The slice_mask cache was a basic conversion which copied the slice
mask into caller's structures, because that's how the original code
worked. In most cases the pointer can be used directly instead, saving
a copy and an on-stack structure.
On POWER8, this increases vfork+exec+exit performance by 0.3%
and reduces time to mmap+munmap a 64kB page by 2%.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/mm/slice.c | 77 +++++++++++++++++++++----------------------------
1 file changed, 33 insertions(+), 44 deletions(-)
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 46daa1d1794f..086c31b8b982 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -472,10 +472,10 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
unsigned long flags, unsigned int psize,
int topdown)
{
- struct slice_mask mask;
struct slice_mask good_mask;
struct slice_mask potential_mask;
- struct slice_mask compat_mask;
+ const struct slice_mask *maskp;
+ const struct slice_mask *compat_maskp = NULL;
int fixed = (flags & MAP_FIXED);
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
unsigned long page_size = 1UL << pshift;
@@ -509,22 +509,6 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
on_each_cpu(slice_flush_segments, mm, 1);
}
- /*
- * init different masks
- */
- mask.low_slices = 0;
-
- /* silence stupid warning */;
- potential_mask.low_slices = 0;
-
- compat_mask.low_slices = 0;
-
- if (SLICE_NUM_HIGH) {
- bitmap_zero(mask.high_slices, SLICE_NUM_HIGH);
- bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH);
- bitmap_zero(compat_mask.high_slices, SLICE_NUM_HIGH);
- }
-
/* Sanity checks */
BUG_ON(mm->task_size == 0);
BUG_ON(mm->context.slb_addr_limit == 0);
@@ -547,8 +531,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
/* First make up a "good" mask of slices that have the right size
* already
*/
- good_mask = *slice_mask_for_size(mm, psize);
- slice_print_mask(" good_mask", &good_mask);
+ maskp = slice_mask_for_size(mm, psize);
/*
* Here "good" means slices that are already the right page size,
@@ -572,11 +555,19 @@ 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) {
- compat_mask = *slice_mask_for_size(mm, MMU_PAGE_4K);
+ compat_maskp = slice_mask_for_size(mm, MMU_PAGE_4K);
if (fixed)
- slice_or_mask(&good_mask, &good_mask, &compat_mask);
- }
+ slice_or_mask(&good_mask, maskp, compat_maskp);
+ else
+ slice_copy_mask(&good_mask, maskp);
+ } else
#endif
+ {
+ slice_copy_mask(&good_mask, maskp);
+ }
+ slice_print_mask(" good_mask", &good_mask);
+ if (compat_maskp)
+ slice_print_mask(" compat_mask", compat_maskp);
/* First check hint if it's valid or if we have MAP_FIXED */
if (addr || fixed) {
@@ -643,7 +634,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
#ifdef CONFIG_PPC_64K_PAGES
if (addr == -ENOMEM && psize == MMU_PAGE_64K) {
/* retry the search with 4k-page slices included */
- slice_or_mask(&potential_mask, &potential_mask, &compat_mask);
+ slice_or_mask(&potential_mask, &potential_mask, compat_maskp);
addr = slice_find_area(mm, len, &potential_mask,
psize, topdown, high_limit);
}
@@ -652,17 +643,18 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
if (addr == -ENOMEM)
return -ENOMEM;
- slice_range_to_mask(addr, len, &mask);
+ slice_range_to_mask(addr, len, &potential_mask);
slice_dbg(" found potential area at 0x%lx\n", addr);
- slice_print_mask(" mask", &mask);
+ slice_print_mask(" mask", &potential_mask);
convert:
- slice_andnot_mask(&mask, &mask, &good_mask);
- slice_andnot_mask(&mask, &mask, &compat_mask);
- if (mask.low_slices ||
- (SLICE_NUM_HIGH &&
- !bitmap_empty(mask.high_slices, SLICE_NUM_HIGH))) {
- slice_convert(mm, &mask, psize);
+ slice_andnot_mask(&potential_mask, &potential_mask, &good_mask);
+ if (compat_maskp && !fixed)
+ slice_andnot_mask(&potential_mask, &potential_mask,
compat_maskp);
+ if (potential_mask.low_slices ||
+ (SLICE_NUM_HIGH &&
+ !bitmap_empty(potential_mask.high_slices, SLICE_NUM_HIGH))) {
+ slice_convert(mm, &potential_mask, psize);
if (psize > MMU_PAGE_BASE)
on_each_cpu(slice_flush_segments, mm, 1);
}
@@ -786,28 +778,25 @@ void slice_set_range_psize(struct mm_struct *mm, unsigned
long start,
int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
unsigned long len)
{
- struct slice_mask available;
+ const struct slice_mask *maskp;
unsigned int psize = mm->context.user_psize;
if (radix_enabled())
return 0;
- available = *slice_mask_for_size(mm, psize);
+ maskp = slice_mask_for_size(mm, psize);
#ifdef CONFIG_PPC_64K_PAGES
/* We need to account for 4k slices too */
if (psize == MMU_PAGE_64K) {
- struct slice_mask compat_mask;
- compat_mask = *slice_mask_for_size(mm, MMU_PAGE_4K);
- slice_or_mask(&available, &available, &compat_mask);
+ const struct slice_mask *compat_maskp;
+ struct slice_mask available;
+
+ compat_maskp = slice_mask_for_size(mm, MMU_PAGE_4K);
+ slice_or_mask(&available, maskp, compat_maskp);
+ return !slice_check_range_fits(mm, &available, addr, len);
}
#endif
-#if 0 /* too verbose */
- slice_dbg("is_hugepage_only_range(mm=%p, addr=%lx, len=%lx)\n",
- mm, addr, len);
- slice_print_mask(" mask", &mask);
- slice_print_mask(" available", &available);
-#endif
- return !slice_check_range_fits(mm, &available, addr, len);
+ return !slice_check_range_fits(mm, maskp, addr, len);
}
#endif
--
2.16.1
