From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5194748A.5070700@cn.fujitsu.com> Date: Thu, 16 May 2013 13:54:18 +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> <5191B5B3.7080406@cn.fujitsu.com> <20130515132453.GB11497@suse.de> In-Reply-To: <20130515132453.GB11497@suse.de> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-15; format=flowed Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman 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 Hi Mel, On 05/15/2013 09:24 PM, Mel Gorman wrote: > If it is to be an address space operations sturcture then you'll need a > pseudo mapping structure for anonymous pages that are pinned by aio -- > similar in principal to how swapper_space is used for managing PageSwapCache > or how anon_vma structures can be associated with a page. > > However, I warn you that you may find that the address_space is the > wrong level to register such callbacks, it just seemed like the obvious > first choice. A potential alternative implementation is to create a 1:1 > association between pages and a long-lived holder that is stored on a hash > table (similar style of arrangement as page_waitqueue). A page is looked up > in the hash table and if an entry exists, it points to an callback structure > to the subsystem holding the pin. It's up to the subsystem to register the > callbacks when it is about to pin a page (get_user_pages_longlived(...., > &release_ops) and figure out how to release the pin safely. > OK, I'll try to figure out a proper place to put the callbacks. But I think we need to add something new to struct page. I'm just not sure if it is OK. Maybe we can discuss more about it when I send a RFC patch. Thanks for the advices, and I'll try them. 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