From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10162134C7 for ; Tue, 19 Dec 2023 07:28:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fpRltdt3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1702970938; 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=z41OPAeFuRVfVwpG8mOU7SweUlkIZGPKy5DQ+DlmDTM=; b=fpRltdt3jAhImnH+tKZA6Exc53KP8Kiiq9S7DUtSR7ukgV/L1XIfGkDwII4Dahdf4TTyba yAkU3m+F4NPykvDgOhM9CZMo1Ca1RA8SCEKzjHdYhZcjHoc5VdWQ4rqZLJW3ymTXGvZfir SVKVdQcT0phOTtPMsJ3jnvgz5uU+8o4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-407-GXz9a8nTNNqDb8SpWVPjkw-1; Tue, 19 Dec 2023 02:28:56 -0500 X-MC-Unique: GXz9a8nTNNqDb8SpWVPjkw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B1E92848C02; Tue, 19 Dec 2023 07:28:55 +0000 (UTC) Received: from localhost (unknown [10.72.116.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 05E791121306; Tue, 19 Dec 2023 07:28:54 +0000 (UTC) Date: Tue, 19 Dec 2023 15:28:51 +0800 From: Baoquan He To: Pingfan Liu Cc: kexec@lists.infradead.org, linux-doc@vger.kernel.org, Pingfan Liu , Dave Young Subject: Re: [PATCH] Documentation: kdump: Clarify the default size of memory reserved by crashkernel low Message-ID: References: <20231218034020.15341-1-kernelfans@gmail.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231218034020.15341-1-kernelfans@gmail.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 On 12/18/23 at 11:40am, Pingfan Liu wrote: > From: Pingfan Liu > > The default size reserved for crashkernel=,low is decided by the macro > DEFAULT_CRASH_KERNEL_LOW_SIZE, which is based on arch. > > Signed-off-by: Pingfan Liu > Cc: Baoquan He > Cc: Dave Young > To: kexec@lists.infradead.org > To: linux-doc@vger.kernel.org > --- > Documentation/admin-guide/kdump/kdump.rst | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst > index 5762e7477a0c..a021ff155012 100644 > --- a/Documentation/admin-guide/kdump/kdump.rst > +++ b/Documentation/admin-guide/kdump/kdump.rst > @@ -310,8 +310,9 @@ crashkernel syntax > region above 4G, low memory under 4G is needed in this case. There are > three ways to get low memory: > > - 1) Kernel will allocate at least 256M memory below 4G automatically > - if crashkernel=Y,low is not specified. > + 1) Kernel will allocate a chunk of default size memory, which is based on > + architecture, below 4G automatically if crashkernel=Y,low is not > + specified. Good catch, thx. Acked-by: Baoquan He > 2) Let user specify low memory size instead. > 3) Specified value 0 will disable low memory allocation:: > > -- > 2.31.1 >