From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Tue, 04 Sep 2012 23:16:34 +0000 Subject: Re: [RFC v8 PATCH 08/20] memory-hotplug: remove /sys/firmware/memmap/X sysfs Message-Id: <20120904161634.f1f9f693.akpm@linux-foundation.org> 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> In-Reply-To: <5044454E.7070909@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Wen Congyang 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 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?