Changed to a classfull sequential allocation algo

- Means that addresses end up being allocated sequentially (instead
  of in reverse), cleans up the memory dumps.

diff --git a/Kernel/arch/x86/mm_phys.c b/Kernel/arch/x86/mm_phys.c
index faef2b3..4dbb2c3 100644 (file)
--- a/Kernel/arch/x86/mm_phys.c
+++ b/Kernel/arch/x86/mm_phys.c
@@ -131,16 +131,64 @@ void MM_Install(tMBoot_Info *MBoot)
 tPAddr MM_AllocPhys(void)
 {
        // int  a, b, c;
-        int    indx;
+        int    indx = -1;
        tPAddr  ret;
        
        ENTER("");
        
        Mutex_Acquire( &glPhysAlloc );
        
+       // Classful scan
+       #if 1
+       {
+       const int addrClasses[] = {0,16,20,24,32,64};
+       const int numAddrClasses = sizeof(addrClasses)/sizeof(addrClasses[0]);
+        int    i;
+        int    first, last;
+       for( i = numAddrClasses; i -- > 1; )
+       {
+//             Log("Scanning %i (%i bits)", i, addrClasses[i]);
+               first = 1 << (addrClasses[i-1] - 12);
+               last = (1 << (addrClasses[i] - 12)) - 1;
+               // Range is above the last free page
+               if( first > giLastPossibleFree )
+                       continue;
+               // Last possible free page is in the range
+               if( last > giLastPossibleFree )
+                       last = giLastPossibleFree;
+                       
+//             Log(" first=%i,max=%i", first, last);
+               // Scan the range
+               for( indx = first; indx < last; )
+               {
+//                     Log("indx = %i (< %i?)", indx, last);
+                       if( gaSuperBitmap[indx>>10] == -1 ) {
+                               indx += 1024;
+                               continue;
+                       }
+                       
+                       if( gaPageBitmap[indx>>5] == -1 ) {
+                               indx += 32;
+                               continue;
+                       }
+                       
+                       if( gaPageBitmap[indx>>5] & (1 << (indx&31)) ) {
+                               indx ++;
+                               continue;
+                       }
+                       break;
+               }
+               if( indx < last )       break;
+               
+               giLastPossibleFree = first;     // Well, we couldn't find any in this range
+       }
+       // Out of memory?
+       if( i <= 1 )    indx = -1;
+//     Log("indx = %i", indx);
+       }
+       #elif 0
        // Find free page
        // Scan downwards
-       #if 1
        LOG("giLastPossibleFree = %i", giLastPossibleFree);
        for( indx = giLastPossibleFree; indx >= 0; )
        {
@@ -160,6 +208,8 @@ tPAddr MM_AllocPhys(void)
                }
                break;
        }
+       if( indx >= 0 )
+               giLastPossibleFree = indx;
        LOG("indx = %i", indx);
        #else
        c = giLastPossibleFree % 32;
@@ -179,6 +229,8 @@ tPAddr MM_AllocPhys(void)
        for( ; gaPageBitmap[a*32+b] & (1<<c); c-- );
        LOG("a=%i,b=%i,c=%i", a, b, c);
        indx = (a << 10) | (b << 5) | c;
+       if( indx >= 0 )
+               giLastPossibleFree = indx;
        #endif
        
        if( indx < 0 ) {
@@ -203,11 +255,11 @@ tPAddr MM_AllocPhys(void)
        
        // Get address
        ret = indx << 12;
-       giLastPossibleFree = indx;
        
        // Mark used block
-       if(gaPageBitmap[ indx>>5 ] == -1)
+       if(gaPageBitmap[ indx>>5 ] == -1) {
                gaSuperBitmap[indx>>10] |= 1 << ((indx>>5)&31);
+       }
 
        // Release Spinlock
        Mutex_Release( &glPhysAlloc );