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Date: Sun, 17 Aug 2014 07:08:21 -0400
From: Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH] mem-hotplug: let memblock skip the hotpluggable memory
 regions in __next_mem_range()
Message-ID: <20140817110821.GM9305@htj.dyndns.org>
References: <53E8C5AA.5040506@huawei.com>
 <20140816130456.GH9305@htj.dyndns.org>
 <53EF6C79.3000603@huawei.com>
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To: Xishi Qiu <qiuxishi@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Tang Chen <tangchen@cn.fujitsu.com>, Zhang Yanfei <zhangyanfei@cn.fujitsu.com>, Wen Congyang <wency@cn.fujitsu.com>, "Rafael J. Wysocki" <rjw@sisk.pl>, "H. Peter Anvin" <hpa@zytor.com>, Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>

Hello,

On Sat, Aug 16, 2014 at 10:36:41PM +0800, Xishi Qiu wrote:
> numa_clear_node_hotplug()? There is only numa_clear_kernel_node_hotplug().

Yeah, that one.

> 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		

Ah, okay, so the patch fixes __next_mem_range() and thus makes
free_low_memory_core_early() to skip hotpluggable regions unlike
before.  Please explain things like that in the changelog.  Also,
what's its relationship with numa_clear_kernel_node_hotplug()?  Do we
still need them?  If so, what are the different roles that these two
separate places serve?

Thanks.

-- 
tejun

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