From fae9aa5c48785389f53dc004bb9188a30faddda9 Mon Sep 17 00:00:00 2001
From: Aleksey Bragin <aleksey@reactos.org>
Date: Sun, 24 Feb 2008 10:43:56 +0000
Subject: [PATCH] - Save original value of the free descriptor we're using to
 alloc early pages from. - Fix handling of PFN database pages inside PFN:
 largest free descriptor does not always end with the highest usable physical
 page (MmPageArraySize). This removes the need for a "good hack" introduced in
 revision 32405. As a result, the memory above the largest free descriptor (if
 it exists) is now correctly marked in the PFN database as free and added to
 the unzeroed list.

svn path=/trunk/; revision=32463
---
 reactos/ntoskrnl/include/internal/mm.h |  1 +
 reactos/ntoskrnl/mm/freelist.c         | 22 ++++++++--------------
 reactos/ntoskrnl/mm/mminit.c           |  5 +++++
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/reactos/ntoskrnl/include/internal/mm.h b/reactos/ntoskrnl/include/internal/mm.h
index b034db263f3..b897fb77d30 100644
--- a/reactos/ntoskrnl/include/internal/mm.h
+++ b/reactos/ntoskrnl/include/internal/mm.h
@@ -19,6 +19,7 @@ extern PVOID MmPagedPoolBase;
 extern ULONG MmPagedPoolSize;
 
 extern PMEMORY_ALLOCATION_DESCRIPTOR MiFreeDescriptor;
+extern MEMORY_ALLOCATION_DESCRIPTOR MiFreeDescriptorOrg;
 extern ULONG MmHighestPhysicalPage;
 extern PVOID MmPfnDatabase;
 
diff --git a/reactos/ntoskrnl/mm/freelist.c b/reactos/ntoskrnl/mm/freelist.c
index bcedb80fc5c..207031b7c87 100644
--- a/reactos/ntoskrnl/mm/freelist.c
+++ b/reactos/ntoskrnl/mm/freelist.c
@@ -54,13 +54,13 @@ MiGetPfnEntry(IN PFN_TYPE Pfn)
 
     /* Make sure the PFN number is valid */
     ASSERT(Pfn <= MmPageArraySize);
-    
+
     /* Get the entry */
     Page = &MmPageArray[Pfn];
-    
+
     /* Make sure it's valid */
     ASSERT_PFN(Page);
-    
+
     /* Return it */
     return Page;
 }
@@ -368,20 +368,14 @@ MmInitializePageList(VOID)
             }
         }
     }
-    
+
     /* Finally handle the pages describing the PFN database themselves */
     for (i = (MiFreeDescriptor->BasePage + MiFreeDescriptor->PageCount);
-         i <= MmPageArraySize;
+         i < (MiFreeDescriptorOrg.BasePage + MiFreeDescriptorOrg.PageCount);
          i++)
     {
-        /* If this page was marked as free it should be removed from
-           the unzeroed free pages list */
-        if (MmPageArray[i].Flags.Type == MM_PHYSICAL_PAGE_FREE)
-        {
-            RemoveEntryList(&MmPageArray[i].ListEntry);
-            UnzeroedPageCount--;
-            MmStats.NrFreePages--;
-        }
+        /* Ensure this page was not added previously */
+        ASSERT(MmPageArray[i].Flags.Type == 0);
 
         /* Mark it as used kernel memory */
         MmPageArray[i] = UsedPage;
@@ -764,7 +758,7 @@ MmAllocPage(ULONG Consumer, SWAPENTRY SavedSwapEntry)
              MiZeroPage(PfnOffset);
              return PfnOffset;
          }
-          
+
          DPRINT1("MmAllocPage(): Out of memory\n");
          KeReleaseSpinLock(&PageListLock, oldIrql);
          return 0;
diff --git a/reactos/ntoskrnl/mm/mminit.c b/reactos/ntoskrnl/mm/mminit.c
index 92898d9e7ae..7578d0d5645 100644
--- a/reactos/ntoskrnl/mm/mminit.c
+++ b/reactos/ntoskrnl/mm/mminit.c
@@ -55,6 +55,7 @@ ULONG_PTR MiKSeg0Start, MiKSeg0End;
 PVOID MmPfnDatabase;
 ULONG_PTR MmPfnDatabaseEnd;
 PMEMORY_ALLOCATION_DESCRIPTOR MiFreeDescriptor;
+MEMORY_ALLOCATION_DESCRIPTOR MiFreeDescriptorOrg;
 extern KMUTANT MmSystemLoadLock;
 BOOLEAN MiDbgEnableMdDump =
 #ifdef _ARM_
@@ -246,6 +247,10 @@ MiCountFreePagesInLoaderBlock(PLOADER_PARAMETER_BLOCK LoaderBlock)
             }
         }
     }
+
+    /* Save original values of the free descriptor, since it'll be
+       altered by early allocations */
+    MiFreeDescriptorOrg = *MiFreeDescriptor;
 }
 
 VOID