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switch to linked list for alloc

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This commit is contained in:
Eggert Jung
2026-02-23 15:13:47 +01:00
parent 50a4189bde
commit 8d157e1bcd
1 changed files with 31 additions and 29 deletions
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60
kernel/memory/pageframealloc.cc
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@@ -10,6 +10,8 @@
//uint8_t PageFrameAllocator::bitmap[4294967296 / 4096 / 8];
PageFrame PageFrameAllocator::PageFrames[4294967296 / 4096];
Queue<PageFrame> user_memory_q;
Queue<PageFrame> kernel_memory_q;
void mark_pageframes(uintptr_t start, uintptr_t end, bool available){
// DBG << "start: " << hex << start << " end: " << end;
@@ -19,16 +21,24 @@ void mark_pageframes(uintptr_t start, uintptr_t end, bool available){
start = 4294967296;
if(end > 4294967296)
end = 4294967296;
if(start < 0x4000000 && end > 0x4000000){
mark_pageframes(start, 0x4000000, available);
mark_pageframes(0x4000000, end, available);
}
//DBG << " page start: " << hex << start << " end: " << end << endl;
Queue<PageFrame>* q = start<0x4000000?&kernel_memory_q:&user_memory_q;
for(uint64_t i = start; i < end; i += 4096){
uint64_t pg = i/4096;
PageFrameAllocator::PageFrames[pg].available = available;
//if(available)
// PageFrameAllocator::bitmap[pg/8] |= (1 << pg%8);
//else
// PageFrameAllocator::bitmap[pg/8] &= ~(1 << pg%8);
if(available)
q->enqueue(PageFrameAllocator::PageFrames[pg]);
else
q->remove(&PageFrameAllocator::PageFrames[pg]);
}
}
@@ -42,8 +52,12 @@ void PageFrameAllocator::init(){
uintptr_t end = (uintptr_t)memory_map_entry->getEndAddress();
bool available = memory_map_entry->isAvailable();
if(available)
mark_pageframes(start, end, true);
if(available){
if(start < (uintptr_t)&___KERNEL_END___)
start = Page::ceil((uintptr_t)&___KERNEL_END___ +1);
mark_pageframes(start, end, available);
}
memory_map_entry = memory_map_entry->getNext();
}
@@ -55,8 +69,9 @@ void PageFrameAllocator::init(){
uintptr_t end = (uintptr_t)memory_map_entry->getEndAddress();
bool available = memory_map_entry->isAvailable();
if(!available)
mark_pageframes(start, end, false);
if(!available){
mark_pageframes(start, end, available);
}
memory_map_entry = memory_map_entry->getNext();
}
@@ -113,31 +128,18 @@ void PageFrameAllocator::stats(){
}
void* PageFrameAllocator::alloc(bool kernel){
uintptr_t search_start;
uintptr_t search_end;
if(kernel){
search_start = Page::ceil((uintptr_t)&___KERNEL_END___);
search_end = 0x4000000;
}
else{
search_start = 0x4000000;
search_end = 0x8000000; //TODO find some appropriate value
}
uint64_t free_pageframe=0;
//TODO make this more efficent
for(uint64_t i=search_start/4096; i < search_end/4096; i++){
if(PageFrames[i].available){
free_pageframe = i;
break;
}
}
Queue<PageFrame>* q = kernel?&kernel_memory_q:&user_memory_q;
PageFrame* free_pageframe = q->dequeue();
if(!free_pageframe)
return 0;
mark_pageframes(free_pageframe*4096, (free_pageframe*4096)+1, false);
return (void*)(free_pageframe*4096);
free_pageframe->available = false;
uintptr_t addr = ((free_pageframe - &PageFrames[0]))<<12;
mark_pageframes(addr, addr+1, false);
return (void*)(addr);
}
void PageFrameAllocator::free(PageFrame* frame){