From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f177.google.com (mail-pd0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id BD83D6B0032 for ; Thu, 26 Sep 2013 11:37:55 -0400 (EDT) Received: by mail-pd0-f177.google.com with SMTP id y10so1305245pdj.8 for ; Thu, 26 Sep 2013 08:37:55 -0700 (PDT) Received: by mail-pd0-f178.google.com with SMTP id w10so1320704pde.37 for ; Thu, 26 Sep 2013 08:37:52 -0700 (PDT) Message-ID: <524454BE.4030602@gmail.com> Date: Thu, 26 Sep 2013 23:37:34 +0800 From: Zhang Yanfei MIME-Version: 1.0 Subject: Re: [PATCH v5 2/6] memblock: Introduce bottom-up allocation mode References: <5241D897.1090905@gmail.com> <5241D9A4.4080305@gmail.com> <20130926144516.GD3482@htj.dyndns.org> In-Reply-To: <20130926144516.GD3482@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: "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, Zhang Yanfei Hello tejun, Thanks for your quick comments first:) On 09/26/2013 10:45 PM, Tejun Heo wrote: > Hello, > > On Wed, Sep 25, 2013 at 02:27:48AM +0800, Zhang Yanfei wrote: >> +#ifdef CONFIG_MOVABLE_NODE >> +static inline void memblock_set_bottom_up(bool enable) >> +{ >> + memblock.bottom_up = enable; >> +} >> + >> +static inline bool memblock_bottom_up(void) >> +{ >> + return memblock.bottom_up; >> +} > > Can you please explain what this is for here? OK, will do. > >> + /* >> + * we always limit bottom-up allocation above the kernel, >> + * but top-down allocation doesn't have the limit, so >> + * retrying top-down allocation may succeed when bottom-up >> + * allocation failed. >> + * >> + * bottom-up allocation is expected to be fail very rarely, >> + * so we use WARN_ONCE() here to see the stack trace if >> + * fail happens. >> + */ >> + WARN_ONCE(1, "memblock: Failed to allocate memory in bottom up " >> + "direction. Now try top down direction.\n"); >> + } > > You and I would know what was going on and what the consequence of the > failure may be but the above warning message is kinda useless to a > user / admin, right? It doesn't really say anything meaningful. > Hmmmm.. May be something like this: WARN_ONCE(1, "Failed to allocated memory above the kernel in bottom-up," "so try to allocate memory below the kernel."); Thanks -- 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