From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx193.postini.com [74.125.245.193]) by kanga.kvack.org (Postfix) with SMTP id D128E6B004D for ; Mon, 23 Jul 2012 21:11:23 -0400 (EDT) Date: Tue, 24 Jul 2012 10:11:43 +0900 From: Minchan Kim Subject: Re: + memory-hotplug-fix-kswapd-looping-forever-problem-fix-fix.patch added to -mm tree Message-ID: <20120724011143.GA13155@bbox> References: <20120718143810.b15564b3.akpm@linux-foundation.org> <20120719001002.GA6579@bbox> <20120719002102.GN24336@google.com> <20120719004845.GA7346@bbox> <20120719165750.GP24336@google.com> <20120719235057.GA21012@bbox> <20120720142213.f4a4a68e.akpm@linux-foundation.org> <20120720213641.GA6823@google.com> <20120723045855.GC6832@bbox> <20120723154247.GE6823@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120723154247.GE6823@google.com> Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Andrew Morton , Ralf Baechle , aaditya.kumar.30@gmail.com, kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org, Johannes Weiner , Yinghai Lu On Mon, Jul 23, 2012 at 08:42:47AM -0700, Tejun Heo wrote: > Hello, Minchan. > > On Mon, Jul 23, 2012 at 01:58:55PM +0900, Minchan Kim wrote: > > I would like to know what fields you are concerning because most of field > > The above question itself is a problem. It's subtle to hell. Some > fields of this data structure is used during early boot but at some > point all are reset to zero, so we have to be careful about how those > fields are used before and after. > > This might seem clear now but things like this are likely to make > people later working on the code go WTF. Let's say for whatever > reason ->bdata needs to be accessed after free_area_init - e.g. > arch_add_memory() needs some info from bdata, what then? > > What if we end up having to add a new property field which is > determined by platform code but used by generic code. I would add a > field to pgdat, init it from numa.c and then later use it in generic > code. If the field gets zeroed inbetween, I would get pretty annoyed. > > I really don't think this subject is worth the amount of discussion we > had in this thread. Just make the archs clear the data structure on > creation. Anything else is silly. I sent patchset and will wait of akpm's opinion. Thanks for the comment, Tejun. -- Kind regards, Minchan Kim -- 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