From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <45F67D9A.8020202@yahoo.com.au> Date: Tue, 13 Mar 2007 21:31:54 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [RFC][PATCH 2/3] swsusp: Do not use page flags References: <200703131016.12935.rjw@sisk.pl> <45F66D9B.7000301@yahoo.com.au> <200703131117.43818.rjw@sisk.pl> In-Reply-To: <200703131117.43818.rjw@sisk.pl> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "Rafael J. Wysocki" Cc: Pavel Machek , Christoph Lameter , linux-mm@kvack.org, pm list , Johannes Berg , Peter Zijlstra List-ID: Rafael J. Wysocki wrote: > On Tuesday, 13 March 2007 10:23, Nick Piggin wrote: > >>I wouldn't say that. You're creating an interface here that is going to be >>used outside swsusp. Users of that interface may not need locking now, but >>that could cause problems down the line. > > > I think we can add the locking when it's necessary. For now, IMHO, it could be > confusing to someone who doesn't know the locking is not needed. I don't know why it would confuse them. We just define the API to guarantee the correct locking, and that means the locking _is_ needed. You don't have to care what the callers are doing. That's the beauty of a sane API. >>Sure you don't _need_ an rbtree, but our implementation makes it so simple >>that there isn't much downside. > > > Not much, but the code is more complicated. But it's in its own file and has a contained API, so it is very easy to review, test and verify. >>>mark_nosave_pages() refers to a function that's invisible outside snapshot.c >>>and I didn't think it was a good idea to separate mark_nosave_pages() >>>from register_nosave_region(). >> >>But that's because you even use mark_nosave_pages in your implementation. >>Mine uses the nosave regions directly. > > > Well, I think we need two bits per page anyway, to mark free pages and > pages allocated by swsusp, so using the nosave regions directly won't save us > much. Well I think it is a cleaner though. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com -- 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