-/* Copyright (c) 2015. The SimGrid Team.
+/* Copyright (c) 2015-2017. The SimGrid Team.
* All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
+#include <cstring> // memcpy, memcmp
#include <unistd.h>
-#include <string.h> // memcpy, memcp
#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.hpp"
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_page_snapshot, mc,
- "Logging specific to mc_page_snapshot");
+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.
* @param data Memory page
* @return hash off the page
*/
-static inline __attribute__ ((always_inline))
-PageStore::hash_type mc_hash_page(const void* data)
+static XBT_ALWAYS_INLINE PageStore::hash_type mc_hash_page(const void* data)
{
const std::uint64_t* values = (const uint64_t*) data;
std::size_t n = xbt_pagesize / sizeof(uint64_t);
// 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)
+PageStore::PageStore(size_t size) : memory_(nullptr), capacity_(size), 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) {
+ // Using mmap in order to be able to expand the region by relocating it somewhere else in the virtual memory space:
+ 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;
this->memory_ = memory;
this->page_counts_.resize(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_++;
size_t res = this->free_pages_[this->free_pages_.size() - 1];
this->free_pages_.pop_back();
return res;
-
}
}
{
xbt_assert(top_index_ <= this->capacity_, "top_index is not consistent");
- // First, we check if a page with the same content is already in the page
- // store:
- // 1. compute the hash of the page;
- // 2. find pages with the same hash using `hash_index_`;
- // 3. find a page with the same content.
+ // First, we check if a page with the same content is already in the page store:
+ // 1. compute the hash of the page
+ // 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);
// Try to find a duplicate in set of pages with the same hash:
page_set_type& page_set = this->hash_index_[hash];
- for (size_t pageno : page_set) {
+ for (size_t const& pageno : page_set) {
const void* snapshot_page = this->get_page(pageno);
if (memcmp(page, snapshot_page, xbt_pagesize) == 0) {
- // If a page with the same content is already in the page store it is
- // reused and its reference count is incremented.
+ // If a page with the same content is already in the page store it's reused and its refcount is incremented.
page_counts_[pageno]++;
return pageno;
}
}
- // Otherwise, a new page is allocated in the page store and the content
- // of the page is `memcpy()`-ed to this new page.
+ // Otherwise, a new page is allocated in the page store and the content of the page is `memcpy()`-ed to this new 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);
#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")
{
using simgrid::mc::PageStore;
-
+
xbt_test_add("Init");
std::size_t pagesize = (size_t) getpagesize();
- std::unique_ptr<PageStore> store
- = std::unique_ptr<PageStore>(new simgrid::mc::PageStore(500));
+ 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");
xbt_test_assert(store->size()==2, "Bad size");
}
-}
-
#endif /* SIMGRID_TEST */
-
-}