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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1742789988; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FpTdHSPwEvsmWZsMfi/H0HyWwf1LgIbYpVQaMZ5mFv0=; b=UJi45tVYWhTXTE7zTLvkG2mYFehcrZpl6yAA7RL/+bKck3kwxBjPIUBbsZII5Cx/nO5FH4 f55jmCRkdFGF1AObjV2dMwtr4r2XxUr96c9TtetWM5Tb4KW04bFutVLCusd0Bt8sz0hNHA 4m5wUxtlDQPP2YRUQNiiN6OH6eOwmkk= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 061741A2D; Sun, 23 Mar 2025 21:19:53 -0700 (PDT) Received: from [10.162.16.153] (a077893.blr.arm.com [10.162.16.153]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B1B843F58B; Sun, 23 Mar 2025 21:19:41 -0700 (PDT) Message-ID: <48f15771-ed1a-4e30-b825-70ee3c323d37@arm.com> Date: Mon, 24 Mar 2025 09:49:38 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm64: mm: Correct the update of max_pfn To: Zhenhua Huang , catalin.marinas@arm.com, david@redhat.com, will@kernel.org, ryan.roberts@arm.com, mark.rutland@arm.com, ardb@kernel.org, yangyicong@hisilicon.com, joey.gouly@arm.com, quic_cgoldswo@quicinc.com, quic_sudaraja@quicinc.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, quic_tingweiz@quicinc.com References: <20250321070019.1271859-1-quic_zhenhuah@quicinc.com> Content-Language: en-US From: Anshuman Khandual In-Reply-To: <20250321070019.1271859-1-quic_zhenhuah@quicinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E8A5920003 X-Stat-Signature: x7c1kxfxfy9fzkprowxzs5tnif8uze7y X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1742789987-615783 X-HE-Meta: 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 yoX+S+ON w1diTOGVJ8tit6l5N8EAZd6WQS1aPwoJofpmcTtwlOL2+dt7qHG6xhwveDOwOjocVQYR74m+twQFrE3M7GFCHd3Gs+nFn3a9KOXl+hcMGFGZgYNUok7QOiWirqhlHzXYlN0sIBeY03fcQ7H/e/V9uwz7O9qqKD5IhkN7AqffHLkTK9DZsMnpAZ+/cAN4Tn2anakZpjjeZm6sj1Ns1XqqdZVQK1pdQYz4WA+vk2XE827SVipf2ZELkK1Wx/UwWFHyXaHhHuSTLubppZzAv+ZDIOJOX39b+u4blJ/l8SYPijB12HigWahH3lTek9g8MG9y5rEi0ypssiTsMS/rTOaH2bXNXAyw9wf2XqEKL 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: List-Subscribe: List-Unsubscribe: On 3/21/25 12:30, Zhenhua Huang wrote: > Hotplugged memory can be smaller than the original memory. For example, > on my target: > > root@genericarmv8:~# cat /sys/kernel/debug/memblock/memory > 0: 0x0000000064005000..0x0000000064023fff 0 NOMAP > 1: 0x0000000064400000..0x00000000647fffff 0 NOMAP > 2: 0x0000000068000000..0x000000006fffffff 0 DRV_MNG > 3: 0x0000000088800000..0x0000000094ffefff 0 NONE > 4: 0x0000000094fff000..0x0000000094ffffff 0 NOMAP > max_pfn will affect read_page_owner. Therefore, it should first compare and > then select the larger value for max_pfn. > > Fixes: 8fac67ca236b ("arm64: mm: update max_pfn after memory hotplug") > Signed-off-by: Zhenhua Huang > --- > arch/arm64/mm/mmu.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 1dfe1a8efdbe..310ff75891ef 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1361,7 +1361,8 @@ int arch_add_memory(int nid, u64 start, u64 size, > __remove_pgd_mapping(swapper_pg_dir, > __phys_to_virt(start), size); > else { > - max_pfn = PFN_UP(start + size); > + /* Address of hotplugged memory can be smaller */ > + max_pfn = max(max_pfn, PFN_UP(start + size)); > max_low_pfn = max_pfn; > } > Reviewed-by: Anshuman Khandual