Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754612AbYA1HuN (ORCPT ); Mon, 28 Jan 2008 02:50:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751833AbYA1Ht7 (ORCPT ); Mon, 28 Jan 2008 02:49:59 -0500 Received: from sacred.ru ([62.205.161.221]:37690 "EHLO sacred.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751825AbYA1Ht6 (ORCPT ); Mon, 28 Jan 2008 02:49:58 -0500 Message-ID: <479D88C7.5030101@openvz.org> Date: Mon, 28 Jan 2008 10:48:23 +0300 From: Pavel Emelyanov User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Andrew Morton , Vinay Sridhar CC: linux-kernel@vger.kernel.org, libc-alpha@sourceware.org, drepper@redhat.com, wli@holomorphy.com, sripathik@in.ibm.com, "Eric W. Biederman" , Pavel Emelyanov Subject: Re: [RFC] Per-thread getrusage References: <1200558425.5992.17.camel@srivinay.in.ibm.com> <20080127215242.b873c341.akpm@linux-foundation.org> In-Reply-To: <20080127215242.b873c341.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-3.0 (sacred.ru [62.205.161.221]); Mon, 28 Jan 2008 10:48:11 +0300 (MSK) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1866 Lines: 46 Andrew Morton wrote: > On Thu, 17 Jan 2008 13:57:05 +0530 Vinay Sridhar wrote: > >> Hi All, >> >> Last year, there was discussion about per-thread getrusage by adding >> RUSAGE_THREAD flag to getrusage(). Please refer to the thread >> http://lkml.org/lkml/2007/4/4/308. Ulrich had suggested that we should >> design a better user-space API. Specifically, we need a >> pthread_getrusage interface in the thread library, which accepts >> pthread_t, converts pthread_t into the corresponding tid and passes it >> down to the syscall. >> >> There are two ways to implement this in the kernel: >> 1) Introduce an additional parameter 'tid' to sys_getrusage() and put >> code in glibc to handle getrusage() and pthread_getrusage() calls >> correctly. >> 2) Introduce a new system call to handle pthread_getrusage() and leave >> sys_getrusage() untouched. >> >> We implemented the second idea above, simply because it avoids touching >> any existing code. We have implemented a new syscall, thread_getrusage() >> and we have exposed pthread_getrusage() API to applications. >> >> Could you please share your thoughts on this? Does the approach look >> alright? The code is hardly complete. It is just a prototype that works >> on IA32 at the moment. >> >> ... >> >> +asmlinkage long sys_thread_getrusage(int tid, struct rusage __user *ru); > > What happens if `tid' refers to a thread in a different pid namespace? > That's impossible. I explicitly deny namespace creation in case the CLONE_THREAD is specified. So all threads of a single process always live in one pid namespace. Thanks, Pavel -- 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/