Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757322AbZDXU56 (ORCPT ); Fri, 24 Apr 2009 16:57:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751188AbZDXU5u (ORCPT ); Fri, 24 Apr 2009 16:57:50 -0400 Received: from ey-out-2122.google.com ([74.125.78.27]:51767 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751083AbZDXU5t (ORCPT ); Fri, 24 Apr 2009 16:57:49 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=irKdwk1E2vH3zdqyGZ6wEup6uX6eNKyc3E19AfrJ9sJk2LACAFPEF8aGedLxgW9Rwv A+Xbb6WmfCnE8av/hymnZZbqKMtnXyHREyH11stxsTx4/XvcRoG9gtxNeQqg6kxYvDvq 9QqtIrjzoDP3DQOZwMvFXOm7awXTyZL7BsO1E= Date: Fri, 24 Apr 2009 22:57:44 +0200 From: Frederic Weisbecker To: "K.Prasad" Cc: Alan Stern , Steven Rostedt , Ingo Molnar , Linux Kernel Mailing List , Andrew Morton , Benjamin Herrenschmidt , maneesh@linux.vnet.ibm.com, Roland McGrath , Steven Rostedt Subject: Re: [Patch 11/12] ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces - v3 Message-ID: <20090424205741.GA6009@nowhere> References: <20090424055710.764502564@prasadkr_t60p.in.ibm.com> <20090424061849.GL23812@in.ibm.com> <20090424072141.GC5993@nowhere> <20090424091347.GA29830@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090424091347.GA29830@in.ibm.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 Content-Length: 2408 Lines: 61 On Fri, Apr 24, 2009 at 02:43:47PM +0530, K.Prasad wrote: > On Fri, Apr 24, 2009 at 09:21:42AM +0200, Frederic Weisbecker wrote: > > On Fri, Apr 24, 2009 at 11:48:50AM +0530, K.Prasad wrote: > > > This patch adds an ftrace plugin to detect and profile memory access over kernel > > > variables. It uses HW Breakpoint interfaces to 'watch memory addresses. > > > > > > Just a small concern, but it would be nice if you could include the history > > of this patch in the changelogs. > > > > > > > > Hi Frederic, > Thanks for looking into the patch. I will provide the history of > changes here. The ULONG_MAX definition from linux/kernel.h is now used > and the permission for the 'ksym_trace_filter' file is now set to 644 > (similar to other ftrace plugin filters). > > Changelog > --------- > (since the first post of this patch here: http://lkml.org/lkml/2009/3/4/418) > > - Addition of a startup selftest to test basic sanity of HW Breakpoint > infrastructure. > - Implementation of a ftrace's stats facility over ksym_tracer to > provide aggregate 'hit' counter values. > - Conversion of all locking primitives into spinlocks (ksym_tracer_lock) > from previous mutex implementation (since stats collection happens inside > the context of the breakpoint exception and we cannot sleep). > - A few changes in ksym_trace_filter_write() and > process_new_ksym_entry() to eliminate passing of unnecessary values. > - Fixed a few potential memory leak scenarios (missing kfree() > operations in return path) along with other minor issues pointed out in LKML. > - Minor code changes such as unconditional definition of 'struct > trace_ksym' - irrespective of CONFIG_KSYM_TRACER. Thanks! Such history is very useful to understand a patch. They can explain some logic reasoning of a patch, especially between versions. > ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces - v3 > > This patch adds an ftrace plugin to detect and profile memory access over kernel > variables. It uses HW Breakpoint interfaces to 'watch memory addresses. > > Signed-off-by: K.Prasad It looks good. Thanks! -- 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/