From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 6 Mar 2008 19:53:35 -0800 (PST) From: Christoph Lameter Subject: Re: [patch 8/8] Pageflags: Eliminate PG_xxx aliases In-Reply-To: <200803071320.16967.nickpiggin@yahoo.com.au> Message-ID: References: <20080305223815.574326323@sgi.com> <200803071148.09759.nickpiggin@yahoo.com.au> <200803071320.16967.nickpiggin@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andrew Morton , ak@suse.de, Mel Gorman , apw@shadowen.org, KAMEZAWA Hiroyuki , KOSAKI Motohiro , Rik van Riel , linux-mm@kvack.org List-ID: On Fri, 7 Mar 2008, Nick Piggin wrote: > > It avoids us having to deal with aliases in the future. > > It doesn't. You still have to deal with them. Sortof. You do not have to deal with it on the level of the PG_xxx enum constant. Yes you will have to deal with the aliases at the level of the functions. > > PG_xx at this > > point is not unique which can be confusing. See the PG_reclaim in > > mm/page_alloc.c. It also means PG_readahead. If I look for > > handling of PG_readahead then I wont find it. > > You can't just pretend not to deal with aliases at that point > in mm/page_alloc.c just becuase you only have one name for the > bit position. If you only have one name for the bit position the you can localize the aliases and uses of that bit. This means you can go from a bit that you see set while debugging to the PG_xxx flag and then look for uses. Which will turn up aliases. > You still have to know that checking for PG_reclaim in bad_page > can only be done if it is *also* a bug for PG_readahead to be > found set at that point too. Because it is an alias. True. -- 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