From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753742Ab3B1UDG (ORCPT ); Thu, 28 Feb 2013 15:03:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:64923 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752599Ab3B1UDD (ORCPT ); Thu, 28 Feb 2013 15:03:03 -0500 Date: Thu, 28 Feb 2013 21:01:17 +0100 From: Oleg Nesterov To: Anton Arapov Cc: Srikar Dronamraju , LKML , Josh Stone , Frank Eigler , Peter Zijlstra , Ingo Molnar , Ananth N Mavinakayanahalli Subject: Re: [RFC PATCH v3 3/6] uretprobes: generalize xol_get_insn_slot() Message-ID: <20130228200117.GA9074@redhat.com> References: <1362049215-5780-1-git-send-email-anton@redhat.com> <1362049215-5780-4-git-send-email-anton@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1362049215-5780-4-git-send-email-anton@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Anton, I'll try to read this series asap. Just one note, On 02/28, Anton Arapov wrote: > > Generalize xol_take_insn_slot() to enable more consumers of the > function, e.g. trampoline implementation for return probes. Yes, this is can work too. But I guess you misunderstood me, or I missed something... Why do you need xol_area->rp_trampoline_vaddr at all? From the very beginning I am trying to suggest to use the first slot for trampoline: Or. Perhaps even better, do not add this helper at all. xol_alloc_area() could reserve the first slot/bit for trampoline. And note that in this case we do not need xol_area->rp_trampoline_vaddr, it is always equal to xol_area->vaddr. Doesn't this look simpler? Oleg.