* under the terms of the license (GNU LGPL) which comes with this package. */
#include <unistd.h>
-#include <string.h> // memcpy, memcp
+#include <string.h> // memcpy, memcmp
#include <sys/mman.h>
+#ifdef __FreeBSD__
+# define MAP_POPULATE MAP_PREFAULT_READ
+#endif
-#include <xbt.h>
+#include <xbt/base.h>
+#include <xbt/log.h>
+#include <xbt/sysdep.h>
-#include "PageStore.hpp"
+#include "src/internal_config.h"
-#include "mc_mmu.h"
+#include "src/mc/PageStore.hpp"
-extern "C" {
+#include "src/mc/mc_mmu.h"
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_page_snapshot, mc,
"Logging specific to mc_page_snapshot");
namespace simgrid {
namespace mc {
-/** @brief Compte a hash for the given memory page
+/** @brief Compute a hash for the given memory page
*
* The page is used before inserting the page in the page store
* in order to find duplicate of this page in the page store.
// This djb2:
std::uint64_t hash = 5381;
- for (std::size_t i = 0; i != n; ++i) {
+ for (std::size_t i = 0; i != n; ++i)
hash = ((hash << 5) + hash) + values[i];
- }
return hash;
}
// ***** snapshot_page_manager
PageStore::PageStore(size_t size) :
- memory_(NULL), capacity_(0), top_index_(0)
+ memory_(nullptr), capacity_(0), top_index_(0)
{
// Using mmap in order to be able to expand the region
// by relocating it somewhere else in the virtual memory
// space:
- void* memory = ::mmap(NULL, size << xbt_pagebits, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE, -1, 0);
- if (memory == MAP_FAILED) {
+ void* memory = ::mmap(nullptr, size << xbt_pagebits, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE, -1, 0);
+ if (memory == MAP_FAILED)
xbt_die("Could not mmap initial snapshot pages.");
- }
this->top_index_ = 0;
this->capacity_ = size;
{
size_t old_bytesize = this->capacity_ << xbt_pagebits;
size_t new_bytesize = size << xbt_pagebits;
+ void *new_memory;
// Expand the memory region by moving it into another
// virtual memory address if necessary:
- void* new_memory = mremap(this->memory_, old_bytesize, new_bytesize, MREMAP_MAYMOVE);
- if (new_memory == MAP_FAILED) {
+#if HAVE_MREMAP
+ new_memory = mremap(this->memory_, old_bytesize, new_bytesize, MREMAP_MAYMOVE);
+ if (new_memory == MAP_FAILED)
xbt_die("Could not mremap snapshot pages.");
+#else
+ if (new_bytesize > old_bytesize) {
+ // Grow: first try to add new space after current map
+ new_memory = mmap((char *)this->memory_ + old_bytesize,
+ new_bytesize-old_bytesize,
+ PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE,
+ -1, 0);
+ if (new_memory == MAP_FAILED)
+ xbt_die("Could not mremap snapshot pages.");
+ // Check if expanding worked
+ if (new_memory != (char *)this->memory_ + old_bytesize) {
+ // New memory segment could not be put at the end of this->memory_,
+ // so cancel this one and try to rellocate everything and copy data
+ munmap(new_memory, new_bytesize-old_bytesize);
+ new_memory = mmap(nullptr,
+ new_bytesize,
+ PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANONYMOUS|MAP_POPULATE,
+ -1, 0);
+ if (new_memory == MAP_FAILED)
+ xbt_die("Could not mremap snapshot pages.");
+ memcpy(new_memory, this->memory_, old_bytesize);
+ munmap(this->memory_, old_bytesize);
+ }
}
+ else {
+ // We don't have functions to shrink a mapping, so leave memory as
+ // it is for now
+ new_memory = this->memory_;
+ }
+#endif
this->capacity_ = size;
this->memory_ = new_memory;
if (this->free_pages_.empty()) {
// Expand the region:
- if (this->top_index_ == this->capacity_) {
+ if (this->top_index_ == this->capacity_)
// All the pages are allocated, we need add more pages:
this->resize(2 * this->capacity_);
- }
// Use a page from the top:
return this->top_index_++;
#include <memory>
-#include "mc/PageStore.hpp"
+#include "src/mc/PageStore.hpp"
static int value = 0;
static void* getpage()
{
- return mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ return mmap(nullptr, getpagesize(), PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
}
-extern "C" {
-
XBT_TEST_SUITE("mc_page_store", "Page store");
XBT_TEST_UNIT("base", test_mc_page_store, "Test adding/removing pages in the store")
xbt_test_assert(store->size()==2, "Bad size");
}
-}
-
#endif /* SIMGRID_TEST */
-
-}