From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mel Gorman Subject: Re: [PATCH V2 1/2] mm: hotplug: implement non-movable version of get_user_pages() called get_user_pages_non_movable() Date: Mon, 13 May 2013 10:19:02 +0100 Message-ID: <20130513091902.GP11497@suse.de> References: <1360056113-14294-1-git-send-email-linfeng@cn.fujitsu.com> <1360056113-14294-2-git-send-email-linfeng@cn.fujitsu.com> <20130205120137.GG21389@suse.de> <20130206004234.GD11197@blaptop> <20130206095617.GN21389@suse.de> <5190AE4F.4000103@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: Minchan Kim , Lin Feng , akpm@linux-foundation.org, bcrl@kvack.org, viro@zeniv.linux.org.uk, khlebnikov@openvz.org, walken@google.com, kamezawa.hiroyu@jp.fujitsu.com, riel@redhat.com, rientjes@google.com, isimatu.yasuaki@jp.fujitsu.com, wency@cn.fujitsu.com, laijs@cn.fujitsu.com, jiang.liu@huawei.com, zab@redhat.com, jmoyer@redhat.com, linux-mm@kvack.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Marek Szyprowski To: Tang Chen Return-path: Content-Disposition: inline In-Reply-To: <5190AE4F.4000103@cn.fujitsu.com> Sender: owner-linux-aio@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Mon, May 13, 2013 at 05:11:43PM +0800, Tang Chen wrote: > Hi Mel, > > On 02/06/2013 05:56 PM, Mel Gorman wrote: > > > >There is the possibility that callbacks could be introduced for > >migrate_unpin() and migrate_pin() that takes a list of PFN pairs > >(old,new). The unpin callback should release the old PFNs and barrier > >against any operations until the migrate_pfn() callback is called with > >the updated pfns to be repinned. Again it would fully depend on subsystems > >implementing it properly. > > > >The callback interface would be more robust but puts a lot more work on > >the driver side where your milage will vary. > > > > I'm very interested in the "callback" way you said. > > For memory hot-remove case, the aio pages are pined in memory and making > the pages cannot be offlined, furthermore, the pages cannot be removed. > > IIUC, you mean implement migrate_unpin() and migrate_pin() callbacks in aio > subsystem, and call them when hot-remove code tries to offline > pages, right ? > > If so, I'm wondering where should we put this callback pointers ? > In struct page ? > No, I would expect the callbacks to be part the address space operations which can be found via page->mapping. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: aart@kvack.org