Index: Kernel/Core/PageAllocator.cs
===================================================================
--- Kernel/Core/PageAllocator.cs (revision 457)
+++ Kernel/Core/PageAllocator.cs (working copy)
@@ -9,6 +9,7 @@
using SharpOS.AOT;
using SharpOS.ADC;
+using System.Runtime.InteropServices;
namespace SharpOS.Memory {
@@ -25,12 +26,14 @@
static byte *kernelStartPage; // physical pointer to the
first page occupied by the kernel
static uint kernelSize; // kernel image size (pages)
static uint totalPages; // amount of pages with RAM
-
- static uint *fpStack; // stack containing free page
addresses
+
+ static uint currentPage;
+ static uint *fpStack; // stack containing free page addresses
static uint fpStackSize; // size of the free page stack
(KB)
static uint fpStackPointer;
-
- static uint *rpStack; // stack containing reserved
page addresses
+
+ static bool reservedPagesLeft;
+ static ReservedPages *rpStack; // stack containing reserved
page addresses
static uint rpStackSize; // size of the reserved page
stack (KB)
static uint rpStackPointer;
@@ -39,7 +42,13 @@
#endregion
#region Nested types
-
+ [StructLayout(LayoutKind.Sequential)]
+ private struct ReservedPages
+ {
+ public uint Address;
+ public uint Size;
+ }
+
public enum Errors: uint {
Success = 0,
Unknown,
@@ -95,9 +104,10 @@
start += fpStackSize * Pager.AtomicPageSize;
// Allocate the reserved page stack
- rpStack = (uint*)start;
+ rpStack = (ReservedPages*)start;
rpStackPointer = 0;
rpStackSize = 1;
+ reservedPagesLeft = false;
// Allocate paging information
pagingMemory->Start = (byte*)PtrToPage(start +
(rpStackSize * 1024) + (Pager.AtomicPageSize - 1));
@@ -130,13 +140,7 @@
Kernel.Warning("Paging not set in
commandline!");
// NOTE: 0x0000 page is reserved
- for (int i = (int)(totalPages - 1); i >= 1; --i)
- {
- // we should be doing this but it's so slow!
- // it needs to be rewritten to be fast enough
to do..
- //if (!IsPageReserved(page))
- PushFreePage((byte*)(i *
Pager.AtomicPageSize));
- }
+ currentPage = 1;
if (paging)
{
@@ -196,17 +200,21 @@
/// </summary>
public static bool IsPageReserved (void *page)
{
- uint sp = 0;
- uint *ptr = rpStack;
-
- while (sp < rpStackPointer) {
- if (*ptr == (uint)page)
- return true;
- ++sp;
- ++ptr;
- }
-
- return false;
+ uint sp = 0;
+ ReservedPages* ptr = rpStack;
+ uint pageAddr = (uint)page;
+
+ while (sp < rpStackPointer)
+ {
+ if (pageAddr >= ptr->Address && pageAddr <= (ptr->Address +
(ptr->Size * Pager.AtomicPageSize)))
+ {
+ return true;
+ }
+ ++sp;
+ ++ptr;
+ }
+
+ return false;
}
#endregion
@@ -219,16 +227,7 @@
{
void *page = null;
- if (fpStackPointer == 0)
- return null;
-
- do {
- page = PopFreePage ();
- if (!IsPageReserved(page)) // slow!
- return page;
- } while (page != null);
-
- return null;
+ return PopFreePage ();
}
/// <summary>
@@ -432,7 +431,11 @@
#endregion
#region ReservePage () family
-
+ private static ReservedPages* GetReservedPage()
+ {
+ return &rpStack[rpStackPointer++];
+ }
+
/// <summary>
/// Reserves a memory page so that it cannot be allocated using
/// <see cref="M:Alloc()" /> or <see cref="M:RangeAlloc(uint
count)" />.
@@ -442,6 +445,7 @@
/// </param>
public static bool ReservePage(void *page)
{
+ reservedPagesLeft = true;
if (page == null)
return false;
@@ -451,10 +455,12 @@
//if (!IsPageFree(page, &fsp))
// return false;
-
- PushReservedPage(page);
-
- return true;
+
+ ReservedPages* pages = GetReservedPage();
+ pages->Address = (uint)page;
+ pages->Size = 1;
+
+ return true;
}
/// <summary>
@@ -469,13 +475,13 @@
/// </param>
public static bool ReservePageRange(void *firstPage, uint
pages, string name)
{
- byte* page = (byte*)firstPage;
- for (int i = 0; i < pages; i++)
- {
- PushReservedPage(page);
- page += Pager.AtomicPageSize;
- }
- return false;
+ reservedPagesLeft = true;
+
+ ReservedPages* reservePages = GetReservedPage();
+ reservePages->Address = (uint)firstPage;
+ reservePages->Size = pages;
+
+ return true;
}
#endregion
@@ -551,20 +557,31 @@
private static void *PopFreePage()
{
- if (fpStackPointer == 0)
- return null;
- return (void*)fpStack[--fpStackPointer];
+ if (fpStackPointer == 0 && currentPage < (totalPages - 1))
+ {
+ while (currentPage < (totalPages - 1))
+ {
+ uint* page = (uint*)(currentPage * Pager.AtomicPageSize);
+ currentPage++;
+
+ if (IsPageReserved(page))
+ {
+ continue;
+ }
+
+ return (void*)page;
+ }
+ }
+ else if (fpStackPointer == 0)
+ return null;
+
+ return (void*)fpStack[--fpStackPointer];
}
-
- private static void PushReservedPage(void *page)
- {
- rpStack[rpStackPointer++] = (uint)page;
- }
#endregion
#region Debug
- public static void Dump(uint* stack, uint stackptr, int count)
+ public static void DumpStack(uint* stack, uint stackptr,
int count)
{
for (int i = (int)stackptr - 1; i >= 0 && i>= stackptr
- count; i--)
{
@@ -575,12 +592,26 @@
}
}
- public static void Dump(int count)
+ private static void DumpReservedStack(ReservedPages* pageStack, uint
stackPtr, int count)
+ {
+ for (int i = (int)stackPtr - 1; i >= 0 && i >=stackPtr - count;i--)
+ {
+ ADC.TextMode.Write(i);
+ ADC.TextMode.Write(": Address: ");
+ ADC.TextMode.Write((int)pageStack->Address);
+ ADC.TextMode.Write(", Size: ");
+ ADC.TextMode.Write((int)pageStack->Size);
+ pageStack++;
+ ADC.TextMode.WriteLine();
+ }
+ }
+
+ public static void Dump(int count)
{
ADC.TextMode.WriteLine("Free");
- Dump(fpStack, fpStackPointer, count);
+ DumpStack(fpStack, fpStackPointer, count);
ADC.TextMode.WriteLine("Reserved");
- Dump(rpStack, rpStackPointer, count);
+ DumpReservedStack(rpStack, rpStackPointer, count);
}
#endregion
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