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bh=9iBLBVu4Mhxhwxhe5dNl/Id2BVh8iQhncps+VFZFtKM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=I8MXmpmj957CpcpmfEDfR94xFi/Rh7qubhkjaPEvNOuqShk/+wVABj5q6MTXpjo4s xDpGtThspfjKNIvg2HNiAB8T6Oy4TbPyxhn5cFxcc0pHqK6Ktvf4KO+PJysSk3cLSV c1BnJrP1PxS0lHGdaSDmyecSwu3HZ83MlfrpVrLY= Date: Sun, 12 Mar 2023 14:01:10 -0700 From: Andrew Morton To: Zhenhua Huang Cc: , , , , , , , , , , , , , , Subject: Re: [PATCH v4] mm,kfence: decouple kfence from page granularity mapping judgement Message-Id: <20230312140110.4f3571b92a2556767d7667fc@linux-foundation.org> In-Reply-To: <1678440604-796-1-git-send-email-quic_zhenhuah@quicinc.com> References: <1678440604-796-1-git-send-email-quic_zhenhuah@quicinc.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 81BF6C0022 X-Rspam-User: X-Stat-Signature: fe85n6r1zte7mn9iwrrtru3rs4mt4t3u X-HE-Tag: 1678654874-337986 X-HE-Meta: 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 qXf82Kb0 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 10 Mar 2023 17:30:04 +0800 Zhenhua Huang wrote: > Kfence only needs its pool to be mapped as page granularity, previous > judgement was a bit over protected. Decouple it from judgement and do > page granularity mapping for kfence pool only [1]. > > To implement this, also relocate the kfence pool allocation before the > linear mapping setting up, arm64_kfence_alloc_pool is to allocate phys > addr, __kfence_pool is to be set after linear mapping set up. Why make this change? What are the benefits? What are the user visible effects? > LINK: [1] https://lore.kernel.org/linux-arm-kernel/1675750519-1064-1-git-send-email-quic_zhenhuah@quicinc.com/T/ Chasing the links indicates that "page-granular mapping costed more (2M per 1GB) memory". Please spell all this out in this patch's changelog. btw. this format: Link: https://lore.kernel.org/linux-arm-kernel/1675750519-1064-1-git-send-email-quic_zhenhuah@quicinc.com/T/ [1] is conventional.