From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5191926A.2090608@cn.fujitsu.com> Date: Tue, 14 May 2013 09:24:58 +0800 From: Tang Chen MIME-Version: 1.0 Subject: Re: [PATCH V2 1/2] mm: hotplug: implement non-movable version of get_user_pages() called get_user_pages_non_movable() 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> <20130513091902.GP11497@suse.de> <20130513143757.GP31899@kvack.org> <20130513150147.GQ31899@kvack.org> In-Reply-To: <20130513150147.GQ31899@kvack.org> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin LaHaise , Jeff Moyer , Mel Gorman Cc: Minchan Kim , Lin Feng , akpm@linux-foundation.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, linux-mm@kvack.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Marek Szyprowski Hi Mel, Benjamin, Jeff, On 05/13/2013 11:01 PM, Benjamin LaHaise wrote: > On Mon, May 13, 2013 at 10:54:03AM -0400, Jeff Moyer wrote: >> How do you propose to move the ring pages? > > It's the same problem as doing a TLB shootdown: flush the old pages from > userspace's mapping, copy any existing data to the new pages, then > repopulate the page tables. It will likely require the addition of > address_space_operations for the mapping, but that's not too hard to do. > I think we add migrate_unpin() callback to decrease page->count if necessary, and migrate the page to a new page, and add migrate_pin() callback to pin the new page again. The migrate procedure will work just as before. We use callbacks to decrease the page->count before migration starts, and increase it when the migration is done. And migrate_pin() and migrate_unpin() callbacks will be added to struct address_space_operations. Is that right ? If so, I'll be working on it. Thanks. :) -- 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