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. */
11 # define MAP_POPULATE MAP_PREFAULT_READ
15 #include "src/mc/mc_snapshot.h"
17 #include "src/mc/ChunkedData.hpp"
18 #include "src/mc/RegionSnapshot.hpp"
20 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_RegionSnaphot, mc,
21 "Logging specific to region snapshots");
27 const char* to_cstr(RegionType region)
30 case RegionType::Unknown:
32 case RegionType::Heap:
34 case RegionType::Data:
41 Buffer::Buffer(std::size_t size, Type type) : size_(size), type_(type)
45 data_ = ::malloc(size_);
48 data_ = ::mmap(nullptr, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE, -1, 0);
49 if (data_ == MAP_FAILED) {
53 throw std::bad_alloc();
61 void Buffer::clear() noexcept
68 if (munmap(data_, size_) != 0)
79 RegionSnapshot dense_region(
80 RegionType region_type,
81 void *start_addr, void* permanent_addr, size_t size)
83 // When KSM support is enables, we allocate memory using mmap:
84 // * we don't want to advise bits of the heap as mergable;
85 // * mmap gives data aligned on page boundaries which is merge friendly.
86 simgrid::mc::Buffer data;
88 data = Buffer::mmap(size);
90 data = Buffer::malloc(size);
92 mc_model_checker->process().read_bytes(data.get(), size,
93 remote(permanent_addr),
94 simgrid::mc::ProcessIndexDisabled);
97 // Mark the region as mergeable *after* we have written into it.
98 // Trying to merge them before is useless/counterproductive.
99 madvise(data.get(), size, MADV_MERGEABLE);
101 simgrid::mc::RegionSnapshot region(
102 region_type, start_addr, permanent_addr, size);
103 region.flat_data(std::move(data));
105 XBT_DEBUG("New region : type : %s, data : %p (real addr %p), size : %zu",
106 to_cstr(region_type), region.flat_data().get(), permanent_addr, size);
110 /** @brief Take a snapshot of a given region
113 * @param start_addr Address of the region in the simulated process
114 * @param permanent_addr Permanent address of this data (for privatized variables, this is the virtual address of the privatized mapping)
115 * @param size Size of the data*
117 RegionSnapshot region(
118 RegionType type, void *start_addr, void* permanent_addr, size_t size)
120 if (_sg_mc_sparse_checkpoint)
121 return sparse_region(type, start_addr, permanent_addr, size);
123 return dense_region(type, start_addr, permanent_addr, size);
126 RegionSnapshot sparse_region(RegionType region_type,
127 void *start_addr, void* permanent_addr, size_t size)
129 simgrid::mc::Process* process = &mc_model_checker->process();
130 assert(process != nullptr);
132 xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize-1)) == 0,
133 "Not at the beginning of a page");
134 xbt_assert((((uintptr_t)permanent_addr) & (xbt_pagesize-1)) == 0,
135 "Not at the beginning of a page");
136 size_t page_count = simgrid::mc::mmu::chunkCount(size);
138 simgrid::mc::ChunkedData page_data(
139 mc_model_checker->page_store(), *process, permanent_addr, page_count);
141 simgrid::mc::RegionSnapshot region(
142 region_type, start_addr, permanent_addr, size);
143 region.page_data(std::move(page_data));