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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: AD88420028 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: kzmrcwb97ewqxzhezq1gitqbq4wthdza X-HE-Tag: 1702994840-278084 X-HE-Meta: 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 5GHd7zEn lDknU1GgweVCEYDcJd/X/atYjWigCnAmHGYIh9PV0WRgh+5SvA+e5vbBJslrkihHkQj7iwq09juz3ZkyQUYjR/sG/+nDbjryUXT+LK1p0LghQ60ZBsH+K4oAaBX2MUXMS8DENSGiUc7SxAyF56USSWSdG1g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.001754, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12/19/23 9:01 PM, Matthew Wilcox wrote: > On Tue, Dec 19, 2023 at 01:58:21PM +0800, Jingbo Xu wrote: >> On 12/19/23 12:06 PM, Matthew Wilcox wrote: >>> On Tue, Dec 19, 2023 at 10:42:46AM +0800, Jingbo Xu wrote: >>>> } else { >>>> bdi->max_ratio = max_ratio; >>>> - bdi->max_prop_frac = (FPROP_FRAC_BASE * max_ratio) / 100; >>>> + bdi->max_prop_frac = div64_u64(FPROP_FRAC_BASE * max_ratio, >>>> + 100 * BDI_RATIO_SCALE); >>>> } >>> >>> Why use div64_u64 here? >>> >>> FPROP_FRAC_BASE is an unsigned long. max_ratio is an unsigned int, so >>> the numerator is an unsigned long. BDI_RATIO_SCALE is 10,000, so the >>> numerator is an unsigned int. There's no 64-bit arithmetic needed here. >> >> Yes, div64_u64() is actually not needed here. So it seems >> >> bdi->max_prop_frac = FPROP_FRAC_BASE * max_ratio / 100 / BDI_RATIO_SCALE; >> >> is adequate? > > I'd rather spell that as: > > bdi->max_prop_frac = (FPROP_FRAC_BASE * max_ratio) / > (100 * BDI_RATIO_SCALE); > > It's closer to how you'd write it out mathematically and so it reads > more easily. At least for me. Thanks, I would send v3 soon. -- Thanks, Jingbo