Expose the number of available physical pages

xtoskrnl/includes/mm/pfn.hh

@@ -45,6 +45,7 @@ namespace MM
                                                   IN PFN_NUMBER PageFrameIndex,
                                                   IN BOOLEAN BeginStandbyList = FALSE);
             STATIC XTAPI VOID FreePhysicalPage(IN PMMPTE PointerPte);
+            STATIC XTAPI PFN_NUMBER GetAvailablePages(VOID);
             STATIC XTAPI ULONG_PTR GetHighestPhysicalPage(VOID);
             STATIC XTAPI ULONGLONG GetNumberOfPhysicalPages(VOID);
             STATIC XTAPI PMMPFN GetPfnEntry(IN PFN_NUMBER Pfn);

xtoskrnl/mm/pfn.cc

@@ -351,6 +351,21 @@ MM::Pfn::FreePhysicalPage(IN PMMPTE PointerPte)
     MM::Pfn::DecrementShareCount(PageFrame, PageFrameNumber, FALSE);
 }
 
+/**
+ * Retrieves the number of available physical pages.
+ *
+ * @return This routine returns the number of available physical pages.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+PFN_NUMBER
+MM::Pfn::GetAvailablePages(VOID)
+{
+    /* Return the number of available pages */
+    return AvailablePages;
+}
+
 /**
  * Retrieves the highest physical page number (PFN) detected in the system.
  *