[PATCH v2 03/10] powerpc/mm/slice: pass pointers to struct slice_mask where possible
Nicholas Piggin
npiggin at gmail.com
Wed Mar 7 12:37:11 AEDT 2018
Pass around const pointers to struct slice_mask where possible, rather
than copies of slice_mask, to reduce stack and call overhead.
checkstack.pl gives, before:
0x00000d1c slice_get_unmapped_area [slice.o]: 592
0x00001864 is_hugepage_only_range [slice.o]: 448
0x00000754 slice_find_area_topdown [slice.o]: 400
0x00000484 slice_find_area_bottomup.isra.1 [slice.o]: 272
0x000017b4 slice_set_range_psize [slice.o]: 224
0x00000a4c slice_find_area [slice.o]: 128
0x00000160 slice_check_fit [slice.o]: 112
after:
0x00000ad0 slice_get_unmapped_area [slice.o]: 448
0x00001464 is_hugepage_only_range [slice.o]: 288
0x000006c0 slice_find_area [slice.o]: 144
0x0000016c slice_check_fit [slice.o]: 128
0x00000528 slice_find_area_bottomup.isra.2 [slice.o]: 128
0x000013e4 slice_set_range_psize [slice.o]: 128
This increases vfork+exec+exit performance by 1.5%.
Reduces time to mmap+munmap a 64kB page by 17%.
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
arch/powerpc/mm/slice.c | 84 ++++++++++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 39 deletions(-)
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 432c328b3e94..420d791f0e18 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -50,19 +50,21 @@ struct slice_mask {
#ifdef DEBUG
int _slice_debug = 1;
-static void slice_print_mask(const char *label, struct slice_mask mask)
+static void slice_print_mask(const char *label, const struct slice_mask *mask)
{
if (!_slice_debug)
return;
- pr_devel("%s low_slice: %*pbl\n", label, (int)SLICE_NUM_LOW, &mask.low_slices);
- pr_devel("%s high_slice: %*pbl\n", label, (int)SLICE_NUM_HIGH, mask.high_slices);
+ pr_devel("%s low_slice: %*pbl\n", label,
+ (int)SLICE_NUM_LOW, &mask->low_slices);
+ pr_devel("%s high_slice: %*pbl\n", label,
+ (int)SLICE_NUM_HIGH, mask->high_slices);
}
#define slice_dbg(fmt...) do { if (_slice_debug) pr_devel(fmt); } while (0)
#else
-static void slice_print_mask(const char *label, struct slice_mask mask) {}
+static void slice_print_mask(const char *label, const struct slice_mask *mask) {}
#define slice_dbg(fmt...)
#endif
@@ -179,7 +181,8 @@ static void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_ma
}
static int slice_check_fit(struct mm_struct *mm,
- struct slice_mask mask, struct slice_mask available)
+ const struct slice_mask *mask,
+ const struct slice_mask *available)
{
DECLARE_BITMAP(result, SLICE_NUM_HIGH);
/*
@@ -189,14 +192,14 @@ static int slice_check_fit(struct mm_struct *mm,
unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit);
if (!SLICE_NUM_HIGH)
- return (mask.low_slices & available.low_slices) ==
- mask.low_slices;
+ return (mask->low_slices & available->low_slices) ==
+ mask->low_slices;
- bitmap_and(result, mask.high_slices,
- available.high_slices, slice_count);
+ bitmap_and(result, mask->high_slices,
+ available->high_slices, slice_count);
- return (mask.low_slices & available.low_slices) == mask.low_slices &&
- bitmap_equal(result, mask.high_slices, slice_count);
+ return (mask->low_slices & available->low_slices) == mask->low_slices &&
+ bitmap_equal(result, mask->high_slices, slice_count);
}
static void slice_flush_segments(void *parm)
@@ -216,7 +219,8 @@ static void slice_flush_segments(void *parm)
#endif
}
-static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psize)
+static void slice_convert(struct mm_struct *mm,
+ const struct slice_mask *mask, int psize)
{
int index, mask_index;
/* Write the new slice psize bits */
@@ -233,7 +237,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
lpsizes = mm->context.low_slices_psize;
for (i = 0; i < SLICE_NUM_LOW; i++) {
- if (!(mask.low_slices & (1u << i)))
+ if (!(mask->low_slices & (1u << i)))
continue;
mask_index = i & 0x1;
@@ -244,7 +248,7 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
hpsizes = mm->context.high_slices_psize;
for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) {
- if (!test_bit(i, mask.high_slices))
+ if (!test_bit(i, mask->high_slices))
continue;
mask_index = i & 0x1;
@@ -270,26 +274,25 @@ static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psiz
* 'available' slice_mark.
*/
static bool slice_scan_available(unsigned long addr,
- struct slice_mask available,
- int end,
- unsigned long *boundary_addr)
+ const struct slice_mask *available,
+ int end, unsigned long *boundary_addr)
{
unsigned long slice;
if (addr < SLICE_LOW_TOP) {
slice = GET_LOW_SLICE_INDEX(addr);
*boundary_addr = (slice + end) << SLICE_LOW_SHIFT;
- return !!(available.low_slices & (1u << slice));
+ return !!(available->low_slices & (1u << slice));
} else {
slice = GET_HIGH_SLICE_INDEX(addr);
*boundary_addr = (slice + end) ?
((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;
- return !!test_bit(slice, available.high_slices);
+ return !!test_bit(slice, available->high_slices);
}
}
static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
unsigned long len,
- struct slice_mask available,
+ const struct slice_mask *available,
int psize, unsigned long high_limit)
{
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
@@ -335,7 +338,7 @@ static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
static unsigned long slice_find_area_topdown(struct mm_struct *mm,
unsigned long len,
- struct slice_mask available,
+ const struct slice_mask *available,
int psize, unsigned long high_limit)
{
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
@@ -393,7 +396,7 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
- struct slice_mask mask, int psize,
+ const struct slice_mask *mask, int psize,
int topdown, unsigned long high_limit)
{
if (topdown)
@@ -402,7 +405,8 @@ static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
return slice_find_area_bottomup(mm, len, mask, psize, high_limit);
}
-static inline void slice_or_mask(struct slice_mask *dst, struct slice_mask *src)
+static inline void slice_or_mask(struct slice_mask *dst,
+ const struct slice_mask *src)
{
dst->low_slices |= src->low_slices;
if (!SLICE_NUM_HIGH)
@@ -411,7 +415,8 @@ static inline void slice_or_mask(struct slice_mask *dst, struct slice_mask *src)
SLICE_NUM_HIGH);
}
-static inline void slice_andnot_mask(struct slice_mask *dst, struct slice_mask *src)
+static inline void slice_andnot_mask(struct slice_mask *dst,
+ const struct slice_mask *src)
{
dst->low_slices &= ~src->low_slices;
@@ -501,7 +506,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
* already
*/
slice_mask_for_size(mm, psize, &good_mask, high_limit);
- slice_print_mask(" good_mask", good_mask);
+ slice_print_mask(" good_mask", &good_mask);
/*
* Here "good" means slices that are already the right page size,
@@ -535,12 +540,12 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
if (addr != 0 || fixed) {
/* Build a mask for the requested range */
slice_range_to_mask(addr, len, &mask);
- slice_print_mask(" mask", mask);
+ slice_print_mask(" mask", &mask);
/* Check if we fit in the good mask. If we do, we just return,
* nothing else to do
*/
- if (slice_check_fit(mm, mask, good_mask)) {
+ if (slice_check_fit(mm, &mask, &good_mask)) {
slice_dbg(" fits good !\n");
return addr;
}
@@ -548,7 +553,7 @@ 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
*/
- newaddr = slice_find_area(mm, len, good_mask,
+ newaddr = slice_find_area(mm, len, &good_mask,
psize, topdown, high_limit);
if (newaddr != -ENOMEM) {
/* Found within the good mask, we don't have to setup,
@@ -564,9 +569,10 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
*/
slice_mask_for_free(mm, &potential_mask, high_limit);
slice_or_mask(&potential_mask, &good_mask);
- slice_print_mask(" potential", potential_mask);
+ slice_print_mask(" potential", &potential_mask);
- if ((addr != 0 || fixed) && slice_check_fit(mm, mask, potential_mask)) {
+ if ((addr != 0 || fixed) &&
+ slice_check_fit(mm, &mask, &potential_mask)) {
slice_dbg(" fits potential !\n");
goto convert;
}
@@ -581,7 +587,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
* anywhere in the good area.
*/
if (addr) {
- addr = slice_find_area(mm, len, good_mask,
+ addr = slice_find_area(mm, len, &good_mask,
psize, topdown, high_limit);
if (addr != -ENOMEM) {
slice_dbg(" found area at 0x%lx\n", addr);
@@ -592,14 +598,14 @@ 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, &potential_mask,
psize, topdown, high_limit);
#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, &compat_mask);
- addr = slice_find_area(mm, len, potential_mask,
+ addr = slice_find_area(mm, len, &potential_mask,
psize, topdown, high_limit);
}
#endif
@@ -609,7 +615,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
slice_range_to_mask(addr, len, &mask);
slice_dbg(" found potential area at 0x%lx\n", addr);
- slice_print_mask(" mask", mask);
+ slice_print_mask(" mask", &mask);
convert:
slice_andnot_mask(&mask, &good_mask);
@@ -617,7 +623,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
if (mask.low_slices ||
(SLICE_NUM_HIGH &&
!bitmap_empty(mask.high_slices, SLICE_NUM_HIGH))) {
- slice_convert(mm, mask, psize);
+ slice_convert(mm, &mask, psize);
if (psize > MMU_PAGE_BASE)
on_each_cpu(slice_flush_segments, mm, 1);
}
@@ -711,7 +717,7 @@ void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
VM_BUG_ON(radix_enabled());
slice_range_to_mask(start, len, &mask);
- slice_convert(mm, mask, psize);
+ slice_convert(mm, &mask, psize);
}
#ifdef CONFIG_HUGETLB_PAGE
@@ -758,9 +764,9 @@ int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
#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);
+ slice_print_mask(" mask", &mask);
+ slice_print_mask(" available", &available);
#endif
- return !slice_check_fit(mm, mask, available);
+ return !slice_check_fit(mm, &mask, &available);
}
#endif
--
2.16.1
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