--- /dev/null
+/* Copyright (c) 2007-2018. 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. */
+
+#include <cstdlib>
+
+#include <sys/mman.h>
+#ifdef __FreeBSD__
+#define MAP_POPULATE MAP_PREFAULT_READ
+#endif
+
+#include "mc/mc.h"
+#include "src/mc/mc_config.hpp"
+#include "src/mc/sosp/mc_snapshot.hpp"
+
+#include "src/mc/sosp/ChunkedData.hpp"
+#include "src/mc/sosp/RegionSnapshot.hpp"
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_RegionSnaphot, mc, "Logging specific to region snapshots");
+
+namespace simgrid {
+namespace mc {
+
+static inline const char* to_cstr(RegionType region)
+{
+ switch (region) {
+ case RegionType::Unknown:
+ return "unknown";
+ case RegionType::Heap:
+ return "Heap";
+ case RegionType::Data:
+ return "Data";
+ default:
+ return "?";
+ }
+}
+
+Buffer::Buffer(std::size_t size, Type type) : size_(size), type_(type)
+{
+ switch (type_) {
+ case Type::Malloc:
+ data_ = ::operator new(size_);
+ break;
+ 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:
+ ::operator delete(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)
+{
+ // When KSM support is enables, we allocate memory using mmap:
+ // * we don't want to advise bits of the heap as mergable
+ // * 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);
+
+#ifdef __linux__
+ 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);
+#endif
+
+ 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().get(), permanent_addr, size);
+ return region;
+}
+
+/** @brief Take a snapshot of a given region
+ *
+ * @param type
+ * @param start_addr Address of the region in the simulated process
+ * @param permanent_addr Permanent address of this data (for privatized variables, this is the virtual address of the
+ * privatized mapping)
+ * @param size Size of the data*
+ */
+RegionSnapshot region(RegionType type, void* start_addr, void* permanent_addr, size_t size)
+{
+ if (_sg_mc_sparse_checkpoint)
+ return sparse_region(type, start_addr, permanent_addr, size);
+ 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)
+{
+ simgrid::mc::RemoteClient* process = &mc_model_checker->process();
+ assert(process != nullptr);
+
+ 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 = simgrid::mc::mmu::chunkCount(size);
+
+ simgrid::mc::ChunkedData page_data(mc_model_checker->page_store(), *process, RemotePtr<void>(permanent_addr),
+ page_count);
+
+ simgrid::mc::RegionSnapshot region(region_type, start_addr, permanent_addr, size);
+ region.page_data(std::move(page_data));
+ return region;
+}
+
+} // namespace mc
+} // namespace simgrid
