Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932166AbaAITa7 (ORCPT ); Thu, 9 Jan 2014 14:30:59 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:51772 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755498AbaAITav (ORCPT ); Thu, 9 Jan 2014 14:30:51 -0500 Date: Thu, 9 Jan 2014 11:31:21 -0800 From: Greg Kroah-Hartman To: Sudeep Holla Cc: "x86@kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Ashok Raj , Benjamin Herrenschmidt , Rob Herring Subject: Re: [PATCH RFC 1/3] drivers: base: support cpu cache information interface to userspace via sysfs Message-ID: <20140109193121.GA14991@kroah.com> References: <1389209168-17189-1-git-send-email-sudeep.holla@arm.com> <1389209168-17189-2-git-send-email-sudeep.holla@arm.com> <20140108202707.GE8417@kroah.com> <52CEF624.9020702@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52CEF624.9020702@arm.com> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 09, 2014 at 07:19:00PM +0000, Sudeep Holla wrote: > On 08/01/14 20:27, Greg Kroah-Hartman wrote: > > On Wed, Jan 08, 2014 at 07:26:06PM +0000, Sudeep Holla wrote: > >> From: Sudeep Holla > >> > >> This patch adds initial support for providing processor cache information > >> to userspace through sysfs interface. This is based on x86 implementation > >> and hence the interface is intended to be fully compatible. > >> > >> A per-cpu array of cache information maintained is used mainly for > >> sysfs-related book keeping. > >> > >> Signed-off-by: Sudeep Holla > >> --- > >> drivers/base/Makefile | 2 +- > >> drivers/base/cacheinfo.c | 296 ++++++++++++++++++++++++++++++++++++++++++++++ > >> include/linux/cacheinfo.h | 43 +++++++ > >> 3 files changed, 340 insertions(+), 1 deletion(-) > >> create mode 100644 drivers/base/cacheinfo.c > >> create mode 100644 include/linux/cacheinfo.h > >> > >> diff --git a/drivers/base/Makefile b/drivers/base/Makefile > >> index 94e8a80..76f07c8 100644 > >> --- a/drivers/base/Makefile > >> +++ b/drivers/base/Makefile > >> @@ -4,7 +4,7 @@ obj-y := core.o bus.o dd.o syscore.o \ > >> driver.o class.o platform.o \ > >> cpu.o firmware.o init.o map.o devres.o \ > >> attribute_container.o transport_class.o \ > >> - topology.o > >> + topology.o cacheinfo.o > >> obj-$(CONFIG_DEVTMPFS) += devtmpfs.o > >> obj-$(CONFIG_DMA_CMA) += dma-contiguous.o > >> obj-y += power/ > >> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c > >> new file mode 100644 > >> index 0000000..f436c31 > >> --- /dev/null > >> +++ b/drivers/base/cacheinfo.c > >> @@ -0,0 +1,296 @@ > >> +/* > >> + * cacheinfo support - processor cache information via sysfs > >> + * > >> + * Copyright (C) 2013 ARM Ltd. > >> + * All Rights Reserved > >> + * > >> + * Author: Sudeep Holla > >> + * > >> + * This program is free software; you can redistribute it and/or modify > >> + * it under the terms of the GNU General Public License version 2 as > >> + * published by the Free Software Foundation. > >> + * > >> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > >> + * kind, whether express or implied; without even the implied warranty > >> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > >> + * GNU General Public License for more details. > >> + */ > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> +#include > >> + > >> +struct cache_attr { > >> + struct attribute attr; > >> + ssize_t(*show) (unsigned int, unsigned short, char *); > >> + ssize_t(*store) (unsigned int, unsigned short, const char *, size_t); > >> +}; > >> + > >> +/* pointer to kobject for cpuX/cache */ > >> +static DEFINE_PER_CPU(struct kobject *, ci_cache_kobject); > >> +#define per_cpu_cache_kobject(cpu) (per_cpu(ci_cache_kobject, cpu)) > >> + > >> +struct index_kobject { > >> + struct kobject kobj; > >> + unsigned int cpu; > >> + unsigned short index; > >> +}; > >> + > >> +static cpumask_t cache_dev_map; > >> + > >> +/* pointer to array of kobjects for cpuX/cache/indexY */ > > > > Please don't use "raw" kobjects for this, use the device attribute > > groups, that's what they are there for. Bonus is that your code should > > get a lot simpler when you do that. > > > > Yes I now understand device attribute group simplifies the code, but I think > kobjects are still needed as we need to track both cpu and cache index. > By reusing only cpu device kobject, we can track cpu only. I don't understand, you are putting things under the cpu device object, why do you care about a "cache" kobject? > One thought I have is to make cache_info structure common to all architecture > (for now its ARM specific) and introduce kobject in that similar to ia64 > implementation. That even eliminates lot of weak functions defined. Please don't use raw kobjects if at all possible, it's not good for a variety of reasons (no userspace events, have to roll your own code, etc.) thanks, greg k-h -- 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/