From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f172.google.com (mail-pd0-f172.google.com [209.85.192.172]) by kanga.kvack.org (Postfix) with ESMTP id 0C8C86B0038 for ; Mon, 23 Sep 2013 13:11:19 -0400 (EDT) Received: by mail-pd0-f172.google.com with SMTP id z10so3482360pdj.3 for ; Mon, 23 Sep 2013 10:11:19 -0700 (PDT) Received: by mail-pa0-f51.google.com with SMTP id kp14so2499366pab.24 for ; Mon, 23 Sep 2013 09:36:40 -0700 (PDT) Message-ID: <52406E03.5060004@gmail.com> Date: Tue, 24 Sep 2013 00:36:19 +0800 From: Zhang Yanfei MIME-Version: 1.0 Subject: Re: [PATCH v3 1/5] memblock: Introduce allocation direction to memblock. References: <1379064655-20874-1-git-send-email-tangchen@cn.fujitsu.com> <1379064655-20874-2-git-send-email-tangchen@cn.fujitsu.com> <20130923153853.GC14547@htj.dyndns.org> In-Reply-To: <20130923153853.GC14547@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: Tang Chen , rjw@sisk.pl, lenb@kernel.org, tglx@linutronix.de, mingo@elte.hu, hpa@zytor.com, akpm@linux-foundation.org, toshi.kani@hp.com, zhangyanfei@cn.fujitsu.com, liwanp@linux.vnet.ibm.com, trenn@suse.de, yinghai@kernel.org, jiang.liu@huawei.com, wency@cn.fujitsu.com, laijs@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, mgorman@suse.de, minchan@kernel.org, mina86@mina86.com, gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com, lwoodman@redhat.com, riel@redhat.com, jweiner@redhat.com, prarit@redhat.com, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org Hello tejun, On 09/23/2013 11:38 PM, Tejun Heo wrote: > Hello, > > Sorry about the delay. Was traveling. hoho~ I guess you did have a good time. > > On Fri, Sep 13, 2013 at 05:30:51PM +0800, Tang Chen wrote: >> +/* Allocation order. */ >> +#define MEMBLOCK_DIRECTION_HIGH_TO_LOW 0 >> +#define MEMBLOCK_DIRECTION_LOW_TO_HIGH 1 >> +#define MEMBLOCK_DIRECTION_DEFAULT MEMBLOCK_DIRECTION_HIGH_TO_LOW > > Can we please settle on either top_down/bottom_up or > high_to_low/low_to_high? The two seem to be used interchangeably in > the patch series. Also, it'd be more customary to use enum for things > like above, but more on the interface below. OK. let's use top_down/bottom_up. And using enum is also ok. > >> +static inline bool memblock_direction_bottom_up(void) >> +{ >> + return memblock.current_direction == MEMBLOCK_DIRECTION_LOW_TO_HIGH; >> +} > > Maybe just memblock_bottom_up() would be enough? Agreed. > > Also, why not also have memblock_set_bottom_up(bool enable) as the > 'set' interface? hmmm, ok. So we will use memblock_set_bottom_up to replace memblock_set_current_direction below. > >> /** >> + * memblock_set_current_direction - Set current allocation direction to allow >> + * allocating memory from higher to lower >> + * address or from lower to higher address >> + * >> + * @direction: In which order to allocate memory. Could be >> + * MEMBLOCK_DIRECTION_{HIGH_TO_LOW|LOW_TO_HIGH} >> + */ >> +void memblock_set_current_direction(int direction); > > Function comments should go with the function definition. Dunno what > happened with set_current_limit but let's please not spread it. > >> +void __init_memblock memblock_set_current_direction(int direction) >> +{ >> + if (direction != MEMBLOCK_DIRECTION_HIGH_TO_LOW && >> + direction != MEMBLOCK_DIRECTION_LOW_TO_HIGH) { >> + pr_warn("memblock: Failed to set allocation order. " >> + "Invalid order type: %d\n", direction); >> + return; >> + } >> + >> + memblock.current_direction = direction; >> +} > > If set_bottom_up() style interface is used, the above will be a lot > simpler, right? Also, it's kinda weird to have two separate patches > to introduce the flag and actually implement bottom up allocation. Yeah, right, that'd be much simpler. And it is ok to put the two in one patch. Thanks. > > 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