powerpc/mm: Add addr_limit to mm_context and use it to derive max slice index

In the followup patch, we will increase the slice array size to handle
512TB range, but will limit the max addr to 128TB. Avoid doing
unnecessary computation and avoid doing slice mask related operation
above address limit.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 11 insertions, 9 deletions

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 95e5a20b1b6a..ded96edac817 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -136,7 +136,7 @@ static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret)
         if (mm->task_size <= SLICE_LOW_TOP)
                 return;
 
-        for (i = 0; i < SLICE_NUM_HIGH; i++)
+        for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++)
                 if (!slice_high_has_vma(mm, i))
                         __set_bit(i, ret->high_slices);
 }
@@ -157,7 +157,7 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
                         ret->low_slices |= 1u << i;
 
         hpsizes = mm->context.high_slices_psize;
-        for (i = 0; i < SLICE_NUM_HIGH; i++) {
+        for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++) {
                 mask_index = i & 0x1;
                 index = i >> 1;
                 if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
@@ -165,15 +165,17 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
         }
 }
 
-static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
+static int slice_check_fit(struct mm_struct *mm,
+                           struct slice_mask mask, struct slice_mask available)
 {
         DECLARE_BITMAP(result, SLICE_NUM_HIGH);
+        unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.addr_limit);
 
         bitmap_and(result, mask.high_slices,
-                   available.high_slices, SLICE_NUM_HIGH);
+                   available.high_slices, slice_count);
 
         return (mask.low_slices & available.low_slices) == mask.low_slices &&
-                bitmap_equal(result, mask.high_slices, SLICE_NUM_HIGH);
+                bitmap_equal(result, mask.high_slices, slice_count);
 }
 
 static void slice_flush_segments(void *parm)
@@ -217,7 +219,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
         mm->context.low_slices_psize = lpsizes;
 
         hpsizes = mm->context.high_slices_psize;
-        for (i = 0; i < SLICE_NUM_HIGH; i++) {
+        for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.addr_limit); i++) {
                 mask_index = i & 0x1;
                 index = i >> 1;
                 if (test_bit(i, mask.high_slices))
@@ -484,7 +486,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
                 /* Check if we fit in the good mask. If we do, we just return,
                  * nothing else to do
                  */
-                if (slice_check_fit(mask, good_mask)) {
+                if (slice_check_fit(mm, mask, good_mask)) {
                         slice_dbg(" fits good !\n");
                         return addr;
                 }
@@ -509,7 +511,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
         slice_or_mask(&potential_mask, &good_mask);
         slice_print_mask(" potential", potential_mask);
 
-        if ((addr != 0 || fixed) && slice_check_fit(mask, potential_mask)) {
+        if ((addr != 0 || fixed) && slice_check_fit(mm, mask, potential_mask)) {
                 slice_dbg(" fits potential !\n");
                 goto convert;
         }
@@ -734,6 +736,6 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
         slice_print_mask(" mask", mask);
         slice_print_mask(" available", available);
 #endif
-        return !slice_check_fit(mask, available);
+        return !slice_check_fit(mm, mask, available);
 }
 #endif