Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946017AbbEWULf (ORCPT ); Sat, 23 May 2015 16:11:35 -0400 Received: from mail-ig0-f178.google.com ([209.85.213.178]:38534 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932397AbbEWULe (ORCPT ); Sat, 23 May 2015 16:11:34 -0400 MIME-Version: 1.0 In-Reply-To: <1432219487-13364-1-git-send-email-mathieu.desnoyers@efficios.com> References: <1432219487-13364-1-git-send-email-mathieu.desnoyers@efficios.com> Date: Sat, 23 May 2015 13:11:33 -0700 X-Google-Sender-Auth: eNoQO1qqBR3RTWikQNljxFhCsEo Message-ID: Subject: Re: [RFC PATCH] percpu system call: fast userspace percpu critical sections From: Linus Torvalds To: Mathieu Desnoyers Cc: Paul Turner , Andrew Hunter , Ben Maurer , Linux Kernel Mailing List , Peter Zijlstra , Ingo Molnar , Steven Rostedt , "Paul E. McKenney" , Josh Triplett , Lai Jiangshan , Andrew Morton Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 802 Lines: 22 On Thu, May 21, 2015 at 7:44 AM, Mathieu Desnoyers wrote: > Expose a new system call allowing userspace threads to register > a TLS area used as an ABI between the kernel and userspace to > share information required to create efficient per-cpu critical > sections in user-space. Not a way in hell. You do user accesses from preempt notifiers. That's so ludicrously broken that it's not even funny. This patch needs to die, and never *ever* be resurrected. Put a stake in it, and bury it 6ft deep. Linus -- 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/