Optimize to preallocate big bigs to avoid latter allocations.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2131 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 19 insertions, 10 deletions

diff --git a/EdkModulePkg/Core/DxeIplPeim/Ia32/VirtualMemory.c b/EdkModulePkg/Core/DxeIplPeim/Ia32/VirtualMemory.c
index 78134564e5..609fea2eca 100644
--- a/EdkModulePkg/Core/DxeIplPeim/Ia32/VirtualMemory.c
+++ b/EdkModulePkg/Core/DxeIplPeim/Ia32/VirtualMemory.c
@@ -69,12 +69,8 @@ Returns:
   PAGE_MAP_AND_DIRECTORY_POINTER                *PageMap;

   PAGE_MAP_AND_DIRECTORY_POINTER                *PageDirectoryPointerEntry;

   PAGE_TABLE_ENTRY                              *PageDirectoryEntry;

-

-  //

-  // By architecture only one PageMapLevel4 exists - so lets allocate storage for it.

-  //

-  PageMap = AllocatePages (1);

-  ASSERT (PageMap != NULL);

+  UINTN                                         TotalPagesNum;

+  UINTN                                         BigPageAddress;

 

   //

   // Get physical address bits supported.

@@ -98,6 +94,19 @@ Returns:
     NumberOfPdpEntriesNeeded = 512;

   }

 

+  //

+  // Pre-allocate big pages to avoid later allocations. 

+  //

+  TotalPagesNum = (NumberOfPdpEntriesNeeded + 1) * NumberOfPml4EntriesNeeded + 1;

+  BigPageAddress = (UINTN) AllocatePages (TotalPagesNum);

+  ASSERT (BigPageAddress != 0);

+

+  //

+  // By architecture only one PageMapLevel4 exists - so lets allocate storage for it.

+  //

+  PageMap         = (VOID *) BigPageAddress;

+  BigPageAddress += EFI_PAGE_SIZE;

+

   PageMapLevel4Entry = PageMap;

   PageAddress        = 0;

   for (IndexOfPml4Entries = 0; IndexOfPml4Entries < NumberOfPml4EntriesNeeded; IndexOfPml4Entries++, PageMapLevel4Entry++) {

@@ -105,8 +114,8 @@ Returns:
     // Each PML4 entry points to a page of Page Directory Pointer entires.

     // So lets allocate space for them and fill them in in the IndexOfPdpEntries loop.

     //

-    PageDirectoryPointerEntry = AllocatePages (1);

-    ASSERT (PageDirectoryPointerEntry != NULL);

+    PageDirectoryPointerEntry = (VOID *) BigPageAddress;

+    BigPageAddress += EFI_PAGE_SIZE;

 

     //

     // Make a PML4 Entry

@@ -120,8 +129,8 @@ Returns:
       // Each Directory Pointer entries points to a page of Page Directory entires.

       // So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop.

       //       

-      PageDirectoryEntry = AllocatePages (1);

-      ASSERT (PageDirectoryEntry != NULL);

+      PageDirectoryEntry = (VOID *) BigPageAddress;

+      BigPageAddress += EFI_PAGE_SIZE;

 

       //

       // Fill in a Page Directory Pointer Entries