From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1C1AFD59D99 for ; Mon, 15 Dec 2025 09:22:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 630376B0006; Mon, 15 Dec 2025 04:22:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5B9836B0007; Mon, 15 Dec 2025 04:22:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 481526B0008; Mon, 15 Dec 2025 04:22:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 345946B0006 for ; Mon, 15 Dec 2025 04:22:27 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id CBDC813C4A1 for ; Mon, 15 Dec 2025 09:22:26 +0000 (UTC) X-FDA: 84221164692.19.35E6AF5 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) by imf24.hostedemail.com (Postfix) with ESMTP id E436C180013 for ; Mon, 15 Dec 2025 09:22:24 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=ABzS0OGv; spf=pass (imf24.hostedemail.com: domain of 3T9M_aQgKCEYriksuivjowwotm.kwutqv25-uus3iks.wzo@flex--jackmanb.bounces.google.com designates 209.85.208.74 as permitted sender) smtp.mailfrom=3T9M_aQgKCEYriksuivjowwotm.kwutqv25-uus3iks.wzo@flex--jackmanb.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1765790545; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rRgk/jKyq3Xc+z294BSrYdB5EGZbteu2gYXGFcGqquw=; b=6uO8A3trUcYxHGBORiyKED22HLGYYEoSXakyGXUY3tfLlfmhYVLG/QwBJHVqIPhXOPyjuP wpXsb7pgQ3u7KI4Sv8qnlFiyz9Ov3reNVyqmlF++dkJ6j8J4Y8FBAWsMKnYxLAenOCP0tK jIO/w2G6+EqwpxrFofb4U99PBLEWzZA= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=ABzS0OGv; spf=pass (imf24.hostedemail.com: domain of 3T9M_aQgKCEYriksuivjowwotm.kwutqv25-uus3iks.wzo@flex--jackmanb.bounces.google.com designates 209.85.208.74 as permitted sender) smtp.mailfrom=3T9M_aQgKCEYriksuivjowwotm.kwutqv25-uus3iks.wzo@flex--jackmanb.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1765790545; a=rsa-sha256; cv=none; b=Tb/1FgbnsCv7xM7dY/rQHU3zz6jHlyh4w9bcC5efkF2OrO98WwQs6li6OFiy4mIWZMXWiP A2WkKvG/1EuXbIxUIv/NSoe6PUIpXBMG08Wmy2pwsLgLTtkJhn4tEE+SjzN/wBD0XeRyLA lt4jvwmaLMWi/qslvA1+uNkk/kOM1fs= Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-6495cc3e622so3896141a12.2 for ; Mon, 15 Dec 2025 01:22:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1765790543; x=1766395343; darn=kvack.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=rRgk/jKyq3Xc+z294BSrYdB5EGZbteu2gYXGFcGqquw=; b=ABzS0OGvD5JvsnB0Efs+UBdH4pN1RqdKrI0odNTHxXZbSsgVs2NvMbM3I9l3sky4Py qPX4qlYNWCjZ2xN2jgw+Zdlv6YAmsPGwGO7l8hSUTd230TfQ4futI2g0SQhJuzclsZdl ai/4h2PnE/K8iqCKn2C756xaamnAvQvYNsql3AbqtF/8BjgLzPQt1rB5E4xtbwv1xdlI bRcD8yoAUxdqBVC0kb2YRTUAfd8HDFS/uQ93aNHPoiS0l2sw4iA+mB3+K2saoWXsE+HT 4OUkArNq/PueU08ZK1C9bKBBqO22HL37UdnGtgI0Sh/CX7f/AKhy6JuA4VI1Ca4LgyZD 81Og== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765790543; x=1766395343; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=rRgk/jKyq3Xc+z294BSrYdB5EGZbteu2gYXGFcGqquw=; b=VCLyRq/PNMprLwrnCVAzJqaGw0n9m3InB2KMI6Qi2S/OiHfPhSZzV/OePVwBulAVkX RPZRc13B2Tj5M6iBoMhXrl3ZS1V9EBHirchN43xY7W1u6ACjHGimuUkiHuVDynvPMX2E pWX8DHBRTFEHG+Kori8LMOPuJaRfdYtxkwiSCkFenbCyZUyHEk0sf9s0O8RHe0SYRKx+ PyPAoIKG6b9lYNWO6sFXftec5S+1N43V0BDAFGe3M40jNoCCPIErBHuVjyYD9PDX8bYE ClpgK0lYUvK9/PGMkispG4UBYeBBD2KT3rVzMda9pktwtg2D++JnWQNGWRd1N722UpwQ UKqA== X-Forwarded-Encrypted: i=1; AJvYcCXrv+gG0Izs7d73VCHm7nujsP1FPVMsx42ngHjy+Q0VzU1g9iJaWWtMn8+XoP9JVvLVnGyK5wK92Q==@kvack.org X-Gm-Message-State: AOJu0Yzxc1MiWhX7y+Z0Pzfv/ZQXh9xV1NsfJ170QlxVMFwuTxGB+pvj PdjRC/O/ItI5bAdKmFygbOKLSuCxDwcg7uGU8oAKuXb+gmhri40m0LbXNTQ3GRsvHs08GvmK7fD lqBzaIsw2LxleeA== X-Google-Smtp-Source: AGHT+IGqA6/7NhdOmRJlayZuRkq/89Snr/0cKuIgnNpYQ1catSJLJfZQNQG1cjXYcwltRqxHcaD6SGiYTjuK7g== X-Received: from edbdy7.prod.google.com ([2002:a05:6402:31e7:b0:649:8456:d4bf]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:4312:b0:649:62e1:10ca with SMTP id 4fb4d7f45d1cf-6499b1d86bfmr9525174a12.27.1765790543128; Mon, 15 Dec 2025 01:22:23 -0800 (PST) Date: Mon, 15 Dec 2025 09:22:22 +0000 In-Reply-To: Mime-Version: 1.0 References: <20251212161832.2067134-1-yeoreum.yun@arm.com> <20251212161832.2067134-3-yeoreum.yun@arm.com> X-Mailer: aerc 0.21.0 Message-ID: Subject: Re: [PATCH 2/2] arm64: mmu: use pagetable_alloc_nolock() while stop_machine() From: Brendan Jackman To: Yeoreum Yun , Brendan Jackman Cc: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: yenwq8q4pfxwtrp6q1jnzeq168edj945 X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: E436C180013 X-HE-Tag: 1765790544-713481 X-HE-Meta: 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 VxHNUdM5 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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: List-Subscribe: List-Unsubscribe: On Sun Dec 14, 2025 at 9:13 AM UTC, Yeoreum Yun wrote: >> I don't have the context on what this code is doing so take this with >> a grain of salt, but... >> >> The point of the _nolock alloc is to give the allocator an excuse to >> fail. Panicking on that failure doesn't seem like a great idea to me? > > I thought first whether it changes to "static" memory area to handle > this in PREEMPT_RT. > But since this function is called while smp_cpus_done(). > So, I think it's fine since there wouldn't be a contention for > memory allocation in this phase. Then shouldn't it use _nolock unconditionally?