From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x241.google.com (mail-pf0-x241.google.com [IPv6:2607:f8b0:400e:c00::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zdvnB3mVlzF0cb for ; Sun, 11 Feb 2018 01:43:25 +1100 (AEDT) Received: by mail-pf0-x241.google.com with SMTP id 17so2419243pfw.11 for ; Sat, 10 Feb 2018 06:43:25 -0800 (PST) Date: Sun, 11 Feb 2018 00:43:09 +1000 From: Nicholas Piggin To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood , aneesh.kumar@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v4 1/5] powerpc/mm/slice: Remove intermediate bitmap copy Message-ID: <20180211004309.2eda56a3@roar.ozlabs.ibm.com> In-Reply-To: <01e8f783db8f4d4d41df91e0400a8634272b326f.1518226173.git.christophe.leroy@c-s.fr> References: <01e8f783db8f4d4d41df91e0400a8634272b326f.1518226173.git.christophe.leroy@c-s.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 10 Feb 2018 13:54:25 +0100 (CET) Christophe Leroy 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 > > Signed-off-by: Christophe Leroy > Reviewed-by: Aneesh Kumar K.V > --- > 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