From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D904E314A9F for ; Mon, 15 Dec 2025 09:22:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765790546; cv=none; b=UHX/GHCzE4JCBK+dOXAjupCOxRjbl1tZ6a1xjJ7YmQ9XV4kAUxDvYIMcFy1EUEr0X9IH3xLUpK3SXsPPGM4YWHFC9HQ7nZLYbgCOZJOizdTcoup/MS4S3cMTf5N0fc9G7Onjq7LgnpE2TA99nqFljWL2aO999S1Fs4xD8P/R1N0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765790546; c=relaxed/simple; bh=rRgk/jKyq3Xc+z294BSrYdB5EGZbteu2gYXGFcGqquw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HbHgS3Kcj2sOa7lmRxV2zcVIQ+iaMDymuhJwOWNmfiwSPOkHShLqv5NC1nYX4g931fVWRu2CFnWOg6/DOKyf3Zx6DKA5OFnojXSgXEBLj4nxJiADl512xjbUt8EteLAxF7LfRUyRtlAqD1eULZxLMZGWZLXjfIVt9ruhmYkSMbc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=J1hhOrw/; arc=none smtp.client-ip=209.85.208.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="J1hhOrw/" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-649729effd7so4309248a12.0 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=vger.kernel.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=J1hhOrw/8M2Se6/m0bGqpXY8UkWEM1ckvf/oW11Mzwma0wxV06Wbq90JpPDD8l/0ci BeJsEtvt4BfL+rWxs6795aOQbmE9KAGKxmJehKKVMJt46VMoZyt8BHEmz6MeA4dTqi55 TJE8L5TmRbZx+f8chM0QN1UHUFcOjfzibWeJm00RCn/qa5/D1QrUfdDYS+y12Ub0PDaW n4KHc29SffuwHK219o4Udp8i7KTYY+vYu5f7D4cK8bj92j1nKTlH1qAUph1qZDK13ftr Ez4wMB/GzpvIb+vttHZdsmb5mj2jpo9DKVgXluqqPAsm1Hpdnbexs36yFT9Ff0tCQAk4 rEYw== 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=rFPKYdhLMHK4s7mPQ5mG0rWAouyfV0x+sulWT43s5e3Hc90fhAab/3IEK5x2jUq1XS Xeh0vj3eE5R2i2plu9RFkjWjl5pQkwx1ExNYwVYiIaPRMpUZNwjGNMjZrDIoKPjzkoDC Sc0CvKtxE1YM/5Klc+R+hLqA7OBE1yd4m9DRMOHQX4MDeOaZABdupiiNXKZ/tq2AErdO GRyrLdH7leHmhy6MWPu/MFqiB2M0KrfhD3Sgavpm5MnkFg542Nf5qKAS/ttnWncesV79 6Ap3JF91PYD+Wd6byYL8oxS4jbgmiY70ybAE3xk+YjfFDFVGVIjac18ESEA3SaJeRrXp SHfQ== X-Forwarded-Encrypted: i=1; AJvYcCWMTo6qXiYkwRX1frofrVYD6Z+Xaxye6UKyYgJNcgBefWw2BoeX/Ez9W95uO609VGZFjMXiAz4HNV0MsgA=@vger.kernel.org X-Gm-Message-State: AOJu0YwdkSoWScF5zifzdNXVXf0doJrSbEP3C7h6OJIU45FgZf7SywJl OINAL+SdsRa5sDykhVapzDIAU0zzHYWKtqFqESlOy85Ytp/pUOTiZ/T5Y2arSbt05tLcPNozNNW 3y8XwvUoS7pDD4g== 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: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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" 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?