[mc] Bring back soft-dirty tracking from the dead 💀

[simgrid.git] / src / mc / mc_page_snapshot.cpp

diff --git a/src/mc/mc_page_snapshot.cpp b/src/mc/mc_page_snapshot.cpp
index f0fb2c1..b180c40 100644 (file)
--- a/src/mc/mc_page_snapshot.cpp
+++ b/src/mc/mc_page_snapshot.cpp
@@ -1,6 +1,7 @@
 /* MC interface: definitions that non-MC modules must see, but not the user */
 
-/* Copyright (c) 2014-2015. The SimGrid Team.  All rights reserved.         */
+/* Copyright (c) 2014-2015. The SimGrid Team.
+ * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
@@ -14,6 +15,9 @@
 
 #include <xbt/mmalloc.h>
 
+#define SOFT_DIRTY_BIT_NUMBER 55
+#define SOFT_DIRTY (((uint64_t)1) << SOFT_DIRTY_BIT_NUMBER)
+
 using simgrid::mc::remote;
 
 namespace simgrid {
@@ -26,7 +30,8 @@ namespace mc {
  *  @return                Snapshot page numbers of this new snapshot
  */
 PerPageCopy::PerPageCopy(PageStore& store, AddressSpace& as,
-    remote_ptr<void> addr, std::size_t page_count)
+    remote_ptr<void> addr, std::size_t page_count,
+    const size_t* ref_page_numbers, const std::uint64_t* pagemap)
 {
   store_ = &store;
   this->pagenos_.resize(page_count);
@@ -34,6 +39,13 @@ PerPageCopy::PerPageCopy(PageStore& store, AddressSpace& as,
 
   for (size_t i = 0; i != page_count; ++i) {
 
+    // We don't have to compare soft-clean pages:
+    if (ref_page_numbers && pagemap && !(pagemap[i] & SOFT_DIRTY)) {
+      pagenos_[i] = ref_page_numbers[i];
+      store_->ref_page(ref_page_numbers[i]);
+      continue;
+    }
+
       remote_ptr<void> page = remote(addr.address() + (i << xbt_pagebits));
       xbt_assert(mc_page_offset((void*)page.address())==0,
         "Not at the beginning of a page");
@@ -69,7 +81,7 @@ extern "C" {
  *  @param page_count       Number of pages of the region
  *  @param pagenos
  */
-void mc_restore_page_snapshot_region(mc_process_t process,
+void mc_restore_page_snapshot_region(simgrid::mc::Process* process,
   void* start_addr, simgrid::mc::PerPageCopy const& pages_copy)
 {
   for (size_t i = 0; i != pages_copy.page_count(); ++i) {
@@ -82,29 +94,7 @@ void mc_restore_page_snapshot_region(mc_process_t process,
 
 // ***** High level API
 
-mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
-  void *start_addr, void* permanent_addr, size_t size)
-{
-  mc_process_t process = &mc_model_checker->process();
-
-  xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize-1)) == 0,
-    "Not at the beginning of a page");
-  xbt_assert((((uintptr_t)permanent_addr) & (xbt_pagesize-1)) == 0,
-    "Not at the beginning of a page");
-  size_t page_count = mc_page_count(size);
-
-  simgrid::mc::PerPageCopy page_data =
-    simgrid::mc::PerPageCopy(mc_model_checker->page_store(), *process,
-      permanent_addr, page_count);
-
-  mc_mem_region_t region = new simgrid::mc::RegionSnapshot(
-    region_type, start_addr, permanent_addr, size);
-  region->page_data(std::move(page_data));
-
-  return region;
-}
-
-void mc_region_restore_sparse(mc_process_t process, mc_mem_region_t reg)
+void mc_region_restore_sparse(simgrid::mc::Process* process, mc_mem_region_t reg)
 {
   xbt_assert(((reg->permanent_address().address()) & (xbt_pagesize-1)) == 0,
     "Not at the beginning of a page");