Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932314Ab0A2LbX (ORCPT ); Fri, 29 Jan 2010 06:31:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756349Ab0A2LbW (ORCPT ); Fri, 29 Jan 2010 06:31:22 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:44688 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756203Ab0A2LbV (ORCPT ); Fri, 29 Jan 2010 06:31:21 -0500 Subject: Re: [PATCH tracing/kprobes] kprobes: Disable booster when CONFIG_PREEMPT=y From: Peter Zijlstra To: Ingo Molnar Cc: Masami Hiramatsu , Thomas Gleixner , Fr??d??ric Weisbecker , Steven Rostedt , lkml , systemtap , DLE , Ananth N Mavinakayanahalli , Jim Keniston , Mathieu Desnoyers In-Reply-To: <20100129092135.GE10878@elte.hu> References: <4B5E476C.9030303@redhat.com> <20100127215531.24775.26807.stgit@dhcp-100-2-132.bos.redhat.com> <20100129092135.GE10878@elte.hu> Content-Type: text/plain; charset="UTF-8" Date: Fri, 29 Jan 2010 12:30:48 +0100 Message-ID: <1264764648.4283.2231.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 704 Lines: 17 On Fri, 2010-01-29 at 10:21 +0100, Ingo Molnar wrote: > * Masami Hiramatsu wrote: > > > Disable kprobe booster when CONFIG_PREEMPT=y, because it can't ensure that > > all kernel threads preempted on kprobe's boosted slot run out from the slot > > even using freeze_processes(). > > hm, this really sucks as it makes preemptible kernels perform worse. Is there > no better solution? We could pre-allocate 1 slot per kernel thread. -- 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/