Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758121Ab3G3I0W (ORCPT ); Tue, 30 Jul 2013 04:26:22 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37646 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753500Ab3G3I0V (ORCPT ); Tue, 30 Jul 2013 04:26:21 -0400 Date: Tue, 30 Jul 2013 01:25:44 -0700 From: Andrew Morton To: Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, kosaki.motohiro@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, bp@suse.de, Dave Hansen Subject: Re: [PATCH resend] drop_caches: add some documentation and info message Message-Id: <20130730012544.2f33ebf6.akpm@linux-foundation.org> In-Reply-To: <20130730074531.GA10584@dhcp22.suse.cz> References: <1374842669-22844-1-git-send-email-mhocko@suse.cz> <20130729135743.c04224fb5d8e64b2730d8263@linux-foundation.org> <20130730074531.GA10584@dhcp22.suse.cz> X-Mailer: Sylpheed 2.7.1 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1407 Lines: 38 On Tue, 30 Jul 2013 09:45:31 +0200 Michal Hocko wrote: > On Mon 29-07-13 13:57:43, Andrew Morton wrote: > > On Fri, 26 Jul 2013 14:44:29 +0200 Michal Hocko 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? > > I am OK with that but can we use a top bit instead. Maybe we never have > other entities to drop in the future but it would be better to have a room for them > just in case. If we add another flag in the future it can use bit 3? > So what about using 1<<31 instead? Could, but negative (or is it positive?) numbers are a bit of a pain. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/