Re: [PATCH v4 1/5] powerpc/mm/slice: Remove intermediate bitmap copy
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2018-02-10 14:43:25
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On Sat, 10 Feb 2018 13:54:25 +0100 (CET) Christophe Leroy [off-list ref] wrote:
bitmap_or() and bitmap_andnot() can work properly with dst identical to src1 or src2. There is no need of an intermediate result bitmap that is copied back to dst in a second step.
Everyone seems to be working on the slice code all of a sudden. I had the same change in my series I just posted, but I didn't notice this one of yours earlier, and it's better split out, so this is fine by me. Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
quoted hunk ↗ jump to hunk
Signed-off-by: Christophe Leroy <redacted> Reviewed-by: Aneesh Kumar K.V <redacted> --- v2: New in v2 v3: patch moved up front of the serie to avoid ephemeral slice_bitmap_copy() function in following patch v4: No change arch/powerpc/mm/slice.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c index 23ec2c5e3b78..98b53d48968f 100644 --- a/arch/powerpc/mm/slice.c +++ b/arch/powerpc/mm/slice.c@@ -388,21 +388,17 @@ static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len, static inline void slice_or_mask(struct slice_mask *dst, struct slice_mask *src) { - DECLARE_BITMAP(result, SLICE_NUM_HIGH); - dst->low_slices |= src->low_slices; - bitmap_or(result, dst->high_slices, src->high_slices, SLICE_NUM_HIGH); - bitmap_copy(dst->high_slices, result, SLICE_NUM_HIGH); + bitmap_or(dst->high_slices, dst->high_slices, src->high_slices, + SLICE_NUM_HIGH); } static inline void slice_andnot_mask(struct slice_mask *dst, struct slice_mask *src) { - DECLARE_BITMAP(result, SLICE_NUM_HIGH); - dst->low_slices &= ~src->low_slices; - bitmap_andnot(result, dst->high_slices, src->high_slices, SLICE_NUM_HIGH); - bitmap_copy(dst->high_slices, result, SLICE_NUM_HIGH); + bitmap_andnot(dst->high_slices, dst->high_slices, src->high_slices, + SLICE_NUM_HIGH); } #ifdef CONFIG_PPC_64K_PAGES