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Message-Id: <6a8c9183257dfcfeb1d8ed1ecc778ec3da19dcd4.1518382747.git.christophe.leroy@c-s.fr>
Date: Mon, 12 Feb 2018 19:12:28 +0100 (CET)
From: Christophe Leroy <christophe.leroy@....fr>
To: Nicholas Piggin <npiggin@...il.com>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [RFC REBASED 4/5] powerpc/mm/slice: Use const pointers to cached slice
masks where possible
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.
This also converts the slice_mask bit operation helpers to be the usual
3-operand kind, which is clearer to work with. And we remove some
unnecessary intermediate bitmaps, reducing stack and copy overhead
further.
Signed-off-by: Nicholas Piggin <npiggin@...il.com>
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
arch/powerpc/include/asm/book3s/64/slice.h | 7 +++
arch/powerpc/include/asm/nohash/32/slice.h | 6 +++
arch/powerpc/mm/slice.c | 77 ++++++++++++++++++------------
3 files changed, 59 insertions(+), 31 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/slice.h b/arch/powerpc/include/asm/book3s/64/slice.h
index f9a2c8bd7a77..be1ce8e91ad1 100644
--- a/arch/powerpc/include/asm/book3s/64/slice.h
+++ b/arch/powerpc/include/asm/book3s/64/slice.h
@@ -63,6 +63,13 @@ static inline void slice_bitmap_set(unsigned long *map, unsigned int start,
{
bitmap_set(map, start, nbits);
}
+
+static inline void slice_bitmap_copy(unsigned long *dst,
+ const unsigned long *src,
+ unsigned int nbits)
+{
+ bitmap_copy(dst, src, nbits);
+}
#endif /* __ASSEMBLY__ */
#else /* CONFIG_PPC_MM_SLICES */
diff --git a/arch/powerpc/include/asm/nohash/32/slice.h b/arch/powerpc/include/asm/nohash/32/slice.h
index bcb4924f7d22..38f041e01a0a 100644
--- a/arch/powerpc/include/asm/nohash/32/slice.h
+++ b/arch/powerpc/include/asm/nohash/32/slice.h
@@ -58,6 +58,12 @@ static inline void slice_bitmap_set(unsigned long *map, unsigned int start,
unsigned int nbits)
{
}
+
+static inline void slice_bitmap_copy(unsigned long *dst,
+ const unsigned long *src,
+ unsigned int nbits)
+{
+}
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_PPC_MM_SLICES */
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 311168ca3939..b8b691369c29 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -468,21 +468,30 @@ 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,
+static inline void slice_copy_mask(struct slice_mask *dst,
const struct slice_mask *src)
{
- dst->low_slices |= src->low_slices;
- slice_bitmap_or(dst->high_slices, dst->high_slices, src->high_slices,
+ dst->low_slices = src->low_slices;
+ slice_bitmap_copy(dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
+}
+
+static inline void slice_or_mask(struct slice_mask *dst,
+ const struct slice_mask *src1,
+ const struct slice_mask *src2)
+{
+ dst->low_slices = src1->low_slices | src2->low_slices;
+ slice_bitmap_or(dst->high_slices, src1->high_slices, src2->high_slices,
SLICE_NUM_HIGH);
}
static inline void slice_andnot_mask(struct slice_mask *dst,
- const struct slice_mask *src)
+ const struct slice_mask *src1,
+ const struct slice_mask *src2)
{
- dst->low_slices &= ~src->low_slices;
+ dst->low_slices = src1->low_slices & ~src2->low_slices;
- slice_bitmap_andnot(dst->high_slices, dst->high_slices,
- src->high_slices, SLICE_NUM_HIGH);
+ slice_bitmap_andnot(dst->high_slices, src1->high_slices,
+ src2->high_slices, SLICE_NUM_HIGH);
}
#ifdef CONFIG_PPC_64K_PAGES
@@ -495,10 +504,10 @@ 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;
@@ -537,9 +546,6 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
potential_mask.low_slices = 0;
slice_bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH);
- compat_mask.low_slices = 0;
- slice_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);
@@ -562,7 +568,7 @@ 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);
+ maskp = slice_mask_for_size(mm, psize);
slice_print_mask(" good_mask", &good_mask);
/*
@@ -587,11 +593,16 @@ 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, &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);
+ }
/* First check hint if it's valid or if we have MAP_FIXED */
if (addr || fixed) {
@@ -621,7 +632,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
* empty and thus can be converted
*/
slice_mask_for_free(mm, &potential_mask, high_limit);
- slice_or_mask(&potential_mask, &good_mask);
+ slice_or_mask(&potential_mask, &potential_mask, &good_mask);
slice_print_mask(" potential", &potential_mask);
if (addr || fixed) {
@@ -658,7 +669,7 @@ 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, &compat_mask);
+ slice_or_mask(&potential_mask, &potential_mask, compat_maskp);
addr = slice_find_area(mm, len, &potential_mask,
psize, topdown, high_limit);
}
@@ -667,16 +678,17 @@ 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", maskp);
convert:
- slice_andnot_mask(&mask, &good_mask);
- slice_andnot_mask(&mask, &compat_mask);
- if (mask.low_slices ||
- !slice_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_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);
}
@@ -834,19 +846,22 @@ 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, &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
@@ -856,6 +871,6 @@ 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_range_fits(mm, &available, addr, len);
+ return !slice_check_range_fits(mm, maskp, addr, len);
}
#endif
--
2.13.3
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