From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx173.postini.com [74.125.245.173]) by kanga.kvack.org (Postfix) with SMTP id 47EC56B002B for ; Wed, 17 Oct 2012 05:03:20 -0400 (EDT) Message-ID: <507E75AA.2000605@cn.fujitsu.com> Date: Wed, 17 Oct 2012 17:08:58 +0800 From: Wen Congyang MIME-Version: 1.0 Subject: Re: [PATCH 1/4] acpi,memory-hotplug : add memory offline code to acpi_memory_device_remove() References: <506C0AE8.40702@jp.fujitsu.com> <506C0C53.60205@jp.fujitsu.com> <50727984.20401@cn.fujitsu.com> <507E54AA.2080806@cn.fujitsu.com> In-Reply-To: Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Yasuaki Ishimatsu , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, cl@linux.com, minchan.kim@gmail.com, akpm@linux-foundation.org At 10/17/2012 04:59 PM, KOSAKI Motohiro Wrote: > On Wed, Oct 17, 2012 at 2:48 AM, Wen Congyang wrote: >> At 10/13/2012 03:10 AM, KOSAKI Motohiro Wrote: >>>>>> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) >>>>>> +static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device) >>>>>> { >>>>>> int result; >>>>>> struct acpi_memory_info *info, *n; >>>>>> >>>>>> + list_for_each_entry_safe(info, n, &mem_device->res_list, list) { >>>>> >>>>> Which lock protect this loop? >>>> >>>> There is no any lock to protect it now... >>> >>> When iterate an item removal list, you should use lock for protecting from >>> memory corruption. >>> >>> >>> >>> >>>>>> +static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) >>>>>> +{ >>>>>> + int result; >>>>>> >>>>>> /* >>>>>> * Ask the VM to offline this memory range. >>>>>> * Note: Assume that this function returns zero on success >>>>>> */ >>>>> >>>>> Write function comment instead of this silly comment. >>>>> >>>>>> - list_for_each_entry_safe(info, n, &mem_device->res_list, list) { >>>>>> - if (info->enabled) { >>>>>> - result = remove_memory(info->start_addr, info->length); >>>>>> - if (result) >>>>>> - return result; >>>>>> - } >>>>>> - kfree(info); >>>>>> - } >>>>>> + result = acpi_memory_remove_memory(mem_device); >>>>>> + if (result) >>>>>> + return result; >>>>>> >>>>>> /* Power-off and eject the device */ >>>>>> result = acpi_memory_powerdown_device(mem_device); >>>>> >>>>> This patch move acpi_memory_powerdown_device() from ACPI_NOTIFY_EJECT_REQUEST >>>>> to release callback, but don't explain why. >>>> >>>> Hmm, it doesn't move the code. It just reuse the code in acpi_memory_powerdown_device(). >>> >>> Even if reuse or not reuse, you changed the behavior. If any changes >>> has no good rational, you cannot get an ack. >> >> I don't understand this? IIRC, the behavior isn't changed. > > Heh, please explain why do you think so. > We just introduce a function, and move codes from acpi_memory_disable_device() to the new function. We call the new function in acpi_memory_disable_device(), so the function acpi_memory_disable_device()'s behavior isn't changed. Maybe I don't understand what do you want to say. Thanks Wen Congyang -- 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