1 /* Copyright (c) 2007-2015. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
12 #include "src/mc/mc_snapshot.h"
14 #include "src/mc/ChunkedData.hpp"
15 #include "src/mc/RegionSnapshot.hpp"
19 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_RegionSnaphot, mc,
20 "Logging specific to region snapshots");
28 const char* to_cstr(RegionType region)
31 case RegionType::Unknown:
33 case RegionType::Heap:
35 case RegionType::Data:
42 buffer::buffer(std::size_t size, Type type) : size_(size), type_(type)
46 data_ = malloc(size_);
49 data_ = mmap(nullptr, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE, -1, 0);
50 if (data_ == MAP_FAILED) {
54 throw std::bad_alloc();
62 void buffer::clear() noexcept
69 if (munmap(data_, size_) != 0)
80 RegionSnapshot dense_region(
81 RegionType region_type,
82 void *start_addr, void* permanent_addr, size_t size)
84 simgrid::mc::buffer::Type buffer_type;
86 // We use mmap to allocate the memory in order to madvise it.
87 // We don't want to madvise the main heap.
88 // Moreover we get aligned pgaes which is merge-friendly.
89 buffer_type = simgrid::mc::buffer::Type::Mmap;
91 buffer_type = simgrid::mc::buffer::Type::Malloc;
93 simgrid::mc::buffer data(size, buffer_type);
95 mc_model_checker->process().read_bytes(data.get(), size,
96 remote(permanent_addr),
97 simgrid::mc::ProcessIndexDisabled);
100 // Mark the region as mergeable *after* we have written into it.
101 // There no point to let KSM do the hard work before that.
102 madvise(data.get(), size, MADV_MERGEABLE);
104 simgrid::mc::RegionSnapshot region(
105 region_type, start_addr, permanent_addr, size);
106 region.flat_data(std::move(data));
108 XBT_DEBUG("New region : type : %s, data : %p (real addr %p), size : %zu",
109 to_cstr(region_type), region.flat_data().get(), permanent_addr, size);
110 return std::move(region);
113 /** @brief Take a snapshot of a given region
116 * @param start_addr Address of the region in the simulated process
117 * @param permanent_addr Permanent address of this data (for privatized variables, this is the virtual address of the privatized mapping)
118 * @param size Size of the data*
120 RegionSnapshot region(
121 RegionType type, void *start_addr, void* permanent_addr, size_t size,
122 RegionSnapshot const* ref_region)
124 if (_sg_mc_sparse_checkpoint) {
125 return sparse_region(type, start_addr, permanent_addr, size, ref_region);
127 return dense_region(type, start_addr, permanent_addr, size);
131 RegionSnapshot sparse_region(RegionType region_type,
132 void *start_addr, void* permanent_addr, size_t size,
133 RegionSnapshot const* ref_region)
135 simgrid::mc::Process* process = &mc_model_checker->process();
136 assert(process != nullptr);
138 bool use_soft_dirty = _sg_mc_sparse_checkpoint && _sg_mc_soft_dirty
139 && ref_region != nullptr
140 && ref_region->storage_type() == simgrid::mc::StorageType::Chunked;
142 xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize-1)) == 0,
143 "Not at the beginning of a page");
144 xbt_assert((((uintptr_t)permanent_addr) & (xbt_pagesize-1)) == 0,
145 "Not at the beginning of a page");
146 size_t page_count = mc_page_count(size);
148 std::vector<std::uint64_t> pagemap;
149 const size_t* ref_page_numbers = nullptr;
150 if (use_soft_dirty) {
151 pagemap.resize(page_count);
152 process->read_pagemap(pagemap.data(),
153 mc_page_number(nullptr, permanent_addr), page_count);
154 ref_page_numbers = ref_region->page_data().pagenos();
157 simgrid::mc::ChunkedData page_data(
158 mc_model_checker->page_store(), *process, permanent_addr, page_count,
160 use_soft_dirty ? pagemap.data() : nullptr);
162 simgrid::mc::RegionSnapshot region(
163 region_type, start_addr, permanent_addr, size);
164 region.page_data(std::move(page_data));
165 return std::move(region);