X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/d098dd9e12ee321b061421f535b2b56ce7691673..2807fde4fd1f59c230d69a934634c5dfb77905f2:/src/mc/PageStore.cpp diff --git a/src/mc/PageStore.cpp b/src/mc/PageStore.cpp index 403ef31c42..5f2d921689 100644 --- a/src/mc/PageStore.cpp +++ b/src/mc/PageStore.cpp @@ -1,29 +1,33 @@ -/* 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 // memcpy, memcmp #include -#include // memcpy, memcp #include +#ifdef __FreeBSD__ +# define MAP_POPULATE MAP_PREFAULT_READ +#endif -#include +#include "xbt/base.h" +#include "xbt/log.h" +#include "xbt/sysdep.h" -#include "src/mc/PageStore.hpp" +#include "src/internal_config.h" -#include "src/mc/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. @@ -31,35 +35,28 @@ namespace mc { * @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); } @@ -73,13 +70,46 @@ 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; @@ -95,10 +125,9 @@ 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_++; @@ -109,7 +138,6 @@ std::size_t PageStore::alloc_page() size_t res = this->free_pages_[this->free_pages_.size() - 1]; this->free_pages_.pop_back(); return res; - } } @@ -126,29 +154,26 @@ std::size_t PageStore::store_page(void* page) { 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); @@ -171,7 +196,7 @@ std::size_t PageStore::store_page(void* page) #include -#include "mc/PageStore.hpp" +#include "src/mc/PageStore.hpp" static int value = 0; @@ -182,21 +207,18 @@ static void new_content(void* data, std::size_t 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"); std::size_t pagesize = (size_t) getpagesize(); - std::unique_ptr store - = std::unique_ptr(new simgrid::mc::PageStore(500)); + std::unique_ptr store = std::unique_ptr(new simgrid::mc::PageStore(500)); void* data = getpage(); xbt_test_assert(store->size()==0, "Bad size"); @@ -235,8 +257,4 @@ XBT_TEST_UNIT("base", test_mc_page_store, "Test adding/removing pages in the sto xbt_test_assert(store->size()==2, "Bad size"); } -} - #endif /* SIMGRID_TEST */ - -}