From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751570AbWHAEBM (ORCPT ); Tue, 1 Aug 2006 00:01:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751571AbWHAEBM (ORCPT ); Tue, 1 Aug 2006 00:01:12 -0400 Received: from smtp.osdl.org ([65.172.181.4]:50304 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751568AbWHAEBL (ORCPT ); Tue, 1 Aug 2006 00:01:11 -0400 Date: Mon, 31 Jul 2006 21:01:07 -0700 From: Andrew Morton To: Alexey Dobriyan Cc: linux-kernel@vger.kernel.org, Jay Lan Subject: Re: [PATCH] task_struct: remove writeonly counters Message-Id: <20060731210107.89cab506.akpm@osdl.org> In-Reply-To: <20060801022951.GB7006@martell.zuzino.mipt.ru> References: <20060801022951.GB7006@martell.zuzino.mipt.ru> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.17; i686-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 X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 Aug 2006 06:29:51 +0400 Alexey Dobriyan wrote: > ... > > +++ b/include/linux/sched.h > @@ -962,8 +962,6 @@ #endif > * to a stack based synchronous wait) if its doing sync IO. > */ > wait_queue_t *io_wait; > -/* i/o counters(bytes read/written, #syscalls */ > - u64 rchar, wchar, syscr, syscw; This is kinda funny. These fields were added a year and a half ago, with the intention that the info be made available to userspace. But then things got horridly stuck. It's only in the past couple of weeks that we've gained appropriate reporting-to-userspace infrastructure to be able to use these fields. And lo, on the very day when you propose removing these fields, Jay posts a new patchset ("add CSA accounting to taskstats") which finally gets around to using them. So.. we should keep these fields for now - we can perhaps remove them (in less than 1.5 years) if for some reason the CSA patches crash and burn (I don't think they will).