From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752718Ab3FYIqK (ORCPT ); Tue, 25 Jun 2013 04:46:10 -0400 Received: from mail-ee0-f53.google.com ([74.125.83.53]:51273 "EHLO mail-ee0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751876Ab3FYIqH (ORCPT ); Tue, 25 Jun 2013 04:46:07 -0400 Date: Tue, 25 Jun 2013 10:46:00 +0200 From: Robert Richter To: Borislav Petkov Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Jiri Olsa , linux-kernel@vger.kernel.org, Borislav Petkov Subject: Re: [PATCH v2 02/14] perf: Add persistent events Message-ID: <20130625084600.GB21579@rric.localhost> References: <1370968960-22527-1-git-send-email-rric@kernel.org> <1370968960-22527-3-git-send-email-rric@kernel.org> <20130624092807.GM28407@twins.programming.kicks-ass.net> <20130624192404.GA24827@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130624192404.GA24827@pd.tnic> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24.06.13 21:24:04, Borislav Petkov wrote: > On Mon, Jun 24, 2013 at 11:28:07AM +0200, Peter Zijlstra wrote: > > I find this patch incomplete for its asymmetric; there a dec, but not an > > implied inc. > > There's one in perf_mmap_open. > > Basically the idea was to pull up the ->mmap_count decrement (haha, > sounds like excrement :-)) and not deallocate the ring buffers for a > persistent event. The asymmetry comes from rb_alloc() in add_persistent_event_on_cpu() which is usually implemented in the mmap functions. We might better improve functions to attach/detach events and buffers for more symmetric code. -Robert