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 79984C433F5 for ; Mon, 7 Feb 2022 14:51:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E4FC6B007D; Mon, 7 Feb 2022 09:50:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 896CC6B007E; Mon, 7 Feb 2022 09:50:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 735906B0080; Mon, 7 Feb 2022 09:50:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0117.hostedemail.com [216.40.44.117]) by kanga.kvack.org (Postfix) with ESMTP id 617AA6B007D for ; Mon, 7 Feb 2022 09:50:59 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 23786944DA for ; Mon, 7 Feb 2022 14:50:59 +0000 (UTC) X-FDA: 79116271038.13.3B150A2 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf25.hostedemail.com (Postfix) with ESMTP id ACD13A0002 for ; Mon, 7 Feb 2022 14:50:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644245458; h=from:from: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; bh=zikTiAYNsW3FX50KxVFGIBWDk9jSNH8ecGKPu+J72PI=; b=XYAQ4FmhpwgVApdzIE73CiTlTeE+fLNK7ja2EclE526kZxJokmEgSd99kWvQqKetJesivO h6j+FJSHAL8UI+vMiP3nnDXclXTPVM5nEj1WLQO6cj4lsydwaRyvjzmygNv5RlUI/SC2fy WmgvwipfMAGGzpWKNWyeVrZqPp5myzQ= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-610-2DnIC7K6NOqLyo_MrRr5rg-1; Mon, 07 Feb 2022 09:50:57 -0500 X-MC-Unique: 2DnIC7K6NOqLyo_MrRr5rg-1 Received: by mail-wm1-f69.google.com with SMTP id v185-20020a1cacc2000000b0034906580813so12369501wme.1 for ; Mon, 07 Feb 2022 06:50:56 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=zikTiAYNsW3FX50KxVFGIBWDk9jSNH8ecGKPu+J72PI=; b=oQ9F+iLPVoP9ApvHQvWDf49107Fi8q9nwe1EGrX7/fVCMz8REMPHu29FfWUF5hwW2S w3cRqMlTgvntgUG0pgNbyBpAfB6DJMiPmeOrRezwCzuXzb57Vo1dSLCnGi+Qzec9ZnZX 4eaSGC4gd9tKGCS5ZKGwF5GnOaR0QoqU7oEUM9b2cZwRiXQIzVx/vfU9Yed2w8OexzQj oiovdL4R3D25RFsHCL0nsa6KewTdADwmn175CxcGFI58qxddRD/uvDjEST+duv1ek/VH zw312Ld4kHuSFM1eYSGy8nO2P2k7BZs+SmKUL0DFZ2lkfmo9in3CEksCq0Y51pHg9UBF 5KnA== X-Gm-Message-State: AOAM530pZfSxHm3Zeb2KWLmG1p+9xfLoV+mC7uvKJDBJIhPZCJANWpuk Bvm/gjb0srGriMxViUzyrTxkGArSepvD5A/8P5oKbq4se8D528TcUZ6zj8efvzTpfMyk9AaSN0S oKcZhBEwqpxQ= X-Received: by 2002:a05:600c:28d2:: with SMTP id h18mr10299115wmd.56.1644245455841; Mon, 07 Feb 2022 06:50:55 -0800 (PST) X-Google-Smtp-Source: ABdhPJyLpe2hgXZ2il+Wvv9VULju4pkFVV31oFWKYZl79U3Bxo66VYH7T4BN2SHO+24n0lcDktcc6g== X-Received: by 2002:a05:600c:28d2:: with SMTP id h18mr10299106wmd.56.1644245455667; Mon, 07 Feb 2022 06:50:55 -0800 (PST) Received: from ?IPV6:2003:cb:c709:6300:a751:d742:1f76:8639? (p200300cbc7096300a751d7421f768639.dip0.t-ipconnect.de. [2003:cb:c709:6300:a751:d742:1f76:8639]) by smtp.gmail.com with ESMTPSA id l10sm11993306wry.79.2022.02.07.06.50.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Feb 2022 06:50:55 -0800 (PST) Message-ID: Date: Mon, 7 Feb 2022 15:50:54 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH 2/4] mm/memory_hotplug: avoid calling zone_intersects() for ZONE_NORMAL To: Miaohe Lin , akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220207133643.23427-1-linmiaohe@huawei.com> <20220207133643.23427-3-linmiaohe@huawei.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20220207133643.23427-3-linmiaohe@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: ibrsq13139igh96nhueg1h1gox1sdghm X-Rspam-User: nil Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=XYAQ4Fmh; spf=none (imf25.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: ACD13A0002 X-HE-Tag: 1644245458-163666 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 07.02.22 14:36, Miaohe Lin wrote: > If zid reaches ZONE_NORMAL, the caller will always get the NORMAL zone no > matter what zone_intersects() returns. So we can save some possible cpu > cycles by avoid calling zone_intersects() for ZONE_NORMAL. > > Signed-off-by: Miaohe Lin > --- > mm/memory_hotplug.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index cbc67c27e0dd..140809e60e9a 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -826,7 +826,7 @@ static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn > struct pglist_data *pgdat = NODE_DATA(nid); > int zid; > > - for (zid = 0; zid <= ZONE_NORMAL; zid++) { > + for (zid = 0; zid < ZONE_NORMAL; zid++) { > struct zone *zone = &pgdat->node_zones[zid]; > > if (zone_intersects(zone, start_pfn, nr_pages)) Makes sense, although we just don't care about the CPU cycles at that point. Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb