From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755971AbYAOJFU (ORCPT ); Tue, 15 Jan 2008 04:05:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752292AbYAOJFB (ORCPT ); Tue, 15 Jan 2008 04:05:01 -0500 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:46586 "EHLO ecfrec.frec.bull.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750744AbYAOJE6 (ORCPT ); Tue, 15 Jan 2008 04:04:58 -0500 Message-ID: <478C76D4.3010700@bull.net> Date: Tue, 15 Jan 2008 10:03:16 +0100 From: Nadia Derbey Organization: BULL/DT/OSwR&D/Linux User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040115 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Yasunori Goto Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, matthltc@us.ibm.com Subject: Re: [RFC PATCH 4/4] [RESEND] Recomputing msgmni on memory add / remove References: <20080114155402.690906000@bull.net> <20080114155602.855698000@bull.net> <20080115164440.6DBB.Y-GOTO@jp.fujitsu.com> In-Reply-To: <20080115164440.6DBB.Y-GOTO@jp.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 15/01/2008 10:13:18, Serialize by Router on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 15/01/2008 10:13:19, Serialize complete at 15/01/2008 10:13:19 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yasunori Goto wrote: > Hello Nadia-san. > > >>@@ -118,6 +122,10 @@ struct ipc_namespace { >> size_t shm_ctlall; >> int shm_ctlmni; >> int shm_tot; >>+ >>+#ifdef CONFIG_MEMORY_HOTPLUG >>+ struct notifier_block ipc_memory_hotplug; >>+#endif >> }; > > > I'm sorry, but I don't see why each ipc namespace must have each callbacks > of memory hotplug. > I prefer only one callback for each subsystem, not for each namespace. > In addition, the recompute_msgmni() calculation looks very similar for > all ipc namespace. > Or do you wish each ipc namespace have different callback for the future? > Actually, this is what I wanted to do at the very beginning: have a single callback that would recompute the msgmni for each ipc namespace. But the issue here is that the namespaces are not linked to each other, so I had no simple way to go through all the namespaces. I solved the issue by having a callback for any single ipc namespace and make it recompute the msgmni value for itslef. > > > BTW, have you ever tested this patch? If you don't have any test environment > for memory hotplug code, then I'll check it. :-) Well, I tested it but not in "real configuration": what I did is that I changed the status by hand under sysfs to offline. I also changed remove_memory() in mm/memory_hotplug.c in the following way (instead of returninf EINVAL): 1) decrease the total_ram pages 2) call memory_notify(MEM_OFFLINE, NULL) and checked that the msgmni was recomputed. But sure, if you are candidate to test it, that would be great! Regards, Nadia