X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/64a1599658f6c313f789471fc829a574fa32bd70..9b00b25919fb4fe7311031c78a13e7ae2055df70:/src/mc/RegionSnapshot.cpp

diff --git a/src/mc/RegionSnapshot.cpp b/src/mc/RegionSnapshot.cpp
index 634aadc85b..bfcc7ba35a 100644
--- a/src/mc/RegionSnapshot.cpp
+++ b/src/mc/RegionSnapshot.cpp
@@ -4,11 +4,15 @@
 /* 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. */
 
+#include <cstdlib>
+
 #include <sys/mman.h>
 
 #include "mc/mc.h"
-#include "mc_snapshot.h"
-#include "RegionSnapshot.hpp"
+#include "src/mc/mc_snapshot.h"
+
+#include "src/mc/ChunkedData.hpp"
+#include "src/mc/RegionSnapshot.hpp"
 
 extern "C" {
 
@@ -35,33 +39,72 @@ const char* to_cstr(RegionType region)
   }
 }
 
-void data_deleter::operator()(void* p) const
+Buffer::Buffer(std::size_t size, Type type) : size_(size), type_(type)
 {
   switch(type_) {
-  case Free:
-    free(p);
+  case Type::Malloc:
+    data_ = ::malloc(size_);
     break;
-  case Munmap:
-    munmap(p, size_);
+  case Type::Mmap:
+    data_ = ::mmap(nullptr, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE, -1, 0);
+    if (data_ == MAP_FAILED) {
+      data_ = nullptr;
+      size_ = 0;
+      type_ = Type::Malloc;
+      throw std::bad_alloc();
+    }
     break;
+  default:
+    abort();
   }
 }
 
+void Buffer::clear() noexcept
+{
+  switch(type_) {
+  case Type::Malloc:
+    std::free(data_);
+    break;
+  case Type::Mmap:
+    if (munmap(data_, size_) != 0)
+      abort();
+    break;
+  default:
+    abort();
+  }
+  data_ = nullptr;
+  size_ = 0;
+  type_ = Type::Malloc;
+}
+
 RegionSnapshot dense_region(
   RegionType region_type,
   void *start_addr, void* permanent_addr, size_t size)
 {
-  simgrid::mc::RegionSnapshot::flat_data_ptr data((char*) malloc(size));
+  // When KSM support is enables, we allocate memory using mmap:
+  // * we don't want to madvise bits of the heap;
+  // * mmap gives data aligned on page boundaries which is merge friendly.
+  simgrid::mc::Buffer data;
+  if (_sg_mc_ksm)
+    data = Buffer::mmap(size);
+  else
+    data = Buffer::malloc(size);
+
   mc_model_checker->process().read_bytes(data.get(), size,
     remote(permanent_addr),
     simgrid::mc::ProcessIndexDisabled);
 
+  if (_sg_mc_ksm)
+    // Mark the region as mergeable *after* we have written into it.
+    // Trying to merge them before is useless/counterproductive.
+    madvise(data.get(), size, MADV_MERGEABLE);
+
   simgrid::mc::RegionSnapshot region(
     region_type, start_addr, permanent_addr, size);
   region.flat_data(std::move(data));
 
   XBT_DEBUG("New region : type : %s, data : %p (real addr %p), size : %zu",
-            to_cstr(region_type), region.flat_data(), permanent_addr, size);
+            to_cstr(region_type), region.flat_data().get(), permanent_addr, size);
   return std::move(region);
 }
 
@@ -73,19 +116,26 @@ RegionSnapshot dense_region(
  * @param size         Size of the data*
  */
 RegionSnapshot region(
-  RegionType type, void *start_addr, void* permanent_addr, size_t size)
+  RegionType type, void *start_addr, void* permanent_addr, size_t size,
+  RegionSnapshot const* ref_region)
 {
   if (_sg_mc_sparse_checkpoint) {
-    return sparse_region(type, start_addr, permanent_addr, size);
+    return sparse_region(type, start_addr, permanent_addr, size, ref_region);
   } else  {
     return dense_region(type, start_addr, permanent_addr, size);
   }
 }
 
 RegionSnapshot sparse_region(RegionType region_type,
-  void *start_addr, void* permanent_addr, size_t size)
+  void *start_addr, void* permanent_addr, size_t size,
+  RegionSnapshot const* ref_region)
 {
   simgrid::mc::Process* process = &mc_model_checker->process();
+  assert(process != nullptr);
+
+  bool use_soft_dirty = _sg_mc_sparse_checkpoint && _sg_mc_soft_dirty
+    && ref_region != nullptr
+    && ref_region->storage_type() == simgrid::mc::StorageType::Chunked;
 
   xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize-1)) == 0,
     "Not at the beginning of a page");
@@ -93,8 +143,19 @@ RegionSnapshot sparse_region(RegionType region_type,
     "Not at the beginning of a page");
   size_t page_count = mc_page_count(size);
 
-  simgrid::mc::PerPageCopy page_data(mc_model_checker->page_store(), *process,
-      permanent_addr, page_count);
+  std::vector<std::uint64_t> pagemap;
+  const size_t* ref_page_numbers = nullptr;
+  if (use_soft_dirty) {
+    pagemap.resize(page_count);
+    process->read_pagemap(pagemap.data(),
+      mc_page_number(nullptr, permanent_addr), page_count);
+    ref_page_numbers = ref_region->page_data().pagenos();
+  }
+
+  simgrid::mc::ChunkedData page_data(
+    mc_model_checker->page_store(), *process, permanent_addr, page_count,
+    ref_page_numbers,
+    use_soft_dirty ? pagemap.data() : nullptr);
 
   simgrid::mc::RegionSnapshot region(
     region_type, start_addr, permanent_addr, size);