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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14419C433EF for ; Wed, 11 May 2022 10:06:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239197AbiEKKGr (ORCPT ); Wed, 11 May 2022 06:06:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239203AbiEKKGk (ORCPT ); Wed, 11 May 2022 06:06:40 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6B38D31237 for ; Wed, 11 May 2022 03:06:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652263593; 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: in-reply-to:in-reply-to:references:references; bh=lEm7VC0oh3/NhUfb651UmDt+6Cqjy8wZb5/iCmg68tE=; b=E+w3RTKGIoVZrcGgiwr5EMJLhR3GlfSV2mczUpYuhFvwXlKSIqMA6LhFbRb694EZ0FqLOm z/b+0dKxw97jZBf2R0/I/bCpKsuuyGJneysPWMsKCThDEhD9U+aC3LhCqIGlOCR2Jav3rk nxU7rpO2lv3c/JNETQjjw2LU5qTe+Cc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-475-R2X4UymDM5GtJrSkl4Bqgg-1; Wed, 11 May 2022 06:06:28 -0400 X-MC-Unique: R2X4UymDM5GtJrSkl4Bqgg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D14123C138B5; Wed, 11 May 2022 10:06:27 +0000 (UTC) Received: from localhost (ovpn-13-194.pek2.redhat.com [10.72.13.194]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BEF18C28114; Wed, 11 May 2022 10:06:26 +0000 (UTC) Date: Wed, 11 May 2022 18:06:23 +0800 From: Baoquan He To: "Leizhen (ThunderTown)" Cc: Dave Young , Vivek Goyal , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Jonathan Corbet , linux-doc@vger.kernel.org, "Eric W . Biederman" , Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , John Donnelly , Dave Kleikamp Subject: Re: [PATCH] arm64: kdump: Do not allocate crash low memory if not needed Message-ID: <20220511100623.GF122876@MiWiFi-R3L-srv> References: <20220511032033.426-1-thunder.leizhen@huawei.com> <8922e61e-ab7c-6e48-ad8c-57b75156a0f2@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8922e61e-ab7c-6e48-ad8c-57b75156a0f2@huawei.com> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 05/11/22 at 05:50pm, Leizhen (ThunderTown) wrote: > > > On 2022/5/11 17:06, Baoquan He wrote: > > On 05/11/22 at 11:20am, Zhen Lei wrote: > >> When "crashkernel=X,high" is specified, the specified "crashkernel=Y,low" > >> memory is not required in the following corner cases: > >> 1. If both CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32 are disabled, it means > >> that the devices can access any memory. > >> 2. If the system memory is small, the crash high memory may be allocated > >> from the DMA zones. If that happens, there's no need to allocate > >> another crash low memory because there's already one. > >> > >> Add condition '(crash_base >= CRASH_ADDR_LOW_MAX)' to determine whether > >> the 'high' memory is allocated above DMA zones. Note: when both > >> CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32 are disabled, the entire physical > >> memory is DMA accessible, CRASH_ADDR_LOW_MAX equals 'PHYS_MASK + 1'. > >> > >> Signed-off-by: Zhen Lei > >> --- > >> Documentation/admin-guide/kernel-parameters.txt | 5 +++-- > >> arch/arm64/mm/init.c | 3 ++- > >> 2 files changed, 5 insertions(+), 3 deletions(-) > >> > >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > >> index f6ff55840751a78..1b543c3109f4851 100644 > >> --- a/Documentation/admin-guide/kernel-parameters.txt > >> +++ b/Documentation/admin-guide/kernel-parameters.txt > >> @@ -823,7 +823,7 @@ > >> low memory is needed to make sure DMA buffers for 32-bit > >> devices won't run out. Kernel would try to allocate > >> at least 256M below 4G automatically. > >> - This one let user to specify own low range under 4G > >> + This one lets the user specify own low range under 4G > > ~ This one let users specify own low range ... > > > > Other than this nitpick, LGTM > > This is Catalin's response a few days ago: > Slightly more correct is "This one lets the user specify..." > > I didn't googled "This one lets", but I googled "It lets". I think he wrote it right. > > Both "the user" and "users" seem to be right. Yeah, I forgot the 'this one lets' part, and I am fine too with the 'the use'if it's right. So please ignore the comment. > > > > > > Acked-by: Baoquan He > > > >> for second kernel instead. > >> 0: to disable low allocation. > >> It will be ignored when crashkernel=X,high is not used > >> @@ -832,7 +832,8 @@ > >> [KNL, ARM64] range in low memory. > >> This one lets the user specify a low range in the > >> DMA zone for the crash dump kernel. > >> - It will be ignored when crashkernel=X,high is not used. > >> + It will be ignored when crashkernel=X,high is not used > >> + or memory reserved is located in the DMA zones. > >> > >> cryptomgr.notests > >> [KNL] Disable crypto self-tests > >> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > >> index 18ba66c90991ea0..ac510fb6a2c0189 100644 > >> --- a/arch/arm64/mm/init.c > >> +++ b/arch/arm64/mm/init.c > >> @@ -170,7 +170,8 @@ static void __init reserve_crashkernel(void) > >> return; > >> } > >> > >> - if (crash_low_size && reserve_crashkernel_low(crash_low_size)) { > >> + if ((crash_base >= CRASH_ADDR_LOW_MAX) && > >> + crash_low_size && reserve_crashkernel_low(crash_low_size)) { > >> memblock_phys_free(crash_base, crash_size); > >> return; > >> } > >> -- > >> 2.25.1 > >> > > > > . > > > > -- > Regards, > Zhen Lei >