From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 24 May 2006 21:37:00 +0100 (BST) From: Hugh Dickins Subject: Re: Allow migration of mlocked pages In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: akpm@osdl.org, linux-mm@kvack.org, KAMEZAWA Hiroyuki List-ID: On Wed, 24 May 2006, Christoph Lameter wrote: > On Wed, 24 May 2006, Hugh Dickins wrote: > > > Oh, I'm not worried about whether ordinary VM_LOCKED pages will get > > migrated properly, I can't see any problem with that. It's whether > > something somewhere is using mlock and somehow relying on the > > physical pages to be pinned. I don't know what form that "somehow" > > would take, and I'm not saying there is or can be any such thing: > > just worried that we want wide exposure yet few testers migrate. > > All of these driver mappings are installed using remap_pfn_page. These are > mappings that are not considered by page migration at all because: Misunderstanding again. I've no worries about those drivers you've supplied a patch for, what you've done there is surely okay. I'm (slightly) worried there's some app out there that's been using mlock to pin physical pages. My worry may be senseless: how can physical pages mean anything to it without a driver in the kernel to cooperate in the assumption? If it were a big worry, I wouldn't have sent you in this "migrate VM_LOCKED" direction at all. I'm all for it, just cautioning that we want a period of exposure to varied testing. Hugh -- 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