Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750770AbVKJQSF (ORCPT ); Thu, 10 Nov 2005 11:18:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750899AbVKJQSE (ORCPT ); Thu, 10 Nov 2005 11:18:04 -0500 Received: from terminus.zytor.com ([192.83.249.54]:1505 "EHLO terminus.zytor.com") by vger.kernel.org with ESMTP id S1750770AbVKJQSD (ORCPT ); Thu, 10 Nov 2005 11:18:03 -0500 Message-ID: <43737274.1060105@zytor.com> Date: Thu, 10 Nov 2005 08:16:52 -0800 From: "H. Peter Anvin" User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: prasanna@in.ibm.com CC: Zachary Amsden , Ingo Molnar , Andi Kleen , virtualization@lists.osdl.org, Andrew Morton , Chris Wright , Linus Torvalds , Linux Kernel Mailing List , Zwane Mwaikambo , Martin Bligh , Pratap Subrahmanyam , Christopher Li , "Eric W. Biederman" , ananth@in.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net Subject: Re: [PATCH 19/21] i386 Kprobes semaphore fix References: <200511080439.jA84diI6009951@zach-dev.vmware.com> <200511081412.05285.ak@suse.de> <4370A9F5.4060103@vmware.com> <200511091438.11848.ak@suse.de> <437227FD.6040905@vmware.com> <20051109165804.GA15481@elte.hu> <43723768.2060103@vmware.com> <20051110180954.GD8514@in.ibm.com> In-Reply-To: <20051110180954.GD8514@in.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1081 Lines: 28 Prasanna S Panchamukhi wrote: > > As Ingo mentioned above, Systemtap uses kprobes infrastructure to provide > dynamic kernel instrumentation. Using which user can add lots of probes > easily, so we foreed to take care of this fast path. > > Instead of calling convert_eip_to_linear() for all cases, you can > just check if it is in kernel mode and calculate the address directly > > if (kernel mode) > addr = regs->eip - sizeof(kprobe_opcode_t); > else > addr = convert_eip_to_linear(..); > > there by avoiding call to convert_eip_to_linear () for every kernel probes. > > As Andi mentioned user space probes support is in progress and > this address conversion will help in case of user space probes as well. > Would it make sense for this to be part of convert_eip_to_linear? -hpa - 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/