From 830fd2d45aa11631325404904d02c7b530d40119 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 7 Mar 2018 11:37:11 +1000 Subject: [PATCH] powerpc/mm/slice: pass pointers to struct slice_mask where possible 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 Signed-off-by: Michael Ellerman --- 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 -- 2.30.2