* 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>
-
-#include <boost/foreach.hpp>
-
-#include <xbt.h>
-
-#include "PageStore.hpp"
-
-#ifdef MC_PAGE_STORE_MD4
-#include <nettle/md4.h>
+#ifdef __FreeBSD__
+# define MAP_POPULATE MAP_PREFAULT_READ
#endif
-#include "mc_mmu.h"
+#include <xbt/base.h>
+#include <xbt/log.h>
+#include <xbt/sysdep.h>
-extern "C" {
+#include "src/mc/PageStore.hpp"
+
+#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.
static inline __attribute__ ((always_inline))
PageStore::hash_type mc_hash_page(const void* data)
{
-#ifdef MC_PAGE_STORE_MD4
- boost::array<uint64_t,2> result;
- md4_ctx context;
- md4_init(&context);
- md4_update(&context, xbt_pagesize, (const uint8_t*) data);
- md4_digest(&context, MD4_DIGEST_SIZE, (uint8_t*) &(result[0]));
- return result;
-#else
- const uint64_t* values = (const uint64_t*) data;
- size_t n = xbt_pagesize / sizeof(uint64_t);
+ const std::uint64_t* values = (const uint64_t*) data;
+ std::size_t n = xbt_pagesize / sizeof(uint64_t);
// This djb2:
- uint64_t hash = 5381;
- for (size_t i=0; i!=n; ++i) {
+ std::uint64_t hash = 5381;
+ for (std::size_t i = 0; i != n; ++i)
hash = ((hash << 5) + hash) + values[i];
- }
return hash;
-#endif
}
// ***** 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;
::munmap(this->memory_, this->capacity_ << xbt_pagebits);
}
-void PageStore::resize(size_t size)
+void PageStore::resize(std::size_t 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;
*
* @return index of the free page
*/
-size_t PageStore::alloc_page()
+std::size_t PageStore::alloc_page()
{
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_++;
}
}
-void PageStore::remove_page(size_t pageno)
+void PageStore::remove_page(std::size_t pageno)
{
this->free_pages_.push_back(pageno);
const void* page = this->get_page(pageno);
hash_type hash = mc_hash_page(page);
-#ifdef MC_PAGE_STORE_MD4
- this->hash_index_.erase(hash);
-#else
this->hash_index_[hash].erase(pageno);
-#endif
}
/** Store a page in memory */
-size_t PageStore::store_page(void* page)
+std::size_t PageStore::store_page(void* page)
{
xbt_assert(top_index_ <= this->capacity_, "top_index is not consistent");
// 2. find pages with the same hash using `hash_index_`;
// 3. find a page with the same content.
hash_type hash = mc_hash_page(page);
-#ifdef MC_PAGE_STORE_MD4
- s_mc_pages_store::pages_map_type::const_iterator i =
- this->hash_index_.find(hash);
- if (i!=this->hash_index_.cend()) {
- // If a page with the same content is already in the page store it is
- // reused and its reference count is incremented.
- size_t pageno = i->second;
- page_counts_[pageno]++;
- return pageno;
- }
-#else
// Try to find a duplicate in set of pages with the same hash:
page_set_type& page_set = this->hash_index_[hash];
- BOOST_FOREACH (size_t pageno, page_set) {
+ for (size_t pageno : page_set) {
const void* snapshot_page = this->get_page(pageno);
if (memcmp(page, snapshot_page, xbt_pagesize) == 0) {
}
}
-#endif
// Otherwise, a new page is allocated in the page store and the content
// of the page is `memcpy()`-ed to this new page.
- size_t pageno = alloc_page();
+ std::size_t pageno = alloc_page();
xbt_assert(this->page_counts_[pageno]==0, "Allocated page is already used");
void* snapshot_page = (void*) this->get_page(pageno);
memcpy(snapshot_page, page, xbt_pagesize);
-#ifdef MC_PAGE_STORE_MD4
- this->hash_index_[hash] = pageno;
-#else
page_set.insert(pageno);
-#endif
page_counts_[pageno]++;
return pageno;
}
#ifdef SIMGRID_TEST
-#include <string.h>
-#include <stdlib.h>
-#include <stdint.h>
+#include <cstring>
+#include <cstdint>
+
#include <unistd.h>
#include <sys/mman.h>
#include <memory>
-#include "mc/PageStore.hpp"
+#include "src/mc/PageStore.hpp"
static int value = 0;
-static void new_content(void* data, size_t size)
+static void new_content(void* data, std::size_t size)
{
- memset(data, ++value, size);
+ ::memset(data, ++value, size);
}
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")
{
+ using simgrid::mc::PageStore;
+
xbt_test_add("Init");
- size_t pagesize = (size_t) getpagesize();
- std::unique_ptr<simgrid::mc::PageStore> store
- = std::unique_ptr<simgrid::mc::PageStore>(new simgrid::mc::PageStore(500));
+ std::size_t pagesize = (size_t) getpagesize();
+ std::unique_ptr<PageStore> store
+ = std::unique_ptr<PageStore>(new simgrid::mc::PageStore(500));
void* data = getpage();
xbt_test_assert(store->size()==0, "Bad size");
size_t pageno1 = store->store_page(data);
xbt_test_assert(store->get_ref(pageno1)==1, "Bad refcount");
const void* copy = store->get_page(pageno1);
- xbt_test_assert(memcmp(data, copy, pagesize)==0, "Page data should be the same");
+ xbt_test_assert(::memcmp(data, copy, pagesize)==0, "Page data should be the same");
xbt_test_assert(store->size()==1, "Bad size");
xbt_test_add("Store the same page again");
xbt_test_assert(store->size()==2, "Bad size");
}
-}
-
#endif /* SIMGRID_TEST */
-
-}
