From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 4 Apr 2007 13:56:18 -0700 From: Andrew Morton Subject: Re: missing madvise functionality Message-Id: <20070404135618.d39f98f4.akpm@linux-foundation.org> In-Reply-To: <4613E9AF.3030802@redhat.com> References: <46128051.9000609@redhat.com> <46128CC2.9090809@redhat.com> <20070403172841.GB23689@one.firstfloor.org> <20070403125903.3e8577f4.akpm@linux-foundation.org> <4612B645.7030902@redhat.com> <20070403202937.GE355@devserv.devel.redhat.com> <20070403144948.fe8eede6.akpm@linux-foundation.org> <20070403160231.33aa862d.akpm@linux-foundation.org> <20070404110406.c79b850d.akpm@linux-foundation.org> <4613E9AF.3030802@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Hugh Dickins , Jakub Jelinek , Ulrich Drepper , Andi Kleen , Linux Kernel , linux-mm@kvack.org List-ID: On Wed, 04 Apr 2007 14:08:47 -0400 Rik van Riel wrote: > Andrew Morton wrote: > > > There are other ways of doing it - I guess we could use a new page flag to > > indicate that this is one-of-those-pages, and add new code to handle it in > > all the right places. > > That's what I did. I'm currently working on the > zap_page_range() side of things. Let's try to avoid consuming another page flag if poss, please. Perhaps use PAGE_MAPPING_ANON's neighbouring bit? > > One thing which we haven't sorted out with all this stuff: once the > > application has marked an address range (and some pages) as > > whatever-were-going-call-this-feature, how does the application undo that > > change? > > It doesn't have to do anything. Just access the page and the > MMU will mark it dirty/accessed and the VM will not reclaim > it. um, OK. I suspect it would be good to clear the page's PageWhateverWereGoingToCallThisThing() state when this happens. Otherwise when the page gets clean again (ie: added to swapcache then written out) then it will look awfully similar to one of these new types of pages and things might get confusing. We'll see. -- 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