From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id B54576B0044 for ; Wed, 26 Dec 2012 22:11:53 -0500 (EST) Message-ID: <50DBBC40.6040700@cn.fujitsu.com> Date: Thu, 27 Dec 2012 11:10:56 +0800 From: Tang Chen MIME-Version: 1.0 Subject: Re: [PATCH v5 02/14] memory-hotplug: check whether all memory blocks are offlined or not when removing memory References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> <1356350964-13437-3-git-send-email-tangchen@cn.fujitsu.com> <50DA6AB3.2030608@jp.fujitsu.com> In-Reply-To: <50DA6AB3.2030608@jp.fujitsu.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-2022-JP Sender: owner-linux-mm@kvack.org List-ID: To: Kamezawa Hiroyuki Cc: akpm@linux-foundation.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, wujianguo@huawei.com, wency@cn.fujitsu.com, hpa@zytor.com, linfeng@cn.fujitsu.com, laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org On 12/26/2012 11:10 AM, Kamezawa Hiroyuki wrote: > (2012/12/24 21:09), Tang Chen wrote: >> From: Yasuaki Ishimatsu >> >> We remove the memory like this: >> 1. lock memory hotplug >> 2. offline a memory block >> 3. unlock memory hotplug >> 4. repeat 1-3 to offline all memory blocks >> 5. lock memory hotplug >> 6. remove memory(TODO) >> 7. unlock memory hotplug >> >> All memory blocks must be offlined before removing memory. But we don't hold >> the lock in the whole operation. So we should check whether all memory blocks >> are offlined before step6. Otherwise, kernel maybe panicked. >> >> Signed-off-by: Wen Congyang >> Signed-off-by: Yasuaki Ishimatsu > > Acked-by: KAMEZAWA Hiroyuki > > a nitpick below. > >> + >> + for (pfn = start_pfn; pfn< end_pfn; pfn += PAGES_PER_SECTION) { > > I prefer adding mem = NULL at the start of this for(). Hi Kamezawa-san, Added, thanks. :) > >> + section_nr = pfn_to_section_nr(pfn); >> + if (!present_section_nr(section_nr)) >> + continue; >> + >> + section = __nr_to_section(section_nr); >> + /* same memblock? */ >> + if (mem) >> + if ((section_nr>= mem->start_section_nr)&& >> + (section_nr<= mem->end_section_nr)) >> + continue; >> + > > Thanks, > -Kame > > > -- 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