1 /* MC interface: definitions that non-MC modules must see, but not the user */
3 /* Copyright (c) 2014-2015. The SimGrid Team. All rights reserved. */
5 /* This program is free software; you can redistribute it and/or modify it
6 * under the terms of the license (GNU LGPL) which comes with this package. */
8 #include <unistd.h> // pread, pwrite
10 #include "mc_page_store.h"
12 #include "mc_private.h"
13 #include "mc_snapshot.h"
15 #include <xbt/mmalloc.h>
19 // ***** Region management:
21 /** @brief Take a per-page snapshot of a region
23 * @param data The start of the region (must be at the beginning of a page)
24 * @param pag_count Number of pages of the region
25 * @return Snapshot page numbers of this new snapshot
27 size_t* mc_take_page_snapshot_region(mc_process_t process,
28 void* data, size_t page_count)
30 size_t* pagenos = (size_t*) malloc(page_count * sizeof(size_t));
32 const bool is_self = MC_process_is_self(process);
36 temp = malloc(xbt_pagesize);
38 for (size_t i=0; i!=page_count; ++i) {
40 // Otherwise, we need to store the page the hard way
41 // (by reading its content):
42 void* page = (char*) data + (i << xbt_pagebits);
43 xbt_assert(mc_page_offset(page)==0, "Not at the beginning of a page");
48 /* Adding another copy (and a syscall) will probably slow things a lot.
49 TODO, optimize this somehow (at least by grouping the syscalls)
51 - reduce the number of syscalls;
52 - let the application snapshot itself;
53 - move the segments in shared memory (this will break `fork` however).
56 MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
57 temp, page, xbt_pagesize, MC_PROCESS_INDEX_DISABLED);
59 pagenos[i] = mc_model_checker->page_store().store_page(page_data);
67 void mc_free_page_snapshot_region(size_t* pagenos, size_t page_count)
69 for (size_t i=0; i!=page_count; ++i) {
70 mc_model_checker->page_store().unref_page(pagenos[i]);
74 /** @brief Restore a snapshot of a region
76 * If possible, the restoration will be incremental
77 * (the modified pages will not be touched).
80 * @param page_count Number of pages of the region
83 void mc_restore_page_snapshot_region(mc_process_t process,
84 void* start_addr, size_t page_count, size_t* pagenos)
86 for (size_t i=0; i!=page_count; ++i) {
87 // Otherwise, copy the page:
88 void* target_page = mc_page_from_number(start_addr, i);
89 const void* source_page = mc_model_checker->page_store().get_page(pagenos[i]);
90 MC_process_write(process, source_page, target_page, xbt_pagesize);
94 // ***** High level API
96 mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
97 void *start_addr, void* permanent_addr, size_t size)
99 mc_process_t process = &mc_model_checker->process();
101 mc_mem_region_t region = xbt_new(s_mc_mem_region_t, 1);
102 region->region_type = region_type;
103 region->storage_type = MC_REGION_STORAGE_TYPE_CHUNKED;
104 region->start_addr = start_addr;
105 region->permanent_addr = permanent_addr;
108 xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize-1)) == 0,
109 "Not at the beginning of a page");
110 xbt_assert((((uintptr_t)permanent_addr) & (xbt_pagesize-1)) == 0,
111 "Not at the beginning of a page");
112 size_t page_count = mc_page_count(size);
114 // Take incremental snapshot:
115 region->chunked.page_numbers = mc_take_page_snapshot_region(process,
116 permanent_addr, page_count);
121 void mc_region_restore_sparse(mc_process_t process, mc_mem_region_t reg)
123 xbt_assert((((uintptr_t)reg->permanent_addr) & (xbt_pagesize-1)) == 0,
124 "Not at the beginning of a page");
125 size_t page_count = mc_page_count(reg->size);
127 mc_restore_page_snapshot_region(process,
128 reg->permanent_addr, page_count, reg->chunked.page_numbers);