    reset_modified_from_backup_copies(STM_SEGMENT->segment_num);
-                    acquire_modified_objs_lock(STM_SEGMENT->segment_num);
+                    release_modified_objs_lock(my_segnum);
+                    reset_modified_from_backup_copies(my_segnum);
+                    acquire_modified_objs_lock(my_segnum);
                     needs_abort = true;
                     break;
                 }
@@ -292,7 +300,7 @@
         STM_PSEGMENT->last_commit_log_entry = cl;
     }
 
-    release_modified_objs_lock(STM_SEGMENT->segment_num);
+    release_modified_objs_lock(my_segnum);
 
     /* XXXXXXXXXXXXXXXX CORRECT LOCKING NEEDED XXXXXXXXXXXXXXXXXXXXXX */
     int segnum;
@@ -682,7 +690,11 @@
         memcpy(dst + SLICE_OFFSET(undo->slice),
                undo->backup,
                SLICE_SIZE(undo->slice));
-        free(undo->backup);
+
+        if (SLICE_OFFSET(undo->slice) == 0) {
+            /* only free bk copy once: */
+            free(undo->backup);
+        }
     }
 
     /* check that all objects have the GCFLAG_WRITE_BARRIER afterwards */
diff --git a/c8/test/test_random.py b/c8/test/test_random.py
--- a/c8/test/test_random.py
+++ b/c8/test/test_random.py
@@ -10,7 +10,7 @@
         self.thread_num = 0
 
     def do(self, cmd):
-        color = "\033[%dm" % (31 + self.thread_num % 6)
+        color = ">> \033[%dm" % (31 + (self.thread_num + 5) % 6)
         print >> sys.stderr, color + cmd + "\033[0m"
         exec cmd in globals(), self.content