Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753373AbYKMMWe (ORCPT ); Thu, 13 Nov 2008 07:22:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751902AbYKMMWZ (ORCPT ); Thu, 13 Nov 2008 07:22:25 -0500 Received: from ns1.suse.de ([195.135.220.2]:49716 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751635AbYKMMWY (ORCPT ); Thu, 13 Nov 2008 07:22:24 -0500 From: Nikanth Karthikesan Organization: suse.de To: Andrew Morton Subject: [PATCH] Make /proc/sys/vm/drop_caches write only Date: Thu, 13 Nov 2008 17:54:11 +0530 User-Agent: KMail/1.9.51 (KDE/4.0.4; ; ) Cc: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200811131754.11863.knikanth@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1460 Lines: 47 /proc/sys/vm/drop_caches is used only to trigger dropping caches. It does not disable the cache. The ability to read the value written to this file long back gives wrong impression. Signed-off-by: Nikanth Karthikesan --- diff --git a/fs/drop_caches.c b/fs/drop_caches.c index 3e5637f..9892e1b 100644 --- a/fs/drop_caches.c +++ b/fs/drop_caches.c @@ -66,11 +66,9 @@ int drop_caches_sysctl_handler(ctl_table *table, int write, struct file *file, void __user *buffer, size_t *length, loff_t *ppos) { proc_dointvec_minmax(table, write, file, buffer, length, ppos); - if (write) { - if (sysctl_drop_caches & 1) - drop_pagecache(); - if (sysctl_drop_caches & 2) - drop_slab(); - } + if (sysctl_drop_caches & 1) + drop_pagecache(); + if (sysctl_drop_caches & 2) + drop_slab(); return 0; } diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 9d048fa..dff3c13 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1015,7 +1015,7 @@ static struct ctl_table vm_table[] = { .procname = "drop_caches", .data = &sysctl_drop_caches, .maxlen = sizeof(int), - .mode = 0644, + .mode = 0200, .proc_handler = drop_caches_sysctl_handler, .strategy = &sysctl_intvec, }, -- 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/