From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 282546B004A for ; Mon, 20 Sep 2010 21:05:24 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o8L15Kcs022867 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Tue, 21 Sep 2010 10:05:20 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3D03745DE51 for ; Tue, 21 Sep 2010 10:05:20 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id C0C6A1EF0A1 for ; Tue, 21 Sep 2010 10:05:19 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 6B784E08007 for ; Tue, 21 Sep 2010 10:05:19 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 11D6EE08001 for ; Tue, 21 Sep 2010 10:05:16 +0900 (JST) Date: Tue, 21 Sep 2010 10:00:11 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFCv2][PATCH] add some drop_caches documentation and info messsge Message-Id: <20100921100011.86f270de.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100916165047.DAD42998@kernel.beaverton.ibm.com> References: <20100916165047.DAD42998@kernel.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, lnxninja@linux.vnet.ibm.com, ebiederm@xmission.com, kosaki.motohiro@jp.fujitsu.com List-ID: On Thu, 16 Sep 2010 09:50:47 -0700 Dave Hansen wrote: > > This version tones down the BUG_ON(). I also noticed that the > documentation fails to mention that more than just the inode > and dentry slabs are shrunk. > > -- > > There is plenty of anecdotal evidence and a load of blog posts > suggesting that using "drop_caches" periodically keeps your system > running in "tip top shape". Perhaps adding some kernel > documentation will increase the amount of accurate data on its use. > > If we are not shrinking caches effectively, then we have real bugs. > Using drop_caches will simply mask the bugs and make them harder > to find, but certainly does not fix them, nor is it an appropriate > "workaround" to limit the size of the caches. > > It's a great debugging tool, and is really handy for doing things > like repeatable benchmark runs. So, add a bit more documentation > about it, and add a little KERN_NOTICE. It should help developers > who are chasing down reclaim-related bugs. > > Signed-off-by: Dave Hansen Reviewed-by: KAMEZAWA Hiroyuki thanks. -- 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