From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 18 Apr 2006 18:27:28 -0700 (PDT) From: Christoph Lameter Subject: Re: Read/Write migration entries: Implement correct behavior in copy_one_pte In-Reply-To: <20060419095044.d7333b21.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20060419095044.d7333b21.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: hugh@veritas.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@osdl.org List-ID: On Wed, 19 Apr 2006, KAMEZAWA Hiroyuki wrote: > > Note that this is again only a partial solution. mprotect() also has the > > potential of changing the write status to read. > yes. in change_pte_range(). > > Note: > fork() and mprotect() both requires mm->mmap_sem. > So both of them is not problem when migration holds mm->mmap_sem. > If we does lazy migration or memory hot removing or allows migration from > another process, this will be problem. Oh. We already allow migration from another process since the page may be mapped by multiple mm's. Page migration will then replace the ptes in *all* mm_structs that map this page with migration entries. So we need a fix here. -- 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