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now it works ok???

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This commit is contained in:
Victor Olin 2023-05-05 17:57:26 +02:00
parent 9adc14780b
commit 93be622863
5 changed files with 959 additions and 74 deletions
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13
src/GC/include/heap.hpp
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@ -4,13 +4,19 @@
#include <stdlib.h>
#include <vector>
#include <unordered_map>
#include <queue>
#include "chunk.hpp"
#include "profiler.hpp"
<<<<<<< HEAD
<<<<<<< HEAD
#define HEAP_SIZE 320//65536
#define FREE_THRESH (uint) 0
=======
#define HEAP_SIZE 16000//65536
#define FREE_THRESH (uint) 100
>>>>>>> c09da8a (now it works ok???)
// #define HEAP_DEBUG
=======
#define HEAP_SIZE 2097152 //256 //65536 //2097152
@ -78,12 +84,11 @@ namespace GC
static bool profiler_enabled();
// static Chunk *get_at(std::vector<Chunk *> &list, size_t n);
void collect();
void collect(uintptr_t *stack_bottom);
void sweep(Heap &heap);
Chunk *try_recycle_chunks(size_t size);
void free(Heap &heap);
void free_overlap(Heap &heap);
void mark(uintptr_t *start, const uintptr_t *end, std::vector<Chunk *> &worklist);
void mark_hash(uintptr_t *start, const uintptr_t *end);
Chunk* find_pointer_hash(uintptr_t *start, const uintptr_t *end);
void create_table();
@ -92,6 +97,10 @@ namespace GC
void mark_step(uintptr_t start, uintptr_t end, std::vector<Chunk *> &worklist);
void mark_range(std::vector<AddrRange *> &ranges, std::vector<Chunk *> &worklist);
void find_roots(uintptr_t *stack_bottom, std::vector<uintptr_t *> &roots);
void mark(std::vector<uintptr_t *> &roots);
void find_chunks(uintptr_t *stack_addr, std::queue<std::pair<uintptr_t, uintptr_t>> &chunk_spaces);
// Temporary
Chunk *try_recycle_chunks_new(size_t size);
void free_overlap_new(Heap &heap);

141
src/GC/lib/heap.cpp
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@ -4,6 +4,8 @@
#include <vector>
<<<<<<< HEAD
#include <chrono>
#include <queue>
#include <set>
#include "heap.hpp"
@ -98,7 +100,8 @@ namespace GC
{
// auto a_ms = to_us(c_start - a_start);
// Profiler::record(AllocStart, a_ms);
heap.collect();
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
heap.collect(stack_bottom);
// If memory is not enough after collect, crash with OOM error
<<<<<<< HEAD
<<<<<<< HEAD
@ -229,7 +232,7 @@ namespace GC
* function is private so that the user cannot trigger
* a collection unneccessarily.
*/
void Heap::collect()
void Heap::collect(uintptr_t *stack_bottom)
{
auto c_start = time_now;
@ -239,22 +242,31 @@ namespace GC
Profiler::record(CollectStart);
// get current stack frame
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(2));
// auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(2));
if (heap.m_stack_top == nullptr)
throw std::runtime_error(std::string("Error: Heap is not initialized, read the docs!"));
uintptr_t *stack_top = heap.m_stack_top;
// uintptr_t *stack_top = heap.m_stack_top;
//auto work_list = heap.m_allocated_chunks;
//mark(stack_bottom, stack_top, work_list);
// Testing mark_hash, previous woking implementation above
create_table();
mark_hash(stack_bottom, stack_top);
// create_table();
// mark_hash(stack_bottom, stack_top);
vector<uintptr_t *> roots;
cout << "\nb4 find_roots\n";
find_roots(stack_bottom, roots);
cout << "b4 mark\n";
mark(roots);
cout << "b4 sweep\n";
sweep(heap);
cout << "b4 free\n";
free(heap);
auto c_end = time_now;
@ -262,6 +274,23 @@ namespace GC
Profiler::record(CollectStart, to_us(c_end - c_start));
}
void Heap::find_roots(uintptr_t *stack_bottom, vector<uintptr_t *> &roots)
{
Heap &heap = Heap::the();
auto stack_top = heap.m_stack_top;
auto heap_bottom = reinterpret_cast<const uintptr_t>(heap.m_heap);
auto heap_top = reinterpret_cast<const uintptr_t>(heap.m_heap + HEAP_SIZE);
while (stack_bottom < stack_top)
{
if (heap_bottom < *stack_bottom && *stack_bottom < heap_top)
{
roots.push_back(stack_bottom);
}
stack_bottom++;
}
}
/**
* Iterates through the stack, if an element on the stack points to a chunk,
* called a root chunk, that chunk is marked (i.e. reachable).
@ -278,68 +307,58 @@ namespace GC
* @param end Pointer to the end of the stack frame.
* @param worklist The currently allocated chunks, which haven't been marked.
*/
void Heap::mark(uintptr_t *start, const uintptr_t* const end, vector<Chunk *> &worklist)
void Heap::mark(vector<uintptr_t *> &roots)
{
// cout << "\nWorklist size: " << worklist.size() << "\n";
Heap &heap = Heap::the();
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
bool prof_enabled = m_profiler_enable;
if (prof_enabled)
Profiler::record(MarkStart);
vector<AddrRange *> rangeWL;
auto iter = roots.begin(), end = roots.end();
// vector<std::pair<uintptr_t, uintptr_t>> chunk_spaces;
std::queue<std::pair<uintptr_t, uintptr_t>> chunk_spaces;
// std::set<uintptr_t> visited_addresses;
// To find adresses thats in the worklist
for (; start <= end; start++)
cout << "b4 find_chunks of roots\n";
while (iter != end)
{
auto it = worklist.begin();
auto stop = worklist.end();
while (it != stop)
find_chunks(*iter++, chunk_spaces);
}
cout << "b4 find_chunks of chunks\n";
while (!chunk_spaces.empty())
{
Chunk *chunk = *it;
auto range = chunk_spaces.front();
chunk_spaces.pop();
auto stack_addr = reinterpret_cast<uintptr_t *>(range.first);
find_chunks(stack_addr, chunk_spaces);
}
}
void Heap::find_chunks(uintptr_t *stack_addr, std::queue<std::pair<uintptr_t, uintptr_t>> &chunk_spaces)
{
auto iter = m_allocated_chunks.begin();
auto end = m_allocated_chunks.end();
while (iter != end)
{
auto chunk = *iter++;
if (chunk->m_marked)
continue;
auto c_start = reinterpret_cast<uintptr_t>(chunk->m_start);
auto c_size = reinterpret_cast<uintptr_t>(chunk->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
// Check if the stack pointer points to something within the chunk
if (c_start <= *start && *start < c_end)
if (c_start < *stack_addr && *stack_addr < c_end)
{
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkMarked, chunk);
chunk->m_marked = true;
it = worklist.erase(it);
/* Chunk *next = find_pointer((uintptr_t *) c_start, (uintptr_t *) c_end, worklist);
while (next != NULL) {
if (!next->m_marked)
{
next->m_marked = true;
auto c_start = reinterpret_cast<uintptr_t>(next->m_start);
auto c_size = reinterpret_cast<uintptr_t>(next->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
next = find_pointer((uintptr_t *) c_start, (uintptr_t *) c_end, worklist);
}
} */
// Recursively call mark, to see if the reachable chunk further points to another chunk
// mark((uintptr_t *)c_start, (uintptr_t *)c_end, worklist);
// AddrRange *range = new AddrRange((uintptr_t *)c_start, (uintptr_t *)c_end);
rangeWL.push_back(new AddrRange((uintptr_t *)c_start, (uintptr_t *)c_end));
}
else
{
++it;
// chunk_spaces.push_back(std::make_pair(c_start, c_end));
chunk_spaces.push(std::make_pair(c_start, c_end));
}
}
else
{
++it;
}
}
}
mark_range(rangeWL, worklist);
rangeWL.clear();
}
<<<<<<< HEAD
@ -518,12 +537,12 @@ namespace GC
Profiler::record(ChunkSwept, chunk);
heap.m_freed_chunks.push_back(chunk);
iter = heap.m_allocated_chunks.erase(iter);
//heap.m_size -= chunk->m_size;
cout << "Decremented total heap size with: " << chunk->m_size << endl;
cout << "Total size is: " << heap.m_size << endl;
heap.m_size -= chunk->m_size;
// cout << "Decremented total heap size with: " << chunk->m_size << endl;
// cout << "Total size is: " << heap.m_size << endl;
}
}
std::cout << "Chunks left: " << heap.m_allocated_chunks.size() << std::endl;
// std::cout << "Chunks left: " << heap.m_allocated_chunks.size() << std::endl;
}
/**
@ -553,9 +572,9 @@ namespace GC
heap.m_freed_chunks.pop_back();
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
heap.m_size -= chunk->m_size;
cout << "Decremented total heap size with: " << chunk->m_size << endl;
cout << "Total size is: " << heap.m_size << endl;
// heap.m_size -= chunk->m_size;
// cout << "Decremented total heap size with: " << chunk->m_size << endl;
// cout << "Total size is: " << heap.m_size << endl;
delete chunk;
}
}

853
src/GC/lib/heap_old.cpp Normal file
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@ -0,0 +1,853 @@
#include <iostream>
#include <stdexcept>
#include <stdlib.h>
#include <vector>
#include <unordered_map>
#include <chrono>
#include "heap.hpp"
#define time_now std::chrono::high_resolution_clock::now()
#define to_us std::chrono::duration_cast<std::chrono::microseconds>
using std::cout, std::endl, std::vector, std::hex, std::dec, std::unordered_map;
namespace GC
{
/**
* This implementation of the() guarantees laziness
* on the instance and a correct destruction with
* the destructor.
*
* @returns The singleton object.
*/
Heap& Heap::the()
{
static Heap instance;
return instance;
}
/**
* Initialises the heap singleton and saves the address
* of the calling function's stack frame as the stack_top.
* Presumeably this address points to the stack frame of
* the compiled LLVM executable after linking.
*/
void Heap::init()
{
Heap &heap = Heap::the();
if (heap.profiler_enabled())
Profiler::record(HeapInit);
// clang complains because arg for __b_f_a is not 0 which is "unsafe"
#pragma clang diagnostic ignored "-Wframe-address"
heap.m_stack_top = static_cast<uintptr_t *>(__builtin_frame_address(1));
// TODO: handle this below
//heap.m_heap_top = heap.m_heap;
}
void Heap::set_profiler_log_options(RecordOption flags)
{
Profiler::set_log_options(flags);
}
/**
* Disposes the heap and the profiler at program exit
* which also triggers a heap log file dumped if the
* profiler is enabled.
*/
void Heap::dispose()
{
Heap &heap = Heap::the();
if (heap.profiler_enabled())
Profiler::dispose();
}
/**
* Allocates a given amount of bytes on the heap.
*
* @param size The amount of bytes to be allocated.
*
* @return A pointer to the address where the memory
* has been allocated. This pointer is supposed
* to be casted to and object pointer.
*/
void *Heap::alloc(size_t size)
{
auto a_start = time_now;
// Singleton
Heap &heap = Heap::the();
bool profiler_enabled = heap.profiler_enabled();
if (profiler_enabled)
Profiler::record(AllocStart, size);
if (size == 0)
{
cout << "Heap: Cannot alloc 0B. No bytes allocated." << endl;
return nullptr;
}
if (heap.m_size + size > HEAP_SIZE)
{
// auto a_ms = to_us(c_start - a_start);
// Profiler::record(AllocStart, a_ms);
heap.collect();
// If memory is not enough after collect, crash with OOM error
if (heap.m_size > HEAP_SIZE)
{
throw std::runtime_error(std::string("Error: Heap out of memory"));
}
//throw std::runtime_error(std::string("Error: Heap out of memory"));
}
if (heap.m_size + size > HEAP_SIZE)
{
if (profiler_enabled)
Profiler::dispose();
throw std::runtime_error(std::string("Error: Heap out of memory"));
}
// If a chunk was recycled, return the old chunk address
Chunk *reused_chunk = heap.try_recycle_chunks(size);
if (reused_chunk != nullptr)
{
if (profiler_enabled)
Profiler::record(ReusedChunk, reused_chunk);
auto a_end = time_now;
auto a_ms = to_us(a_end - a_start);
Profiler::record(AllocStart, a_ms);
return static_cast<void *>(reused_chunk->m_start);
}
// If no free chunks was found (reused_chunk is a nullptr),
// then create a new chunk
auto new_chunk = new Chunk(size, (uintptr_t *)(heap.m_heap + heap.m_size));
heap.m_size += size;
// TODO: handle this below
//heap.m_total_size += size;
heap.m_allocated_chunks.push_back(new_chunk);
if (profiler_enabled)
Profiler::record(NewChunk, new_chunk);
auto a_end = time_now;
auto a_ms = to_us(a_end - a_start);
Profiler::record(AllocStart, a_ms);
return new_chunk->m_start;
}
/**
* Tries to recycle used and freed chunks that are
* already allocated objects by the OS but freed
* from our Heap. This reduces the amount of GC
* objects slightly which saves time from malloc'ing
* memory from the OS.
*
* @param size Amount of bytes needed for the object
* which is about to be allocated.
*
* @returns If a chunk is found and recycled, a
* pointer to the allocated memory for
* the object is returned. If not, a
* nullptr is returned to signify no
* chunks were found.
*/
Chunk *Heap::try_recycle_chunks(size_t size)
{
Heap &heap = Heap::the();
// Check if there are any freed chunks large enough for current request
for (size_t i = 0; i < heap.m_freed_chunks.size(); i++)
{
//auto chunk = Heap::get_at(heap.m_freed_chunks, i);
auto chunk = heap.m_freed_chunks[i];
auto iter = heap.m_freed_chunks.begin();
i++;
//advance(iter, i);
if (chunk->m_size > size)
{
// Split the chunk, use one part and add the remaining part to
// the list of freed chunks
size_t diff = chunk->m_size - size;
auto chunk_complement = new Chunk(diff, chunk->m_start + chunk->m_size);
heap.m_freed_chunks.erase(iter);
heap.m_freed_chunks.push_back(chunk_complement);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
else if (chunk->m_size == size)
{
// Reuse the whole chunk
heap.m_freed_chunks.erase(iter);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
}
// If no chunk was found, return nullptr
return nullptr;
}
/**
* Returns a bool whether the profiler is enabled
* or not.
*
* @returns True or false if the profiler is enabled
* or disabled respectively.
*/
bool Heap::profiler_enabled() {
Heap &heap = Heap::the();
return heap.m_profiler_enable;
}
/**
* Collection phase of the garbage collector. When
* an allocation is requested and there is no space
* left on the heap, a collection is triggered. This
* function is private so that the user cannot trigger
* a collection unneccessarily.
*/
void Heap::collect()
{
auto c_start = time_now;
Heap &heap = Heap::the();
if (heap.profiler_enabled())
Profiler::record(CollectStart);
// get current stack frame
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(2));
if (heap.m_stack_top == nullptr)
throw std::runtime_error(std::string("Error: Heap is not initialized, read the docs!"));
uintptr_t *stack_top = heap.m_stack_top;
//auto work_list = heap.m_allocated_chunks;
//mark(stack_bottom, stack_top, work_list);
// Testing mark_hash, previous woking implementation above
create_table();
mark_hash(stack_bottom, stack_top);
sweep(heap);
free(heap);
auto c_end = time_now;
Profiler::record(CollectStart, to_us(c_end - c_start));
}
/**
* Iterates through the stack, if an element on the stack points to a chunk,
* called a root chunk, that chunk is marked (i.e. reachable).
* Then it recursively follows all chunks which are possibly reachable from
* the root chunk and mark those chunks.
* If a chunk is marked it is removed from the worklist, since it's no longer of
* concern for this method.
*
* Time complexity: 0(N^2 * log(N)) as upper bound.
* Where N is either the size of the worklist or the size of
* the stack frame, depending on which is the largest.
*
* @param start Pointer to the start of the stack frame.
* @param end Pointer to the end of the stack frame.
* @param worklist The currently allocated chunks, which haven't been marked.
*/
void Heap::mark(uintptr_t *start, const uintptr_t* const end, vector<Chunk *> &worklist)
{
// cout << "\nWorklist size: " << worklist.size() << "\n";
Heap &heap = Heap::the();
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
Profiler::record(MarkStart);
vector<AddrRange *> rangeWL;
// To find adresses thats in the worklist
for (; start <= end; start++)
{
auto it = worklist.begin();
auto stop = worklist.end();
while (it != stop)
{
Chunk *chunk = *it;
auto c_start = reinterpret_cast<uintptr_t>(chunk->m_start);
auto c_size = reinterpret_cast<uintptr_t>(chunk->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
// Check if the stack pointer points to something within the chunk
if (c_start <= *start && *start < c_end)
{
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkMarked, chunk);
chunk->m_marked = true;
it = worklist.erase(it);
/* Chunk *next = find_pointer((uintptr_t *) c_start, (uintptr_t *) c_end, worklist);
while (next != NULL) {
if (!next->m_marked)
{
next->m_marked = true;
auto c_start = reinterpret_cast<uintptr_t>(next->m_start);
auto c_size = reinterpret_cast<uintptr_t>(next->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
next = find_pointer((uintptr_t *) c_start, (uintptr_t *) c_end, worklist);
}
} */
// Recursively call mark, to see if the reachable chunk further points to another chunk
// mark((uintptr_t *)c_start, (uintptr_t *)c_end, worklist);
// AddrRange *range = new AddrRange((uintptr_t *)c_start, (uintptr_t *)c_end);
rangeWL.push_back(new AddrRange((uintptr_t *)c_start, (uintptr_t *)c_end));
}
else
{
++it;
}
}
else
{
++it;
}
}
}
mark_range(rangeWL, worklist);
rangeWL.clear();
}
void Heap::mark_range(vector<AddrRange *> &ranges, vector<Chunk *> &worklist)
{
Heap &heap = Heap::the();
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
Profiler::record(MarkStart);
auto iter = ranges.begin();
auto stop = ranges.end();
while (iter != stop)
{
auto range = *iter++;
uintptr_t *start = (uintptr_t *)range->start;
const uintptr_t *end = range->end;
if (start == nullptr)
cout << "\nstart is null\n";
for (; start <= end; start++)
{
auto wliter = worklist.begin();
auto wlstop = worklist.end();
while (wliter != wlstop)
{
Chunk *chunk = *wliter;
auto c_start = reinterpret_cast<uintptr_t>(chunk->m_start);
auto c_size = reinterpret_cast<uintptr_t>(chunk->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
if (c_start <= *start && *start < c_end)
{
if (!chunk->m_marked)
{
chunk->m_marked = true;
wliter = worklist.erase(wliter);
ranges.push_back(new AddrRange((uintptr_t *)c_start, (uintptr_t *)c_end));
stop = ranges.end();
}
else
{
wliter++;
}
}
else
{
wliter++;
}
}
}
}
}
void Heap::create_table()
{
Heap &heap = Heap::the();
unordered_map<uintptr_t, Chunk*> chunk_table;
for (auto chunk : heap.m_allocated_chunks) {
auto pair = std::make_pair(reinterpret_cast<uintptr_t>(chunk->m_start), chunk);
heap.m_chunk_table.insert(pair);
}
}
void Heap::mark_hash(uintptr_t *start, const uintptr_t* const end)
{
Heap &heap = Heap::the();
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
Profiler::record(MarkStart);
for (; start <= end; start++)
{
auto search = heap.m_chunk_table.find(*start);
if (search != heap.m_chunk_table.end())
{
Chunk *chunk = search->second;
auto c_start = reinterpret_cast<uintptr_t>(chunk->m_start);
auto c_size = reinterpret_cast<uintptr_t>(chunk->m_size);
auto c_end = reinterpret_cast<uintptr_t*>(c_start + c_size);
if (!chunk->m_marked)
{
chunk->m_marked = true;
if (profiler_enabled)
Profiler::record(ChunkMarked, chunk);
//mark_hash(chunk->m_start, c_end);
Chunk *next = find_pointer_hash((uintptr_t *) c_start, (uintptr_t *) c_end);
while (next != NULL)
{
if (!next->m_marked)
{
next->m_marked = true;
if (profiler_enabled)
Profiler::record(ChunkMarked, chunk);
auto c_start = reinterpret_cast<uintptr_t>(next->m_start);
auto c_size = reinterpret_cast<uintptr_t>(next->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
next = find_pointer_hash((uintptr_t *) c_start, (uintptr_t *) c_end);
}
}
}
}
}
}
/**
* Sweeps the heap, unmarks the marked chunks for the next cycle,
* adds the unmarked nodes to the list of freed chunks; to be freed.
*
* Time complexity: O(N^2), where N is the number of allocated chunks.
* It is quadratic, in the worst case,
* since each call to erase() is linear.
*
* @param heap Pointer to the heap singleton instance.
*/
void Heap::sweep(Heap &heap)
{
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
Profiler::record(SweepStart);
auto iter = heap.m_allocated_chunks.begin();
std::cout << "Chunks alloced: " << heap.m_allocated_chunks.size() << std::endl;
// This cannot "iter != stop", results in seg fault, since the end gets updated, I think.
while (iter != heap.m_allocated_chunks.end())
{
Chunk *chunk = *iter;
// Unmark the marked chunks for the next iteration.
if (chunk->m_marked)
{
chunk->m_marked = false;
++iter;
}
else
{
// Add the unmarked chunks to freed chunks and remove from
// the list of allocated chunks
if (profiler_enabled)
Profiler::record(ChunkSwept, chunk);
heap.m_freed_chunks.push_back(chunk);
iter = heap.m_allocated_chunks.erase(iter);
//heap.m_size -= chunk->m_size;
cout << "Decremented total heap size with: " << chunk->m_size << endl;
cout << "Total size is: " << heap.m_size << endl;
}
}
std::cout << "Chunks left: " << heap.m_allocated_chunks.size() << std::endl;
}
/**
* Frees chunks that was moved to the list m_freed_chunks
* by the sweep phase. If there are more than a certain
* amount of free chunks, delete the free chunks to
* avoid cluttering.
*
* Time complexity: O(N^2), where N is the freed chunks.
* If free_overlap() is called, it runs in O(N^2),
* otherwise O(N).
*
* @param heap Heap singleton instance, only for avoiding
* redundant calls to the singleton get
*/
void Heap::free(Heap &heap)
{
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
Profiler::record(FreeStart);
if (heap.m_freed_chunks.size() > FREE_THRESH)
{
bool profiler_enabled = heap.profiler_enabled();
while (heap.m_freed_chunks.size())
{
auto chunk = heap.m_freed_chunks.back();
heap.m_freed_chunks.pop_back();
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
heap.m_size -= chunk->m_size;
cout << "Decremented total heap size with: " << chunk->m_size << endl;
cout << "Total size is: " << heap.m_size << endl;
delete chunk;
}
}
// if there are chunks but not more than FREE_THRESH
else if (heap.m_freed_chunks.size())
{
// essentially, always check for overlap between
// chunks before finishing the allocation
free_overlap(heap);
}
}
/**
* Checks for overlaps between freed chunks of memory
* and removes overlapping chunks while prioritizing
* the chunks at lower addresses.
*
* Time complexity: O(N^2), where N is the number of freed chunks.
* At each iteration get_at() is called, which is linear.
*
* @param heap Heap singleton instance, only for avoiding
* redundant calls to the singleton get
*
* @note Maybe this should be changed to prioritizing
* larger chunks. Should remove get_at() to indexing,
* since that's constant.
*/
void Heap::free_overlap(Heap &heap) // borde göra en record(ChunkFreed) på onödiga chunks
{
std::vector<Chunk *> filtered;
size_t i = 0;
//auto prev = Heap::get_at(heap.m_freed_chunks, i++);
auto prev = heap.m_freed_chunks[i++];
prev->m_marked = true;
filtered.push_back(prev);
// cout << filtered.back()->m_start << endl;
for (; i < heap.m_freed_chunks.size(); i++)
{
prev = filtered.back();
//auto next = Heap::get_at(heap.m_freed_chunks, i);
auto next = heap.m_freed_chunks[i];
auto p_start = (uintptr_t)(prev->m_start);
auto p_size = (uintptr_t)(prev->m_size);
auto n_start = (uintptr_t)(next->m_start);
if (n_start >= (p_start + p_size))
{
next->m_marked = true;
filtered.push_back(next);
}
}
heap.m_freed_chunks.swap(filtered);
bool profiler_enabled = heap.m_profiler_enable;
// After swap m_freed_chunks contains still available chunks
// and filtered contains all the chunks, so delete unused chunks
for (Chunk *chunk : filtered)
{
// if chunk was filtered away, delete it
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
heap.m_size -= chunk->m_size;
cout << "Decremented total heap size with: " << chunk->m_size << endl;
cout << "Total size is: " << heap.m_size << endl;
delete chunk;
}
else
{
chunk->m_marked = false;
}
}
}
void Heap::set_profiler(bool mode)
{
Heap &heap = Heap::the();
heap.m_profiler_enable = mode;
}
Chunk* find_pointer(uintptr_t *start, const uintptr_t* const end, vector<Chunk *> &worklist) {
for (; start <= end; start++) {
auto it = worklist.begin();
auto stop = worklist.end();
while (it != stop)
{
Chunk *chunk = *it;
auto c_start = reinterpret_cast<uintptr_t>(chunk->m_start);
auto c_size = reinterpret_cast<uintptr_t>(chunk->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
// Check if the stack pointer points to something within the chunk
if (c_start <= *start && *start < c_end)
{
return chunk;
}
return NULL;
}
}
}
// Checks if a given chunk points to another chunk and returns it
Chunk* Heap::find_pointer_hash(uintptr_t *start, const uintptr_t* const end) {
Heap &heap = Heap::the();
for (; start <= end; start++) {
auto search = heap.m_chunk_table.find(*start);
if (search != heap.m_chunk_table.end()) {
return search->second;
}
return NULL;
}
}
#ifdef HEAP_DEBUG
/**
* Prints the result of Heap::init() and a dummy value
* for the current stack frame for reference.
*/
void Heap::check_init()
{
Heap &heap = Heap::the();
cout << "Heap addr:\t" << &heap << "\n";
cout << "GC m_stack_top:\t" << heap.m_stack_top << "\n";
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
cout << "GC stack_bottom:\t" << stack_bottom << endl;
}
/**
* Conditional collection, only to be used in debugging
*
* @param flags Bitmap of flags
*/
void Heap::collect(CollectOption flags)
{
set_profiler(true);
Heap &heap = Heap::the();
if (heap.m_profiler_enable)
Profiler::record(CollectStart);
cout << "DEBUG COLLECT\nFLAGS: ";
if (flags & MARK)
cout << "\n - MARK";
if (flags & SWEEP)
cout << "\n - SWEEP";
if (flags & FREE)
cout << "\n - FREE";
cout << "\n";
// get the frame adress, whwere local variables and saved registers are located
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
cout << "Stack bottom in collect:\t" << stack_bottom << "\n";
uintptr_t *stack_top = heap.m_stack_top;
cout << "Stack end in collect:\t " << stack_top << endl;
auto work_list = heap.m_allocated_chunks;
if (flags & MARK)
mark(stack_bottom, stack_top, work_list);
if (flags & SWEEP)
sweep(heap);
if (flags & FREE)
free(heap);
}
// Mark child references from the root references
void mark_test(vector<Chunk *> &worklist)
{
while (worklist.size() > 0)
{
Chunk *ref = worklist.back();
worklist.pop_back();
Chunk *child = (Chunk *)ref; // this is probably not correct
if (child != nullptr && !child->m_marked)
{
child->m_marked = true;
worklist.push_back(child);
mark_test(worklist);
}
}
}
// Mark the root references and look for child references to them
void mark_from_roots(uintptr_t *start, const uintptr_t *end)
{
vector<Chunk *> worklist;
for (; start > end; start--)
{
if (*start % 8 == 0)
{ // all pointers must be aligned as double words
Chunk *ref = (Chunk *)*start;
if (ref != nullptr && !ref->m_marked)
{
ref->m_marked = true;
worklist.push_back(ref);
mark_test(worklist);
}
}
}
}
// For testing purposes
void Heap::print_line(Chunk *chunk)
{
cout << "Marked: " << chunk->m_marked << "\nStart adr: " << chunk->m_start << "\nSize: " << chunk->m_size << " B\n"
<< endl;
}
void Heap::print_worklist(std::vector<Chunk *> &list)
{
for (auto cp : list)
cout << "Chunk at:\t" << cp->m_start << "\nSize:\t\t" << cp->m_size << "\n";
cout << endl;
}
void Heap::print_contents()
{
Heap &heap = Heap::the();
if (heap.m_allocated_chunks.size())
{
cout << "\nALLOCATED CHUNKS #" << dec << heap.m_allocated_chunks.size() << endl;
for (auto chunk : heap.m_allocated_chunks)
print_line(chunk);
}
else
{
cout << "NO ALLOCATIONS\n" << endl;
}
if (heap.m_freed_chunks.size())
{
cout << "\nFREED CHUNKS #" << dec << heap.m_freed_chunks.size() << endl;
for (auto fchunk : heap.m_freed_chunks)
print_line(fchunk);
}
else
{
cout << "NO FREED CHUNKS" << endl;
}
}
void Heap::print_summary()
{
Heap &heap = Heap::the();
if (heap.m_allocated_chunks.size())
{
cout << "\nALLOCATED CHUNKS #" << dec << heap.m_allocated_chunks.size() << endl;
}
else
{
cout << "NO ALLOCATIONS\n" << endl;
}
if (heap.m_freed_chunks.size())
{
cout << "\nFREED CHUNKS #" << dec << heap.m_freed_chunks.size() << endl;
}
else
{
cout << "NO FREED CHUNKS" << endl;
}
}
void Heap::print_allocated_chunks(Heap *heap) {
cout << "--- Allocated Chunks ---\n" << endl;
for (auto chunk : heap->m_allocated_chunks) {
print_line(chunk);
}
}
Chunk *Heap::try_recycle_chunks_new(size_t size)
{
Heap &heap = Heap::the();
// Check if there are any freed chunks large enough for current request
for (size_t i = 0; i < heap.m_freed_chunks.size(); i++)
{
auto chunk = heap.m_freed_chunks[i]; //Heap::get_at(heap.m_freed_chunks, i);
auto iter = heap.m_freed_chunks.begin();
//advance(iter, i);
i++;
if (chunk->m_size > size)
{
// Split the chunk, use one part and add the remaining part to
// the list of freed chunks
size_t diff = chunk->m_size - size;
auto chunk_complement = new Chunk(diff, chunk->m_start + chunk->m_size);
heap.m_freed_chunks.erase(iter);
heap.m_freed_chunks.push_back(chunk_complement);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
else if (chunk->m_size == size)
{
// Reuse the whole chunk
heap.m_freed_chunks.erase(iter);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
}
// If no chunk was found, return nullptr
return nullptr;
}
void Heap::free_overlap_new(Heap &heap) // borde göra en record(ChunkFreed) på onödiga chunks
{
std::vector<Chunk *> filtered;
size_t i = 0;
auto prev = heap.m_freed_chunks[i++]; //Heap::get_at(heap.m_freed_chunks, i++);
prev->m_marked = true;
filtered.push_back(prev);
cout << filtered.back()->m_start << endl;
for (; i < heap.m_freed_chunks.size(); i++)
{
prev = filtered.back();
auto next = heap.m_freed_chunks[i]; //Heap::get_at(heap.m_freed_chunks, i);
auto p_start = (uintptr_t)(prev->m_start);
auto p_size = (uintptr_t)(prev->m_size);
auto n_start = (uintptr_t)(next->m_start);
if (n_start >= (p_start + p_size))
{
next->m_marked = true;
filtered.push_back(next);
}
}
heap.m_freed_chunks.swap(filtered);
bool profiler_enabled = heap.m_profiler_enable;
// After swap m_freed_chunks contains still available chunks
// and filtered contains all the chunks, so delete unused chunks
for (Chunk *chunk : filtered)
{
// if chunk was filtered away, delete it
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
delete chunk;
}
else
{
chunk->m_marked = false;
}
}
}
#endif
}

2
src/GC/lib/profiler.cpp
View file

@ -11,7 +11,7 @@
#include "event.hpp"
#include "profiler.hpp"
#define MAC_OS
// #define MAC_OS
namespace GC
{

8
src/GC/tests/linkedlist.cpp
View file

@ -53,7 +53,7 @@ void clear_list(Node *head)
}
}
#define LIST_SIZE 10
#define LIST_SIZE 1000
void list_test1()
{
@ -61,6 +61,7 @@ void list_test1()
// print_list(list_1);
}
/*
void list_test2()
{
Node *list_2 = create_list(LIST_SIZE);
@ -99,6 +100,7 @@ void make_test() {
list_test5();
list_test6();
}
*/
int main()
{
@ -108,7 +110,9 @@ int main()
GC::Profiler::set_log_options(GC::FunctionCalls);
//GC::Profiler::set_log_options(GC::AllOps);
make_test();
// make_test();
for (int i = 0; i < 1000; i++)
list_test1();
GC::Heap::dispose();