From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f46.google.com (mail-pa0-f46.google.com [209.85.220.46]) by kanga.kvack.org (Postfix) with ESMTP id 94B166B0031 for ; Tue, 24 Sep 2013 10:19:41 -0400 (EDT) Received: by mail-pa0-f46.google.com with SMTP id fa1so5002571pad.5 for ; Tue, 24 Sep 2013 07:19:41 -0700 (PDT) Received: by mail-pb0-f47.google.com with SMTP id rr4so4634770pbb.34 for ; Tue, 24 Sep 2013 07:19:38 -0700 (PDT) Message-ID: <52419F63.6010504@gmail.com> Date: Tue, 24 Sep 2013 22:19:15 +0800 From: Zhang Yanfei MIME-Version: 1.0 Subject: Re: [PATCH 2/6] memblock: Introduce bottom-up allocation mode References: <524162DA.30004@cn.fujitsu.com> <524163CF.3010303@cn.fujitsu.com> <20130924121725.GC2366@htj.dyndns.org> <524190DC.4060605@gmail.com> <20130924132327.GH2366@htj.dyndns.org> <52419DC6.4030800@gmail.com> <20130924141640.GK2366@htj.dyndns.org> In-Reply-To: <20130924141640.GK2366@htj.dyndns.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Zhang Yanfei , "Rafael J . Wysocki" , lenb@kernel.org, Thomas Gleixner , mingo@elte.hu, "H. Peter Anvin" , Andrew Morton , Toshi Kani , Wanpeng Li , Thomas Renninger , Yinghai Lu , Jiang Liu , Wen Congyang , Lai Jiangshan , isimatu.yasuaki@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, Mel Gorman , Minchan Kim , mina86@mina86.com, gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com, lwoodman@redhat.com, Rik van Riel , jweiner@redhat.com, prarit@redhat.com, "x86@kernel.org" , linux-doc@vger.kernel.org, "linux-kernel@vger.kernel.org" , Linux MM , linux-acpi@vger.kernel.org, imtangchen@gmail.com On 09/24/2013 10:16 PM, Tejun Heo wrote: > Hello, > > On Tue, Sep 24, 2013 at 10:12:22PM +0800, Zhang Yanfei wrote: >> I see. I think it is rarely to fail. But here is case that it must >> fail in the current bottom-up implementation. For example, we allocate >> memory in reserve_real_mode() by calling this: >> memblock_find_in_range(0, 1<<20, size, PAGE_SIZE); >> >> Both the start and end is below the kernel, so trying bottom-up for >> this must fail. So I am now thinking that if we should take this as >> the special case for bottom-up. That said, if we limit start and end >> both below the kernel, we should allocate memory below the kernel instead >> of make it fail. The cases are also rare, in early boot time, only >> these two: >> >> |->early_reserve_e820_mpc_new() /* allocate memory under 1MB */ >> |->reserve_real_mode() /* allocate memory under 1MB */ >> >> How do you think? > > They need to be special cased regardless, right? It's wrong to print > out warning messages for things which are expected to behave that way. > Just skip bottom-up allocs if @end is under kernel image? > Good idea. Will do this way. -- Thanks. Zhang Yanfei -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org