From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C48439B97B; Thu, 10 Sep 2026 08:33:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789029240; cv=none; b=VAir1qc5Y9CMPZpoxw3/tPwQWfgsT8pQR2UbO+MoCcocq3zDivM/wlrq8zLQlDF8Yi3wqc7Pg3cQN++wJW9b7kc8zBgS0p+ONjZBTRs6Fu4xWAFvKcHlODAyEtn7yDYlA9dQpvaBjUbcsteKrK2E2fI9y0YY8iFsHWmOKtznvPo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789029240; c=relaxed/simple; bh=boajKtpJSSsvTCcjGW9fP/zFWBeiC+tyHKsXcd8ZiIg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Z+BMjEYeN24pVUnHpFhArYbzM3meDr+W0OJCjyMwojf7+WtQ67M7uk4sUZ+ymfISlKIAzizfh22Ov2FuQU3OelKveth1oA3FgQYWk3JFVPcwHPp6LPW3SDTLnT09OsVn4RvfZyH1PuinAZUHkM4c/OanrVouFxxtcHwMKfrICvA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CazkhZSv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CazkhZSv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA8C81F000FF; Thu, 10 Sep 2026 08:33:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789029239; bh=htWrCuWloy0NONsft45RDstF/ATea72DavKG8+QtMK4=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=CazkhZSvT+O0NgogGiXHI0lYcotwsei+QChUnDurF+HYFaqB31jqAAsP+ioj1RnJa slgoF+ChAAr/n4Lv1nBu2JaW3o+ffaESC4PwPQHVefTX1rJX0ZIIobfByVZPcIh8yU cx/VjCtD++UBLeRhzdko4P4UG+Pz1IlPG0jvfelVuUSkAqdjNHPkX4ImE2iLnVR4zh ECN3fzt4IyI8LStfLku08boRFArVqEJj1jo7jmqw3U74L2Mq2EXSNraAwkdMbliJHb jqTXTw4P0h0kyaFkuFMztWx28m4l1WJ72RCkKhiHM7UOl5XVdmfYEX46V1wJWF6/8J lsV+jOV4QvQfw== Date: Thu, 10 Sep 2026 10:33:50 +0200 From: "Oscar Salvador (SUSE)" To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , Brendan Jackman , Johannes Weiner , Zi Yan , Oscar Salvador , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Jan Kiszka , Kieran Bingham , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 08/12] mm/sparse: move __highest_used_section_nr handling Message-ID: References: <20260909-b4-sparsemem_cleanups-v1-0-008fc8d579fe@kernel.org> <20260909-b4-sparsemem_cleanups-v1-8-008fc8d579fe@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260909-b4-sparsemem_cleanups-v1-8-008fc8d579fe@kernel.org> On Wed, Sep 09, 2026 at 03:33:01PM +0200, David Hildenbrand (Arm) wrote: > Let's move it to sparse_init_one_section(). However, to keep early > boot processing working, we also have to initialize it in > sparse_sections_init(). > > Should we use READ_ONCE/WRITE_ONCE with __highest_used_section_nr? > Probably, something for another day. What is the worry there? sparse_init_one_section() calls should run sequentally due to the memhotplug lock, so there should not be parallel updates there? -- Oscar Salvador SUSE Labs