From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbaHSPQo (ORCPT ); Tue, 19 Aug 2014 11:16:44 -0400 Received: from mga09.intel.com ([134.134.136.24]:60398 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752760AbaHSPQm (ORCPT ); Tue, 19 Aug 2014 11:16:42 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,894,1400050800"; d="scan'208";a="560606575" From: Andi Kleen To: linux-kernel@vger.kernel.org Cc: Andi Kleen , rusty@rustcorp.com.au Subject: [PATCH 1/2] params: Add a per cpu module param type Date: Tue, 19 Aug 2014 08:16:28 -0700 Message-Id: <1408461389-24163-1-git-send-email-andi@firstfloor.org> X-Mailer: git-send-email 1.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen This is mainly useful for simple statistic counters. Essentially read-only, writing only clears. Cc: rusty@rustcorp.com.au Signed-off-by: Andi Kleen --- include/linux/moduleparam.h | 4 ++++ kernel/params.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 494f99e..d019ad2 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -408,6 +408,10 @@ extern int param_set_bint(const char *val, const struct kernel_param *kp); #define param_get_bint param_get_int #define param_check_bint param_check_int +/* A per cpu read-only unsigned integer. Useful for counters. */ +extern struct kernel_param_ops param_ops_percpu_uint; +#define param_check_percpu_uint(name, p) param_check_uint + /** * module_param_array - a parameter which is an array of some type * @name: the name of the array variable diff --git a/kernel/params.c b/kernel/params.c index 34f5270..700badd 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -499,6 +499,34 @@ struct kernel_param_ops param_ops_string = { }; EXPORT_SYMBOL(param_ops_string); +/* Per CPU read only module param. */ + +static int param_percpu_uint_set(const char *val, const struct kernel_param *kp) +{ + int cpu; + + /* just clear on any write */ + for_each_possible_cpu(cpu) + *per_cpu_ptr((unsigned * __percpu)(kp->arg), cpu) = 0; + return 0; +} + +static int param_percpu_uint_get(char *buffer, const struct kernel_param *kp) +{ + int cpu; + unsigned count = 0; + + for_each_possible_cpu(cpu) + count += *per_cpu_ptr((unsigned * __percpu)(kp->arg), cpu); + return sprintf(buffer, "%u", count); +} + +struct kernel_param_ops param_ops_percpu_uint = { + .set = param_percpu_uint_set, + .get = param_percpu_uint_get, +}; +EXPORT_SYMBOL(param_ops_percpu_uint); + /* sysfs output in /sys/modules/XYZ/parameters/ */ #define to_module_attr(n) container_of(n, struct module_attribute, attr) #define to_module_kobject(n) container_of(n, struct module_kobject, kobj) -- 1.9.3