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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E40DC77B61 for ; Mon, 24 Apr 2023 21:58:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A58296B0072; Mon, 24 Apr 2023 17:58:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A08486B0074; Mon, 24 Apr 2023 17:58:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8CF4F6B0075; Mon, 24 Apr 2023 17:58:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 7A43F6B0072 for ; Mon, 24 Apr 2023 17:58:28 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 4DA7E803E3 for ; Mon, 24 Apr 2023 21:58:28 +0000 (UTC) X-FDA: 80717649096.14.28BEF22 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf02.hostedemail.com (Postfix) with ESMTP id 97B8B80014 for ; Mon, 24 Apr 2023 21:58:26 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=DqPKH6tO; spf=pass (imf02.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 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=1682373506; 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=fKYrDa1ABjp9A/1j0g6ARfNwu3VzSLmuNZw1BK0LSzM=; b=lHxuuZI4qAyDB6wMv8GrpmitOw0ygverBae35kitD35QDSDCUbhQ6EXP/ujpKphpEB2Kr7 Svb2bh/LwiJ/PJskMdxDAdWZVLmeDOWke0z1kRsGTy3U4Jkn3juOtXpzqR1PCE+fTIobLn 0bRRnKbvXxuKcIktONg4XYjcVdhnph4= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=DqPKH6tO; spf=pass (imf02.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1682373506; a=rsa-sha256; cv=none; b=Ra5cG9bvbybMMxO0un0BNENwA/S/VNdIzFFjFHP1/1AyiK41QCAe2D4NpvUZPY1nFAsYNw khTNE05psZSehac+/3amqbP8qijIvM2boQhUZlt2TDQxKFSm/n0WG1137Q/coS9cuEtTIN sRzLBlnfBd4dZD58z3Rawk4p5Arz6FQ= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8AF5661F72; Mon, 24 Apr 2023 21:58:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E7A4C433EF; Mon, 24 Apr 2023 21:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1682373505; bh=GGIx+HG4RqLpRpWhwicWsnzwRbRDyOa6ai9UmyBpCL4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=DqPKH6tOcxN1rpWBfAP+OHlP6C3ty8wGvGNMxNEcqhAMTpFQWzhRcFgmjvzsD2iST +ayLkP6RlEH6L8SGKkhUoIisHVpcAGErbhUeQaaGMA5PA7AgyrJOFWL/2OLRfMrvoh EMEV/HZgqiOQSuYbsI5/soHCYkUyl3OhcalnvwAs= Date: Mon, 24 Apr 2023 14:58:23 -0700 From: Andrew Morton To: Matthew Wilcox Cc: Yajun Deng , david@redhat.com, osalvador@suse.de, gregkh@linuxfoundation.org, rafael@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] mmzone: Introduce for_each_populated_zone_pgdat() Message-Id: <20230424145823.b8e8435dd3242614371be6d5@linux-foundation.org> In-Reply-To: References: <20230424030756.1795926-1-yajun.deng@linux.dev> X-Mailer: Sylpheed 3.7.0 (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-Queue-Id: 97B8B80014 X-Stat-Signature: hskdqzimiq19s9f9hazyka8gzdgzsdir X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1682373506-978706 X-HE-Meta: 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 Nqb78h49 AmGFwd0RElZJVLuRxdWbm7HDZuyjbSgpWsu/8gM1QAKAz7sg94E8AzpF0B330On6hSjdZzluJwTTTpXc/1g8g57hXOCz+b7vcPPE+M5cRDkDl0GTHJAJtstwQcDIHZeUOLvpwRpJkhl69itEHjLwc1tN5/5PqqBOdYmKcOUaC/Hs5dNHgCo7muJdQ+sSsvmSjPaxYkCEWWErL5ZMWf801pFyTfltxMZ/c2oqS1sTNG5KCYzM7dAVmaCT1nNpfrb+5wSd36d2xfRazFoAYaNgpeNhSyH5HFkZIOCJdS0DtCF+JbYXdnO1OqQYsDHwTviO5ZonbtsoznyTEqxeqM20Pv5zsY4vd9o2hP1Yk6CDOUOpOVC2iieZjOmv0kXuFCLG5vTQ30BAKTQmtyorCEe7izuAOoloZuwXGD+QPyzvlCVx1kPSPgUSx1CE5GA== 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: On Mon, 24 Apr 2023 04:50:37 +0100 Matthew Wilcox wrote: > On Mon, Apr 24, 2023 at 11:07:56AM +0800, Yajun Deng wrote: > > Instead of define an index and determining if the zone has memory, > > introduce for_each_populated_zone_pgdat() helper that can be used > > to iterate over each populated zone in pgdat, and convert the most > > obvious users to it. > > I don't think the complexity of the helper justifies the simplification > of the users. Are you sure? > > +++ b/include/linux/mmzone.h > > @@ -1580,6 +1580,14 @@ extern struct zone *next_zone(struct zone *zone); > > ; /* do nothing */ \ > > else > > > > +#define for_each_populated_zone_pgdat(zone, pgdat, max) \ > > + for (zone = pgdat->node_zones; \ > > + zone < pgdat->node_zones + max; \ > > + zone++) \ > > + if (!populated_zone(zone)) \ > > + ; /* do nothing */ \ > > + else > > + But each of the call sites is doing this, so at least the complexity is now seen in only one place. btw, do we need to do the test that way? Why won't this work? #define for_each_populated_zone_pgdat(zone, pgdat, max) \ for (zone = pgdat->node_zones; \ zone < pgdat->node_zones + max; \ zone++) \ if (populated_zone(zone)) I suspect it was done the original way in order to save a tabstop, which is no longer needed.