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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A9496C433F5 for ; Wed, 11 May 2022 09:08:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=0oiPTf7VVuKXdZlloDVN3z0fBGJfcI4Myup8JrCSOY8=; b=fxJiGzid4v8reO ADYiOYEw6Nw4mCCTutguil+suWnvAdGyiaizfqDns9hoxfteP++JxkCwixGotWYR9llfsscikHmn8 blSl5W5U54xUhdzzqFg40NZYXBoEHsnO5zAyH0T+OhX2NsBTkeiIld9U3039QKrTjo25/q65Fscxw rEN1+xFOQigSAXxlbeV7jL26w64HsVcinYKO4r0gLSCyNMF7woZZp2asYAXV/isvXV73+FWjP2EOb Z4SNuY8Xs8DYU/XtTUXxBKiqUmXdH8pBRB+phhE+/gMTm9BgJTUQAo6t7dIMJEboamquuueLCHDcN gsQrTotPQMKDF0JgU3bA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1noiJK-0064c6-FZ; Wed, 11 May 2022 09:07:10 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1noiJE-0064a7-33 for linux-arm-kernel@lists.infradead.org; Wed, 11 May 2022 09:07:06 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652260021; 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=+6aR4G5bhHxoYCpwQyfjz1xkmAc7kDl/rLkC6zVA3qk=; b=c+y7WLQE+LkUW2q1S0fGfBHWOtKmYBLt6ZKvs9KCB0qdK7p9jsIkkFCzcvXlavUKevxXuB 9XvMLkoBRR5J0IrB3940fAARAeYcQYuB6YEaH452dlYxICt5NS4RSzNz6+4EbJT5tANsnL 8AnFkeAecOl6JE1CKngTaV+ifTBYOsk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-228-WkHv9DnJMvaF9c7uYKNQ9g-1; Wed, 11 May 2022 05:06:57 -0400 X-MC-Unique: WkHv9DnJMvaF9c7uYKNQ9g-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0C124804195; Wed, 11 May 2022 09:06:57 +0000 (UTC) Received: from localhost (ovpn-12-154.pek2.redhat.com [10.72.12.154]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CD872416539; Wed, 11 May 2022 09:06:55 +0000 (UTC) Date: Wed, 11 May 2022 17:06:51 +0800 From: Baoquan He To: Zhen Lei 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: References: <20220511032033.426-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220511032033.426-1-thunder.leizhen@huawei.com> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220511_020704_229803_50676EBB X-CRM114-Status: GOOD ( 28.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 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 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel