From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 29 Nov 2012 16:04:43 -0800 From: Zach Brown Subject: Re: [BUG REPORT] [mm-hotplug, aio] aio ring_pages can't be offlined Message-ID: <20121130000443.GK18574@lenny.home.zabbo.net> References: <1354172098-5691-1-git-send-email-linfeng@cn.fujitsu.com> <20121129153930.477e9709.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121129153930.477e9709.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Lin Feng , viro@zeniv.linux.org.uk, bcrl@kvack.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, hughd@google.com, cl@linux.com, mgorman@suse.de, minchan@kernel.org, isimatu.yasuaki@jp.fujitsu.com, laijs@cn.fujitsu.com, wency@cn.fujitsu.com, tangchen@cn.fujitsu.com, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org > The best I can think of is to make changes in or around > get_user_pages(), to steal the pages from userspace and replace them > with non-movable ones before pinning them. The performance cost of > something like this would surely be unacceptable for direct-io, but > maybe OK for the aio ring and futexes. In the aio case it seems like it could be taught to populate the mapping with non-movable pages to begin with. It's calling get_user_pages() a few lines after instantiating the mapping itself with do_mmap_pgoff(). - z -- 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