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 X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD4B9C4363D for ; Wed, 23 Sep 2020 06:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FC76221E8 for ; Wed, 23 Sep 2020 06:05:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YibiQrDc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726631AbgIWGFL (ORCPT ); Wed, 23 Sep 2020 02:05:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60681 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726179AbgIWGFL (ORCPT ); Wed, 23 Sep 2020 02:05:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600841109; h=from:from:reply-to: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=rYJ+scwxgIVdLM3G4UWy3vWMdK97SIs3I3Rw635Z5+0=; b=YibiQrDcADD57j5CTAz1OT+fdaJDQ7yfmbPyXoviQfhYgWFkTBh2EFbtXUl9HLfQbiELzd qCxOEvxnjY0ASKlmLb/P+CPknhcHSTQQpO7u3jTPxxfWri3Ch8B89U7lJNjJzkguy8mbVN 4o/sE5KSUmuVAMx3CYKLhcFiQ8mh3DQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-433-26iReUI8O-uYBr6EjlCYLQ-1; Wed, 23 Sep 2020 02:05:03 -0400 X-MC-Unique: 26iReUI8O-uYBr6EjlCYLQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A0F81188C132; Wed, 23 Sep 2020 06:05:01 +0000 (UTC) Received: from [10.64.54.30] (vpn2-54-30.bne.redhat.com [10.64.54.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EA40219C4F; Wed, 23 Sep 2020 06:04:58 +0000 (UTC) Reply-To: Gavin Shan Subject: Re: [PATCH V3 1/3] arm64/mm/hotplug: Register boot memory hot remove notifier earlier To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org Cc: Mark Rutland , Will Deacon , catalin.marinas@arm.com, Steve Capper , linux-kernel@vger.kernel.org, Mark Brown , Marc Zyngier , will@kernel.org References: <1600689908-28213-1-git-send-email-anshuman.khandual@arm.com> <1600689908-28213-2-git-send-email-anshuman.khandual@arm.com> From: Gavin Shan Message-ID: Date: Wed, 23 Sep 2020 16:04:56 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <1600689908-28213-2-git-send-email-anshuman.khandual@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Anshuman, On 9/21/20 10:05 PM, Anshuman Khandual wrote: > This moves memory notifier registration earlier in the boot process from > device_initcall() to early_initcall() which will help in guarding against > potential early boot memory offline requests. Even though there should not > be any actual offlinig requests till memory block devices are initialized > with memory_dev_init() but then generic init sequence might just change in > future. Hence an early registration for the memory event notifier would be > helpful. While here, just skip the registration if CONFIG_MEMORY_HOTREMOVE > is not enabled and also call out when memory notifier registration fails. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Mark Rutland > Cc: Marc Zyngier > Cc: Steve Capper > Cc: Mark Brown > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > arch/arm64/mm/mmu.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > With the following nit-picky comments resolved: Reviewed-by: Gavin Shan > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62fea1b6..df3b7415b128 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1499,7 +1499,17 @@ static struct notifier_block prevent_bootmem_remove_nb = { > > static int __init prevent_bootmem_remove_init(void) > { > - return register_memory_notifier(&prevent_bootmem_remove_nb); > + int ret = 0; > + > + if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) > + return ret; > + > + ret = register_memory_notifier(&prevent_bootmem_remove_nb); > + if (!ret) > + return ret; > + > + pr_err("Notifier registration failed - boot memory can be removed\n"); > + return ret; > } It might be cleaner if the duplicated return statements can be avoided. Besides, it's always nice to print the errno even though zero is always returned from register_memory_notifier(). So I guess you probably need something like below: ret = register_memory_notifier(&prevent_bootmem_remove_nb); if (ret) pr_err("%s: Error %d registering notifier\n", __func__, ret) return ret; register_memory_notifier # 0 is returned on !CONFIG_MEMORY_HOTPLUG_SPARSE blocking_notifier_chain_register notifier_chain_register # 0 is always returned > -device_initcall(prevent_bootmem_remove_init); > +early_initcall(prevent_bootmem_remove_init); > #endif > Cheers, Gavin