+#include <unistd.h> // pread, pwrite
+
#include "mc_page_store.h"
#include "mc_mmu.h"
+#include "mc_private.h"
+#include "mc_snapshot.h"
#include <xbt/mmalloc.h>
// ***** Region management:
-size_t* mc_take_page_snapshot_region(void* data, size_t page_count, uint64_t* pagemap, size_t* reference_pages)
+/** @brief Take a per-page snapshot of a region
+ *
+ * @param data The start of the region (must be at the beginning of a page)
+ * @param pag_count Number of pages of the region
+ * @param pagemap Linux kernel pagemap values fot this region (or NULL)
+ * @param reference_pages Snapshot page numbers of the previous soft_dirty_reset (or NULL)
+ * @return Snapshot page numbers of this new snapshot
+ */
+size_t* mc_take_page_snapshot_region(mc_process_t process,
+ void* data, size_t page_count, uint64_t* pagemap, size_t* reference_pages)
{
size_t* pagenos = (size_t*) malloc(page_count * sizeof(size_t));
+ const bool is_self = MC_process_is_self(process);
+
+ void* temp = NULL;
+ if (!is_self)
+ temp = malloc(xbt_pagebits);
+
for (size_t i=0; i!=page_count; ++i) {
bool softclean = pagemap && !(pagemap[i] & SOFT_DIRTY);
- if (softclean) {
+ if (softclean && reference_pages) {
// The page is softclean, it is the same page as the reference page:
pagenos[i] = reference_pages[i];
mc_model_checker->pages->ref_page(reference_pages[i]);
} else {
- // Otherwise, we need to store the page the hard hard
+ // Otherwise, we need to store the page the hard way
// (by reading its content):
void* page = (char*) data + (i << xbt_pagebits);
- pagenos[i] = mc_model_checker->pages->store_page(page);
+ xbt_assert(mc_page_offset(page)==0, "Not at the beginning of a page");
+ void* page_data;
+ if (is_self) {
+ page_data = page;
+ } else {
+ /* Adding another copy (and a syscall) will probably slow things a lot.
+ TODO, optimize this somehow (at least by grouping the syscalls)
+ if needed. Either:
+ - reduce the number of syscalls;
+ - let the application snapshot itself;
+ - move the segments in shared memory (this will break `fork` however).
+ */
+ page_data = temp;
+ MC_process_read(process, temp, page, xbt_pagesize);
+ }
+ pagenos[i] = mc_model_checker->pages->store_page(page_data);
}
}
+ free(temp);
return pagenos;
}
}
}
-void mc_restore_page_snapshot_region(mc_mem_region_t region, size_t page_count, uint64_t* pagemap, mc_mem_region_t reference_region)
+/** @brief Restore a snapshot of a region
+ *
+ * If possible, the restoration will be incremental
+ * (the modified pages will not be touched).
+ *
+ * @param start_addr
+ * @param page_count Number of pages of the region
+ * @param pagenos
+ * @param pagemap Linux kernel pagemap values fot this region (or NULL)
+ * @param reference_pages Snapshot page numbers of the previous soft_dirty_reset (or NULL)
+ */
+void mc_restore_page_snapshot_region(mc_process_t process,
+ void* start_addr, size_t page_count, size_t* pagenos, uint64_t* pagemap, size_t* reference_pagenos)
{
for (size_t i=0; i!=page_count; ++i) {
bool softclean = pagemap && !(pagemap[i] & SOFT_DIRTY);
- if (softclean && reference_region && reference_region->page_numbers[i] == region->page_numbers[i]) {
+ if (softclean && reference_pagenos && pagenos[i] == reference_pagenos[i]) {
// The page is softclean and is the same as the reference one:
// the page is already in the target state.
continue;
}
// Otherwise, copy the page:
- void* target_page = mc_page_from_number(region->start_addr, i);
- const void* source_page = mc_model_checker->pages->get_page(region->page_numbers[i]);
- memcpy(target_page, source_page, xbt_pagesize);
+ void* target_page = mc_page_from_number(start_addr, i);
+ const void* source_page = mc_model_checker->pages->get_page(pagenos[i]);
+ MC_process_write(process, source_page, target_page, xbt_pagesize);
}
}
return res;
}
-static inline void mc_ensure_fd(int* fd, const char* path, int flags) {
+static inline __attribute__ ((always_inline))
+void mc_ensure_fd(int* fd, const char* path, int flags) {
if (*fd != -1)
return;
*fd = open(path, flags);
// ***** High level API
-mc_mem_region_t mc_region_new_sparse(int type, void *start_addr, size_t size, mc_mem_region_t ref_reg)
+mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
+ void *start_addr, void* permanent_addr, size_t size,
+ mc_mem_region_t ref_reg)
{
- mc_mem_region_t new_reg = xbt_new(s_mc_mem_region_t, 1);
+ mc_process_t process = &mc_model_checker->process;
- new_reg->start_addr = start_addr;
- new_reg->data = NULL;
- new_reg->size = size;
- new_reg->page_numbers = NULL;
+ mc_mem_region_t region = xbt_new(s_mc_mem_region_t, 1);
+ region->region_type = region_type;
+ region->storage_type = MC_REGION_STORAGE_TYPE_CHUNKED;
+ region->start_addr = start_addr;
+ region->permanent_addr = permanent_addr;
+ region->size = size;
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 = mc_page_count(size);
uint64_t* pagemap = NULL;
- if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot) {
- pagemap = (uint64_t*) mmalloc_no_memset((xbt_mheap_t) mc_heap, sizeof(uint64_t) * page_count);
- mc_read_pagemap(pagemap, mc_page_number(NULL, start_addr), page_count);
+ if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot &&
+ MC_process_is_self(process)) {
+ pagemap = (uint64_t*) mmalloc_no_memset(mc_heap, sizeof(uint64_t) * page_count);
+ mc_read_pagemap(pagemap, mc_page_number(NULL, permanent_addr), page_count);
}
+ size_t* reg_page_numbers = NULL;
+ if (ref_reg!=NULL && ref_reg->storage_type == MC_REGION_STORAGE_TYPE_CHUNKED)
+ reg_page_numbers = ref_reg->chunked.page_numbers;
+
// Take incremental snapshot:
- new_reg->page_numbers = mc_take_page_snapshot_region(start_addr, page_count, pagemap,
- ref_reg==NULL ? NULL : ref_reg->page_numbers);
+ region->chunked.page_numbers = mc_take_page_snapshot_region(process,
+ permanent_addr, page_count, pagemap, reg_page_numbers);
if(pagemap) {
- mfree((xbt_mheap_t) mc_heap, pagemap);
+ mfree(mc_heap, pagemap);
}
- return new_reg;
+ return region;
}
-void mc_region_restore_sparse(mc_mem_region_t reg, mc_mem_region_t ref_reg)
+void mc_region_restore_sparse(mc_process_t process, mc_mem_region_t reg, mc_mem_region_t ref_reg)
{
- xbt_assert((((uintptr_t)reg->start_addr) & (xbt_pagesize-1)) == 0,
+ xbt_assert((((uintptr_t)reg->permanent_addr) & (xbt_pagesize-1)) == 0,
"Not at the beginning of a page");
size_t page_count = mc_page_count(reg->size);
uint64_t* pagemap = NULL;
// Read soft-dirty bits if necessary in order to know which pages have changed:
- if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot) {
- pagemap = (uint64_t*) mmalloc_no_memset((xbt_mheap_t) mc_heap, sizeof(uint64_t) * page_count);
- mc_read_pagemap(pagemap, mc_page_number(NULL, reg->start_addr), page_count);
+ if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot
+ && MC_process_is_self(process)) {
+ pagemap = (uint64_t*) mmalloc_no_memset(mc_heap, sizeof(uint64_t) * page_count);
+ mc_read_pagemap(pagemap, mc_page_number(NULL, reg->permanent_addr), page_count);
}
- // Incremental per-page snapshot restoration:
- mc_restore_page_snapshot_region(reg, page_count, pagemap, ref_reg);
+ // Incremental per-page snapshot restoration:s
+ size_t* reg_page_numbers = NULL;
+ if (ref_reg && ref_reg->storage_type == MC_REGION_STORAGE_TYPE_CHUNKED)
+ reg_page_numbers = ref_reg->chunked.page_numbers;
+
+ mc_restore_page_snapshot_region(process,
+ reg->permanent_addr, page_count, reg->chunked.page_numbers,
+ pagemap, reg_page_numbers);
- // This is funny, the restoration can restore the state of the current heap,
- // if this happen free(pagemap) would free from the wrong heap:
if(pagemap) {
- mfree((xbt_mheap_t) mc_heap, pagemap);
+ free(pagemap);
}
}
