This patch kill potential_mask and compat_mask variable and instead use tmp_mask
so that we can reduce the stack usage. This is required so that we can increase
the high_slices bitmap to a larger value.
The patch does result in extra computation in final stage, where it ends up
recomputing the compat mask again.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/mm/slice.c | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 259bbda9a222..832c681c341a 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -413,8 +413,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
{
struct slice_mask mask;
struct slice_mask good_mask;
- struct slice_mask potential_mask;
- struct slice_mask compat_mask;
+ struct slice_mask tmp_mask;
int fixed = (flags & MAP_FIXED);
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
unsigned long page_size = 1UL << pshift;
@@ -449,11 +448,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
bitmap_zero(mask.high_slices, SLICE_NUM_HIGH);
/* silence stupid warning */;
- potential_mask.low_slices = 0;
- bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH);
-
- compat_mask.low_slices = 0;
- bitmap_zero(compat_mask.high_slices, SLICE_NUM_HIGH);
+ tmp_mask.low_slices = 0;
+ bitmap_zero(tmp_mask.high_slices, SLICE_NUM_HIGH);
/* Sanity checks */
BUG_ON(mm->task_size == 0);
@@ -502,9 +498,11 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
#ifdef CONFIG_PPC_64K_PAGES
/* If we support combo pages, we can allow 64k pages in 4k slices */
if (psize == MMU_PAGE_64K) {
- slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask, high_limit);
+ slice_mask_for_size(mm, MMU_PAGE_4K, &tmp_mask, high_limit);
if (fixed)
- slice_or_mask(&good_mask, &compat_mask);
+ slice_or_mask(&good_mask, &tmp_mask);
+
+ slice_print_mask("Mask for compat page size", tmp_mask);
}
#endif
/* First check hint if it's valid or if we have MAP_FIXED */
@@ -541,11 +539,11 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
* We don't fit in the good mask, check what other slices are
* empty and thus can be converted
*/
- slice_mask_for_free(mm, &potential_mask, high_limit);
- slice_or_mask(&potential_mask, &good_mask);
- slice_print_mask(" potential", potential_mask);
+ slice_mask_for_free(mm, &tmp_mask, high_limit);
+ slice_or_mask(&tmp_mask, &good_mask);
+ slice_print_mask("Free area/potential ", tmp_mask);
- if ((addr != 0 || fixed) && slice_check_fit(mm, mask, potential_mask)) {
+ if ((addr != 0 || fixed) && slice_check_fit(mm, mask, tmp_mask)) {
slice_dbg(" fits potential !\n");
goto convert;
}
@@ -571,7 +569,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
/* Now let's see if we can find something in the existing slices
* for that size plus free slices
*/
- addr = slice_find_area(mm, len, potential_mask,
+ addr = slice_find_area(mm, len, tmp_mask,
psize, topdown, high_limit);
#ifdef CONFIG_PPC_64K_PAGES
@@ -585,9 +583,10 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
* mask variable is free here. Use that for compat
* size mask.
*/
+ slice_mask_for_size(mm, MMU_PAGE_4K, &mask, high_limit);
/* retry the search with 4k-page slices included */
- slice_or_mask(&potential_mask, &compat_mask);
- addr = slice_find_area(mm, len, potential_mask,
+ slice_or_mask(&tmp_mask, &mask);
+ addr = slice_find_area(mm, len, tmp_mask,
psize, topdown, high_limit);
}
#endif
@@ -600,8 +599,9 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
slice_print_mask(" mask", mask);
convert:
+ slice_mask_for_size(mm, MMU_PAGE_4K, &tmp_mask, high_limit);
slice_andnot_mask(&mask, &good_mask);
- slice_andnot_mask(&mask, &compat_mask);
+ slice_andnot_mask(&mask, &tmp_mask);
if (mask.low_slices || !bitmap_empty(mask.high_slices, SLICE_NUM_HIGH))
{
slice_convert(mm, mask, psize);
if (psize > MMU_PAGE_BASE)
--
2.14.3
