From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f42.google.com (mail-la0-f42.google.com [209.85.215.42]) by kanga.kvack.org (Postfix) with ESMTP id 01EEB6B0036 for ; Sat, 16 Aug 2014 10:40:51 -0400 (EDT) Received: by mail-la0-f42.google.com with SMTP id pv20so3183586lab.29 for ; Sat, 16 Aug 2014 07:40:51 -0700 (PDT) Received: from szxga02-in.huawei.com ([119.145.14.65]) by mx.google.com with ESMTPS id l6si17224164lbr.4.2014.08.16.07.40.48 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sat, 16 Aug 2014 07:40:50 -0700 (PDT) Message-ID: <53EF6C79.3000603@huawei.com> Date: Sat, 16 Aug 2014 22:36:41 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: Re: [PATCH] mem-hotplug: let memblock skip the hotpluggable memory regions in __next_mem_range() References: <53E8C5AA.5040506@huawei.com> <20140816130456.GH9305@htj.dyndns.org> In-Reply-To: <20140816130456.GH9305@htj.dyndns.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Andrew Morton , Tang Chen , Zhang Yanfei , Wen Congyang , "Rafael J. Wysocki" , "H. Peter Anvin" , Linux MM , LKML On 2014/8/16 21:04, Tejun Heo wrote: > On Mon, Aug 11, 2014 at 09:31:22PM +0800, Xishi Qiu wrote: >> Let memblock skip the hotpluggable memory regions in __next_mem_range(), >> it is used to to prevent memblock from allocating hotpluggable memory >> for the kernel at early time. The code is the same as __next_mem_range_rev(). >> >> Clear hotpluggable flag before releasing free pages to the buddy allocator. > > Please try to explain "why" in addition to "what". Why do we need to > clear hotpluggable flag in free_low_memory_core_early() in addition to > numa_clear_node_hotplug() in x86 numa.c? Does this make x86 code > redundant? If not, why? > Hi Tejun, numa_clear_node_hotplug()? There is only numa_clear_kernel_node_hotplug(). If we don't clear hotpluggable flag in free_low_memory_core_early(), the memory which marked hotpluggable flag will not free to buddy allocator. Because __next_mem_range() will skip them. free_low_memory_core_early for_each_free_mem_range for_each_mem_range __next_mem_range Thanks, Xishi Qiu -- 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