From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx145.postini.com [74.125.245.145]) by kanga.kvack.org (Postfix) with SMTP id 5EDAF6B0031 for ; Wed, 31 Jul 2013 23:17:58 -0400 (EDT) Date: Wed, 31 Jul 2013 20:17:08 -0700 From: Andrew Morton Subject: Re: [PATCH resend] drop_caches: add some documentation and info message Message-Id: <20130731201708.efa5ae87.akpm@linux-foundation.org> In-Reply-To: <51F9D1F6.4080001@jp.fujitsu.com> References: <1374842669-22844-1-git-send-email-mhocko@suse.cz> <20130729135743.c04224fb5d8e64b2730d8263@linux-foundation.org> <51F9D1F6.4080001@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, kamezawa.hiroyu@jp.fujitsu.com, bp@suse.de, dave@linux.vnet.ibm.com On Wed, 31 Jul 2013 23:11:50 -0400 KOSAKI Motohiro wrote: > >> --- a/fs/drop_caches.c > >> +++ b/fs/drop_caches.c > >> @@ -59,6 +59,8 @@ int drop_caches_sysctl_handler(ctl_table *table, int write, > >> if (ret) > >> return ret; > >> if (write) { > >> + printk(KERN_INFO "%s (%d): dropped kernel caches: %d\n", > >> + current->comm, task_pid_nr(current), sysctl_drop_caches); > >> if (sysctl_drop_caches & 1) > >> iterate_supers(drop_pagecache_sb, NULL); > >> if (sysctl_drop_caches & 2) > > > > How about we do > > > > if (!(sysctl_drop_caches & 4)) > > printk(....) > > > > so people can turn it off if it's causing problems? > > The best interface depends on the purpose. If you want to detect crazy application, > we can't assume an application co-operate us. So, I doubt this works. You missed the "!". I'm proposing that setting the new bit 2 will permit people to prevent the new printk if it is causing them problems. -- 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