private KernelResult AllocatePagesImpl(out KPageList pageList, ulong pagesCount, bool random)
{
pageList = new KPageList();
int heapIndex = KPageHeap.GetBlockIndex(pagesCount);
if (heapIndex < 0)
{
return(KernelResult.OutOfMemory);
}
for (int index = heapIndex; index >= 0; index--)
{
ulong pagesPerAlloc = KPageHeap.GetBlockPagesCount(index);
while (pagesCount >= pagesPerAlloc)
{
ulong allocatedBlock = _pageHeap.AllocateBlock(index, random);
if (allocatedBlock == 0)
{
break;
}
KernelResult result = pageList.AddRange(allocatedBlock, pagesPerAlloc);
if (result != KernelResult.Success)
{
FreePages(pageList);
_pageHeap.Free(allocatedBlock, pagesPerAlloc);
return(result);
}
pagesCount -= pagesPerAlloc;
}
}
if (pagesCount != 0)
{
FreePages(pageList);
return(KernelResult.OutOfMemory);
}
return(KernelResult.Success);
}
private ulong AllocatePagesContiguousImpl(ulong pagesCount, ulong alignPages, bool random)
{
int heapIndex = KPageHeap.GetAlignedBlockIndex(pagesCount, alignPages);
ulong allocatedBlock = _pageHeap.AllocateBlock(heapIndex, random);
if (allocatedBlock == 0)
{
return(0);
}
ulong allocatedPages = KPageHeap.GetBlockPagesCount(heapIndex);
if (allocatedPages > pagesCount)
{
_pageHeap.Free(allocatedBlock + pagesCount * KPageTableBase.PageSize, allocatedPages - pagesCount);
}
return(allocatedBlock);
}