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- Implement several changes to PFN database management:
- The PTEs for the PFN Database are now created by ARM3. Unlike the old code which create PTE for every page on the machine, ARM3 only creates PTEs to account for pages that should be in the PFN database.
- A second related change is what "pages should be in the PFN database". Previously, reserved or otherwise non-existing (ie: holes) memory regions would get a PFN entry created and marked as "BIOS". This is wasteful and not compatible with Windows: there should not be PFN entries created at all.
- So we removed BIOS PFN entries, and now only create PTEs for valid pages as listed in the physical memory ranges.
- This allows machines with "holes" in their physical address space not to waste dozens of MBs of nonpaged pool
- Also saves memory on regular machines too, since 1-4MB worth of memory will now not be in the DB anymore
- To keep track of pages that are invalid/unknown/ignored, there is now a "PFN Bitmap". This bitmap has one bit set for each valid PFN in the database.
- And so, MiGetPfnEntry now also validates that, if there is a PFN Bitmap, the requested PFN is actually present in the database.
- This introduces a major functional change: device pages, reserved pages, and other BIOS pages cannot be referenced, shared, or managed in any meaningful way.
- We have attempted to fix parts of the OS that depended on this, but there may still be bugs.
- A known issue may be an assertion during reboot and/or shutdown in the hyperspace mapping function. It is currently safe to simply "cont" in the debugger a couple of times.
- We are working on a fix.
svn path=/trunk/; revision=42220
======================== ReactOS Version 0.3.x Updated Dec 16, 2006 ======================== 1. What is ReactOS? ReactOS is an Open Source effort to develop a quality operating system that is compatible with Windows NT applications and drivers. The ReactOS project, although currently focused on Windows XP/2003 drivers compatibility, is always keeping an eye toward compatibility with older version of Windows NT family ( NT 4.0, 2000 (NT 5.0)) and new Windows NT releases (Vista, etc). Applications (Win32 API) compatibility focus is Windows XP. More information is available at http://www.reactos.org/. 2. Building ReactOS See the INSTALL file for more details. 3. More information See the media\doc subdirectory for some sparse notes. 4. Who is responsible See the CREDITS file.