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 08168C54FD4 for ; Wed, 29 Jul 2026 20:27:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4DE4C6B0088; Wed, 29 Jul 2026 16:27:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 48F306B008A; Wed, 29 Jul 2026 16:27:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 37DE26B008C; Wed, 29 Jul 2026 16:27:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 0B3856B0088 for ; Wed, 29 Jul 2026 16:27:51 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 801A5160617 for ; Wed, 29 Jul 2026 20:27:50 +0000 (UTC) X-FDA: 85042950300.29.75896CD Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf05.hostedemail.com (Postfix) with ESMTP id 59602100006 for ; Wed, 29 Jul 2026 20:27:48 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=pmxruMJ1; spf=pass (imf05.hostedemail.com: domain of akpm@linux-foundation.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785356868; b=Iv4fNVDc5AKYXTi/AujDe+lD2jNS6RfOB/AIuN1syvAdwQl9nnZOaQ7vEGWeomC5wxrjzY VG1bq5G7t88mGxFwT5vGmXGfV7nsDhCzMg7N4G/VTfYKGjKE45l4POwxLJaJfw1P8+QRue +DmSPw0jmEX7P7/3Hh+aHSg8Z59gueI= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=pmxruMJ1; spf=pass (imf05.hostedemail.com: domain of akpm@linux-foundation.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785356868; 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:dkim-signature; bh=ppvXWw17La6VOhnrUygWlQUgfnpDHFiES+LHiGhQI9o=; b=Fn8MvCZZoCNel8ZX1V+64mnDgvMmNh9ZslffmO6m8U8O5kSNs1hcYZriruRgzFudL9dp4z xbfaD4NBMpoBk5nZ0hg8J6g8WmUtyl5vgOWsvJ8WC1tdAaAYQ8JduO5yF7nuDrQW9lhiHF /kOGb4PcDfoT5VDNynTDwv9Ix5NGDMQ= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 9D2A240A83; Wed, 29 Jul 2026 20:27:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66E271F000E9; Wed, 29 Jul 2026 20:27:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785356866; bh=ppvXWw17La6VOhnrUygWlQUgfnpDHFiES+LHiGhQI9o=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=pmxruMJ1yZLHx156OsbBp5gSVtDIshq8dIJXFa0BYpRSUQMI0R9ZN9xgqRInVpm+M blUfS8rXikZOjCy7G6aFkQwC8FOE4J6NolSJaMupWS+16a0l/XZNdel0ZvkErIJ22V H3EHiCuOk7dtzRJDq9pAccwcW/qReTxBpkmPW3VE= Date: Wed, 29 Jul 2026 13:27:45 -0700 From: Andrew Morton To: Sang-Heon Jeon Cc: Mike Rapoport , linux-mm@kvack.org Subject: Re: [PATCH] mm/mm_init: remove unnecessary initialization of pgdat->per_cpu_nodestats Message-Id: <20260729132745.9d42a13e614be2e18c5988ba@linux-foundation.org> In-Reply-To: <20260729155143.177790-1-ekffu200098@gmail.com> References: <20260729155143.177790-1-ekffu200098@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (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: rspam12 X-Rspamd-Queue-Id: 59602100006 X-Stat-Signature: eq4dt8wzkkqad9e5em1k6ckgat57abm8 X-Rspam-User: X-HE-Tag: 1785356868-430274 X-HE-Meta: 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 MRep2x4t xSHW62n9ZGtbU+/5XMVUjX1YOCJgiwS8P9jnVL4+DvZiNrQJ71YSkEjHhIebz5zD7xAGCONX0RAQRn1P3bXWyboeRgGOOyYomv5pAFykvEWFSslzbPFF6w+P/TUM/IIB2Rs6w6X/WRZLTi8/zr5T1SFRxp2plGR85qPJE8CaxSffM9ranYbTnHswDk8sPOT5PLM/eY+aeyVUtdvie2QwjW9bRzk9cFPZJJJrxZrQmA6tMzb4Yey0ppQDCc96OpQ43Cv6ZNYk7ehDkfzusHRddvhj/BVnT4SK8Rwfqel1/oNJclgG2ibeA/cxDVjijQHXECq+V Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 30 Jul 2026 00:51:15 +0900 Sang-Heon Jeon wrote: > free_area_init_node() sets pgdat->per_cpu_nodestats to NULL and later > calls free_area_init_core(), which unconditionally overwrites it with > &boot_nodestats. Nothing reads the field in between, so the store has > no effect. > > Remove unnecessary initialization. No functional change. > > ... > > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -1722,7 +1722,6 @@ static void __init free_area_init_node(int nid) > > pgdat->node_id = nid; > pgdat->node_start_pfn = start_pfn; > - pgdat->per_cpu_nodestats = NULL; > > if (start_pfn != end_pfn) { > pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid, Looks OK, thanks. Although this statement is "free" in __init code and its removal does make the code that bit harder to follow. Possibly *pgdat was zeroed out anyway, I got bored figuring that out. The memblock_alloc_range_nid() kerneldoc is silent on the state of the returned memory but I spy a kzalloc_node() in there.