x86: mtrr_cleanup optimization, v2

fix hpa's t61 with 4g ram:

   change layout from
	(n - 1)*chunksize + chunk_size - NC
   to
	n*chunksize - NC

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index cc135572882ad8d22dfa0eef6e77ac22beb21d93..93d575ac61a3366c524b9f10cb142450e0fa7719 100644 (file)
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -970,6 +970,8 @@ range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
        /* try to append some small hole */
        range0_basek = state->range_startk;
        range0_sizek = ALIGN(state->range_sizek, chunk_sizek);
+
+       /* no increase */
        if (range0_sizek == state->range_sizek) {
                if (debug_print)
                        printk(KERN_DEBUG "rangeX: %016lx - %016lx\n",
@@ -980,13 +982,13 @@ range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
                return 0;
        }
 
-       range0_sizek -= chunk_sizek;
-       if (range0_sizek && sizek) {
-           while (range0_basek + range0_sizek > (basek + sizek)) {
-               range0_sizek -= chunk_sizek;
-               if (!range0_sizek)
-                       break;
-           }
+       /* only cut back, when it is not the last */
+       if (sizek) {
+               while (range0_basek + range0_sizek > (basek + sizek)) {
+                       range0_sizek -= chunk_sizek;
+                       if (!range0_sizek)
+                               break;
+               }
        }
 
        if (range0_sizek) {
@@ -1000,46 +1002,39 @@ range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
        }
 
        range_basek = range0_basek + range0_sizek;
-       range_sizek = chunk_sizek;
 
-       if (range_basek + range_sizek > basek &&
-           range_basek + range_sizek <= (basek + sizek)) {
-               /* one hole */
-               second_basek = basek;
-               second_sizek = range_basek + range_sizek - basek;
-       }
+       /* one hole in the middle */
+       if (range_basek > basek && range_basek <= (basek + sizek))
+               second_sizek = range_basek - basek;
 
-       /* if last piece, only could one hole near end */
-       if ((second_basek || !basek) &&
-           range_sizek - (state->range_sizek - range0_sizek) - second_sizek <
-           (chunk_sizek >> 1)) {
-               /*
-                * one hole in middle (second_sizek is 0) or at end
-                * (second_sizek is 0 )
-                */
-               hole_sizek = range_sizek - (state->range_sizek - range0_sizek)
-                                - second_sizek;
-               hole_basek = range_basek + range_sizek - hole_sizek
-                                - second_sizek;
-       } else {
-               /* fallback for big hole, or several holes */
+       if (range0_sizek > state->range_sizek) {
+               unsigned long hole_basek, hole_sizek;
+
+               /* one hole in middle or at end */
+               hole_sizek = range0_sizek - state->range_sizek - second_sizek;
+               if (hole_sizek) {
+                       hole_basek = range_basek - hole_sizek - second_sizek;
+                       if (debug_print)
+                               printk(KERN_DEBUG "hole: %016lx - %016lx\n",
+                                        hole_basek<<10,
+                                        (hole_basek + hole_sizek)<<10);
+                       state->reg = range_to_mtrr(state->reg, hole_basek,
+                                                  hole_sizek,
+                                                  MTRR_TYPE_UNCACHABLE);
+               }
+       } else  {
+               /* need to handle left over */
                range_sizek = state->range_sizek - range0_sizek;
-               second_basek = 0;
-               second_sizek = 0;
-       }
 
-       if (debug_print)
-               printk(KERN_DEBUG "range: %016lx - %016lx\n", range_basek<<10,
-                        (range_basek + range_sizek)<<10);
-       state->reg = range_to_mtrr(state->reg, range_basek, range_sizek,
+               if (range_sizek) {
+                       if (debug_print)
+                               printk(KERN_DEBUG "range: %016lx - %016lx\n",
+                                        range_basek<<10,
+                                        (range_basek + range_sizek)<<10);
+                       state->reg = range_to_mtrr(state->reg, range_basek,
+                                        range_sizek,
                                         MTRR_TYPE_WRBACK);
-       if (hole_sizek) {
-               if (debug_print)
-                       printk(KERN_DEBUG "hole: %016lx - %016lx\n",
-                                hole_basek<<10, (hole_basek + hole_sizek)<<10);
-               state->reg = range_to_mtrr(state->reg, hole_basek, hole_sizek,
-                                                MTRR_TYPE_UNCACHABLE);
-
+               }
        }
 
        return second_sizek;