[pypy-commit] pypy stmgc-c8-gcc: import stmgc with hashtable fixes

[Raemi]

Author: Remi Meier <remi.meier at inf.ethz.ch>
Branch: stmgc-c8-gcc
Changeset: r79533:64cda3ebddce
Date: 2015-09-08 13:20 +0200
http://bitbucket.org/pypy/pypy/changeset/64cda3ebddce/

Log:	import stmgc with hashtable fixes

diff --git a/rpython/translator/stm/src_stm/revision b/rpython/translator/stm/src_stm/revision
--- a/rpython/translator/stm/src_stm/revision
+++ b/rpython/translator/stm/src_stm/revision
@@ -1,1 +1,1 @@
-bba995bf44bc
+8cba33de2246+
diff --git a/rpython/translator/stm/src_stm/stm/core.c b/rpython/translator/stm/src_stm/stm/core.c
--- a/rpython/translator/stm/src_stm/stm/core.c
+++ b/rpython/translator/stm/src_stm/stm/core.c
@@ -1212,6 +1212,8 @@
                                  in abort_data_structures_from_segment_num() */
         STM_SEGMENT->nursery_mark = ((stm_char *)_stm_nursery_start +
                                      stm_fill_mark_nursery_bytes);
+    } else if (repeat_count >= 5) {
+        _stm_become_inevitable("too many retries");
     }
     return repeat_count;
 }
diff --git a/rpython/translator/stm/src_stm/stm/hashtable.c b/rpython/translator/stm/src_stm/stm/hashtable.c
--- a/rpython/translator/stm/src_stm/stm/hashtable.c
+++ b/rpython/translator/stm/src_stm/stm/hashtable.c
@@ -150,8 +150,9 @@
 
 static void _stm_rehash_hashtable(stm_hashtable_t *hashtable,
                                   uintptr_t biggercount,
-                                  char *segment_base)
+                                  long segnum) /* segnum=-1 if no major GC */
 {
+    char *segment_base = segnum == -1 ? NULL : get_segment_base(segnum);
     dprintf(("rehash %p to size %ld, segment_base=%p\n",
              hashtable, biggercount, segment_base));
 
@@ -175,22 +176,26 @@
         stm_hashtable_entry_t *entry = table->items[j];
         if (entry == NULL)
             continue;
-        if (segment_base != NULL) {
+
+        char *to_read_from = segment_base;
+        if (segnum != -1) {
             /* -> compaction during major GC */
+            to_read_from = get_page_status_in(segnum, (uintptr_t)entry / 4096UL) == PAGE_NO_ACCESS
+                ? stm_object_pages : to_read_from;
             if (((struct stm_hashtable_entry_s *)
-                       REAL_ADDRESS(segment_base, entry))->object == NULL &&
-                   !_stm_was_read_by_anybody((object_t *)entry)) {
-                dprintf(("  removing dead %p\n", entry));
+                 REAL_ADDRESS(to_read_from, entry))->object == NULL &&
+                !_stm_was_read_by_anybody((object_t *)entry)) {
+                dprintf(("  removing dead %p at %ld\n", entry, j));
                 continue;
             }
         }
 
         uintptr_t eindex;
-        if (segment_base == NULL)
+        if (segnum == -1)
             eindex = entry->index;   /* read from STM_SEGMENT */
         else
             eindex = ((struct stm_hashtable_entry_s *)
-                       REAL_ADDRESS(segment_base, entry))->index;
+                       REAL_ADDRESS(to_read_from, entry))->index;
 
         dprintf(("  insert_clean %p at index=%ld\n",
                  entry, eindex));
@@ -222,8 +227,10 @@
     i = index & mask;
     entry = VOLATILE_TABLE(table)->items[i];
     if (entry != NULL) {
-        if (entry->index == index)
+        if (entry->index == index) {
+            stm_read((object_t*)entry);
             return entry;           /* found at the first try */
+        }
 
         uintptr_t perturb = index;
         while (1) {
@@ -231,8 +238,10 @@
             i &= mask;
             entry = VOLATILE_TABLE(table)->items[i];
             if (entry != NULL) {
-                if (entry->index == index)
+                if (entry->index == index) {
+                    stm_read((object_t*)entry);
                     return entry;    /* found */
+                }
             }
             else
                 break;
@@ -326,16 +335,11 @@
                 stm_allocate_preexisting(sizeof(stm_hashtable_entry_t),
                                          (char *)&initial.header);
             hashtable->additions++;
-            /* make sure .object is NULL in all segments before
-               "publishing" the entry in the hashtable.  In other words,
-               the following write_fence() prevents a partially
-               initialized 'entry' from showing up in table->items[i],
-               where it could be read from other threads. */
-            write_fence();
         }
         table->items[i] = entry;
         write_fence();     /* make sure 'table->items' is written here */
         VOLATILE_TABLE(table)->resize_counter = rc - 6;    /* unlock */
+        stm_read((object_t*)entry);
         return entry;
     }
     else {
@@ -346,7 +350,7 @@
             biggercount *= 4;
         else
             biggercount *= 2;
-        _stm_rehash_hashtable(hashtable, biggercount, /*segment_base=*/NULL);
+        _stm_rehash_hashtable(hashtable, biggercount, /*segnum=*/-1);
         goto restart;
     }
 }
@@ -507,7 +511,7 @@
         assert(count <= table->mask + 1);
 
         dprintf(("compact with %ld items:\n", num_entries_times_6 / 6));
-        _stm_rehash_hashtable(hashtable, count, get_segment_base(segnum));
+        _stm_rehash_hashtable(hashtable, count, segnum);
     }
 
     table = hashtable->table;
diff --git a/rpython/translator/stm/src_stm/stmgc.h b/rpython/translator/stm/src_stm/stmgc.h
--- a/rpython/translator/stm/src_stm/stmgc.h
+++ b/rpython/translator/stm/src_stm/stmgc.h
@@ -725,6 +725,9 @@
 
 stm_hashtable_t *stm_hashtable_create(void);
 void stm_hashtable_free(stm_hashtable_t *);
+/* lookup returns a reference to an entry. This entry is only valid
+   in the current transaction and needs to be looked up again if there
+   may have been a break inbetween. */
 stm_hashtable_entry_t *stm_hashtable_lookup(object_t *, stm_hashtable_t *,
                                             uintptr_t key);
 object_t *stm_hashtable_read(object_t *, stm_hashtable_t *, uintptr_t key);