From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 14 Jun 2007 07:19:19 -0700 (PDT) From: Christoph Lameter Subject: Re: [RFC] memory unplug v5 [1/6] migration by kernel In-Reply-To: <20070614172936.12b94ad7.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20070614155630.04f8170c.kamezawa.hiroyu@jp.fujitsu.com> <20070614155929.2be37edb.kamezawa.hiroyu@jp.fujitsu.com> <20070614161146.5415f493.kamezawa.hiroyu@jp.fujitsu.com> <20070614164128.42882f74.kamezawa.hiroyu@jp.fujitsu.com> <20070614172936.12b94ad7.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: linux-mm@kvack.org, mel@csn.ul.ie, y-goto@jp.fujitsu.com, hugh@veritas.com List-ID: On Thu, 14 Jun 2007, KAMEZAWA Hiroyuki wrote: > But...during discussion with you, I found anon_vma is now freed by RCU... > > Ugh, then, what I have to do is rcu_read_lock() -> rcu_read_unlock() while > migrating anon ptes. If we can rcu read lock here, we don't need dummy_vma. > How about this ? Hmmmm... Looks good. Maybe take the RCU lock unconditionally? Is there a problem if we do so? Then the patch becomes very small and it looks cleaner. Is there an issue with calling try_to_unmap for an unmapped page? We check in try_to_unmap if the pte is valid. If it was unmapped then try_to_unmap will fail anyways. -- 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