[pypy-commit] stmgc c7-refactor: Re-share the nursery pages after a minor collection

[arigo]

Author: Armin Rigo <ar...@tunes.org>
Branch: c7-refactor
Changeset: r811:a8f773df8a63
Date: 2014-02-22 18:27 +0100
http://bitbucket.org/pypy/stmgc/changeset/a8f773df8a63/

Log:    Re-share the nursery pages after a minor collection

diff --git a/c7/stm/nursery.c b/c7/stm/nursery.c
--- a/c7/stm/nursery.c
+++ b/c7/stm/nursery.c
@@ -383,6 +383,8 @@
     collect_oldrefs_to_nursery(old_objects_pointing_to_young);
 
     reset_nursery();
+
+    pages_make_shared_again(FIRST_NURSERY_PAGE, NB_NURSERY_PAGES);
 }
 
 
diff --git a/c7/stm/pages.c b/c7/stm/pages.c
--- a/c7/stm/pages.c
+++ b/c7/stm/pages.c
@@ -5,9 +5,9 @@
 
 static void pages_initialize_shared(uintptr_t pagenum, uintptr_t count)
 {
-    /* call remap_file_pages() to make all pages in the
-       range(pagenum, pagenum+count) refer to the same
-       physical range of pages from segment 0 */
+    /* call remap_file_pages() to make all pages in the range(pagenum,
+       pagenum+count) refer to the same physical range of pages from
+       segment 0. */
     uintptr_t i;
     for (i = 1; i < NB_SEGMENTS; i++) {
         char *segment_base = get_segment_base(i);
@@ -19,9 +19,27 @@
             abort();
         }
     }
-    for (i = 0; i < count; i++) {
-        assert(flag_page_private[pagenum + i] == FREE_PAGE);
+    for (i = 0; i < count; i++)
         flag_page_private[pagenum + i] = SHARED_PAGE;
+}
+
+static void pages_make_shared_again(uintptr_t pagenum, uintptr_t count)
+{
+    /* Same as pages_initialize_shared(), but tries hard to minimize the
+       total number of pages that remap_file_pages() must handle, by
+       fragmenting calls as much as possible (the overhead of one system
+       call appears smaller as the overhead per page). */
+    uintptr_t start, i = 0;
+    while (i < count) {
+        if (flag_page_private[pagenum + (i++)] == SHARED_PAGE)
+            continue;
+        start = i;    /* first index of a private page */
+        while (1) {
+            i++;
+            if (i == count || flag_page_private[pagenum + i] == SHARED_PAGE)
+                break;
+        }
+        pages_initialize_shared(pagenum + start, i - start);
     }
 }
 
diff --git a/c7/stm/pages.h b/c7/stm/pages.h
--- a/c7/stm/pages.h
+++ b/c7/stm/pages.h
@@ -20,6 +20,7 @@
 
 static void _pages_privatize(uintptr_t pagenum, uintptr_t count, bool full);
 static void pages_initialize_shared(uintptr_t pagenum, uintptr_t count);
+static void pages_make_shared_again(uintptr_t pagenum, uintptr_t count);
 
 inline static void pages_privatize(uintptr_t pagenum, uintptr_t count,
                                    bool full) {
_______________________________________________
pypy-commit mailing list
pypy-commit@python.org
https://mail.python.org/mailman/listinfo/pypy-commit