From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wen Congyang Date: Wed, 05 Sep 2012 01:41:06 +0000 Subject: Re: [RFC v8 PATCH 08/20] memory-hotplug: remove /sys/firmware/memmap/X sysfs Message-Id: <5046ADB2.9020703@cn.fujitsu.com> List-Id: References: <1346148027-24468-1-git-send-email-wency@cn.fujitsu.com> <1346148027-24468-9-git-send-email-wency@cn.fujitsu.com> <20120831140623.8d13bd2c.akpm@linux-foundation.org> <5044454E.7070909@cn.fujitsu.com> <20120904161634.f1f9f693.akpm@linux-foundation.org> In-Reply-To: <20120904161634.f1f9f693.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: 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, 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, Christoph Lameter At 09/05/2012 07:16 AM, Andrew Morton Wrote: > On Mon, 03 Sep 2012 13:51:10 +0800 > Wen Congyang wrote: > >>>> +static void release_firmware_map_entry(struct kobject *kobj) >>>> +{ >>>> + struct firmware_map_entry *entry = to_memmap_entry(kobj); >>>> + struct page *page; >>>> + >>>> + page = virt_to_page(entry); >>>> + if (PageSlab(page) || PageCompound(page)) >>> >>> That PageCompound() test looks rather odd. Why is this done? >> >> Liu Jiang and Christoph Lameter discussed how to find slab page >> in this mail: >> https://lkml.org/lkml/2012/7/6/333. > > Well, please add a code comment to release_firmware_map_entry() which > fully explains these things. > > I see that Christoph and I agree: "It would be cleaner if memory > hotplug had an indicator which allocation mechanism was used and would > use the corresponding free action". You didn't respond to this > suggestion when he made it, nor when I made it. What are your thoughts > on this? Hmm, I think it is better to use an indicator which allocation mechanism was used. I will do it in the next version. Thanks Wen Congyang