From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [RFC][PATCH 2/3] swsusp: Do not use page flags Date: Tue, 13 Mar 2007 21:31:54 +1100 Message-ID: <45F67D9A.8020202@yahoo.com.au> References: <200703131016.12935.rjw@sisk.pl> <45F66D9B.7000301@yahoo.com.au> <200703131117.43818.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <200703131117.43818.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.osdl.org Errors-To: linux-pm-bounces@lists.osdl.org To: "Rafael J. Wysocki" Cc: linux-mm@kvack.org, Peter Zijlstra , Pavel Machek , pm list , Johannes Berg , Christoph Lameter List-Id: linux-pm@vger.kernel.org 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 co= uld 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 snapsh= ot.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 sav= e 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 =