From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 18 Mar 2008 21:15:05 +0900 (JST) Message-Id: <20080318.211505.93059628.taka@valinux.co.jp> Subject: Re: [PATCH 2/4] Block I/O tracking From: Hirokazu Takahashi In-Reply-To: <20080318205501.59877972.kamezawa.hiroyu@jp.fujitsu.com> References: <20080318192233.89c5cc3e.kamezawa.hiroyu@jp.fujitsu.com> <20080318.203422.45236787.taka@valinux.co.jp> <20080318205501.59877972.kamezawa.hiroyu@jp.fujitsu.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: kamezawa.hiroyu@jp.fujitsu.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org List-ID: Hi, > > > And, blist seems to be just used for force_empty. > > > Do you really need this ? no alternative ? > > > > I selected this approach because it was the simplest way for the > > first implementation. > > > > I've been also thinking about what you pointed. > > If you don't mind taking a long time to remove a bio cgroup, it will be > > the easiest way that you can scan all pages to find the pages which > > belong to the cgroup and delete them. It may be enough since you may > > say it will rarely happen. But it might cause some trouble on machines > > with huge memory. > > > Hmm, force_empty itself is necessary ? It is called when bio cgroups are removed. With the current implementation, when you delete a bio cgroup, the bio_cgroup members of page_cgroups which point the cgroup have to be cleared. So I'm looking for another way like: - Use some kind of id instead of a pointer to a bio cgroup, so you can check whether the id is valid before you use it. - Don't free the bio cgroup until all the pages referring to the cgroup. I also want to implement that if you find a page whose cgroup is already removed, the page should be assigned to a new cgroup. Thank you, Hirokazu Takahashi. -- 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