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fix treeallocator bug and reenable

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This commit is contained in:
Christoph Urlacher
2022-07-04 14:54:14 +02:00
parent 455c9c5557
commit 7fe5d8e956
3 changed files with 10 additions and 7 deletions
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4
c_os/kernel/Globals.cc
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@ -17,9 +17,9 @@ Keyboard kb; // Tastatur
IntDispatcher intdis; // Unterbrechungsverteilung
PIC pic; // Interrupt-Controller
unsigned int total_mem; // RAM total
BumpAllocator allocator;
// BumpAllocator allocator;
// LinkedListAllocator allocator;
// TreeAllocator allocator;
TreeAllocator allocator;
Scheduler scheduler;
BIOS bios; // Schnittstelle zum 16-Bit BIOS
VESA vesa; // VESA-Treiber

4
c_os/kernel/Globals.h
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@ -30,9 +30,9 @@ extern Keyboard kb; // Tastatur
extern IntDispatcher intdis; // Unterbrechungsverteilung
extern PIC pic; // Interrupt-Controller
extern unsigned int total_mem; // RAM total
extern BumpAllocator allocator;
// extern BumpAllocator allocator;
// extern LinkedListAllocator allocator;
// extern TreeAllocator allocator;
extern TreeAllocator allocator;
extern Scheduler scheduler;
extern BIOS bios; // Schnittstelle zum 16-Bit BIOS
extern VESA vesa; // VESA-Treiber

9
c_os/kernel/allocator/TreeAllocator.cc
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@ -10,6 +10,7 @@ void TreeAllocator::init() {
this->free_start->left = NULL;
this->free_start->right = NULL;
this->free_start->parent = NULL;
this->free_start->red = false; // The root is always black
this->free_start->next = (list_block_t*)this->free_start;
this->free_start->previous = (list_block_t*)this->free_start;
@ -59,9 +60,6 @@ void* TreeAllocator::alloc(unsigned int req_size) {
unsigned int size = this->get_size(best_fit);
if constexpr (DEBUG) { kout << " - Found best-fit: " << hex << (unsigned int)best_fit << endl; }
// Remove the block first so we can insert correctly when cutting
// kout << " - Removing block from freelist" << endl;
this->rbt_remove(best_fit);
if (size > HEAP_MIN_FREE_BLOCK_SIZE + rreq_size + sizeof(list_block_t)) {
// Block can be cut
if constexpr (DEBUG) { kout << " - Allocating " << dec << rreq_size << " Bytes with cutting" << endl; }
@ -77,6 +75,11 @@ void* TreeAllocator::alloc(unsigned int req_size) {
// need to remove it from the freelist, which is done for both cases
if constexpr (DEBUG) { kout << " - Allocating " << dec << rreq_size << " Bytes without cutting" << endl; }
}
// Remove the old block from the freelist
// BUG: If the first allocation allocates the whole heap, this removal will crash the paging
// as the freelist will no longer contain any notes, gives NullPointerException as it's not handled
// kout << " - Removing block from freelist" << endl;
this->rbt_remove(best_fit);
if constexpr (DEBUG) { kout << " - Returned address " << hex << (unsigned int)((char*)best_fit + sizeof(list_block_t)) << endl; }
return (void*)((char*)best_fit + sizeof(list_block_t));