Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751897AbaBGUbc (ORCPT ); Fri, 7 Feb 2014 15:31:32 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:58944 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751511AbaBGUbb (ORCPT ); Fri, 7 Feb 2014 15:31:31 -0500 Date: Fri, 7 Feb 2014 12:31:29 -0800 From: Andrew Morton To: Johannes Weiner Cc: Rik van Riel , Dave Hansen , Michal Hocko , KOSAKI Motohiro , KAMEZAWA Hiroyuki , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch] drop_caches: add some documentation and info message Message-Id: <20140207123129.84f9fb0aaf32f0e09c78851a@linux-foundation.org> In-Reply-To: <20140207181332.GG6963@cmpxchg.org> References: <1391794851-11412-1-git-send-email-hannes@cmpxchg.org> <52F51E19.9000406@redhat.com> <20140207181332.GG6963@cmpxchg.org> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-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 On Fri, 7 Feb 2014 13:13:32 -0500 Johannes Weiner wrote: > @@ -63,6 +64,9 @@ int drop_caches_sysctl_handler(ctl_table *table, int write, > iterate_supers(drop_pagecache_sb, NULL); > if (sysctl_drop_caches & 2) > drop_slab(); > + printk_ratelimited(KERN_INFO "%s (%d): dropped kernel caches: %d\n", > + current->comm, task_pid_nr(current), > + sysctl_drop_caches); > } > return 0; > } My concern with this is that there may be people whose other-party-provided software uses drop_caches. Their machines will now sit there emitting log messages and there's nothing they can do about it, apart from whining at their vendors. We could do something like this? --- a/fs/drop_caches.c~drop_caches-add-some-documentation-and-info-message-fix +++ a/fs/drop_caches.c @@ -60,13 +60,17 @@ int drop_caches_sysctl_handler(ctl_table if (ret) return ret; if (write) { + static int stfu; + if (sysctl_drop_caches & 1) iterate_supers(drop_pagecache_sb, NULL); if (sysctl_drop_caches & 2) drop_slab(); - printk_ratelimited(KERN_INFO "%s (%d): dropped kernel caches: %d\n", - current->comm, task_pid_nr(current), - sysctl_drop_caches); + stfu |= sysctl_drop_caches & 4; + if (!stfu) + pr_info_ratelimited("%s (%d): dropped kernel caches: %d\n", + current->comm, task_pid_nr(current), + sysctl_drop_caches); } return 0; } _ (note switch to pr_info_ratelimited) -- 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/