Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756006AbZDKJbC (ORCPT ); Sat, 11 Apr 2009 05:31:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753811AbZDKJav (ORCPT ); Sat, 11 Apr 2009 05:30:51 -0400 Received: from yw-out-2324.google.com ([74.125.46.31]:47701 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753210AbZDKJau (ORCPT ); Sat, 11 Apr 2009 05:30:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=T+VohbLz6p6xK+MoTEyP6Jc7Tq/HFQmmQxiqz22iKXGoXbNCsdGl1T6tYmmUxLVXsy rYPkxFgKtwBGDh9G43wv82t+HX8XwQbdFOUVLl78PYRrWrnm7Pj9YSETPxawC25TvnoJ 0itJrXN+3lgxH/EvkcWq4vOnxltPKok/2I8dk= Subject: Re: [PATCH 0/7] tracing: bug fixes for tracing/filters From: Tom Zanussi To: Li Zefan Cc: Ingo Molnar , Steven Rostedt , Frederic Weisbecker , LKML , paulmck@linux.vnet.ibm.com In-Reply-To: <49E04C22.4040608@cn.fujitsu.com> References: <49E04C22.4040608@cn.fujitsu.com> Content-Type: text/plain Date: Sat, 11 Apr 2009 04:30:48 -0500 Message-Id: <1239442248.8793.65.camel@tropicana> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2144 Lines: 50 Hi, On Sat, 2009-04-11 at 15:52 +0800, Li Zefan wrote: > This patchset fixes some bugs in tracing/filters. Most of the change > goes to the last patch, and others are small ones. > At first glance, they look good and fix real problems - thanks for fixing them. Re patch 7, there's been some discussion about using rcu for this. See: http://lkml.org/lkml/2009/4/5/46 >From that discussion, it seems some non-trivial changes to rcu would be needed for this. I'm playing around with a different idea now to hopefully avoid the need for that, or the other approach mentioned, of temporarily stopping tracing while removing/changing the filters. Basically my thought is to avoid the problem by not allocating or destroying the preds when removing filters but instead switch out the pred->fns with a nop version while keeping the fields intact for awhile. I think that will work for removing filters, but I still need to think about how it would (or would not) work for replacing them. Tom > Maybe 3rd to 6th patches can be regarded as small enhancements instead > of bug fixes? But they are behavioural changes. > > > [PATCH 1/7] tracing/filters: NUL-terminate user input filter > [PATCH 2/7] tracing/filters: fix NULL pointer dereference > [PATCH 3/7] tracing/filters: allow user input integer to be oct or hex > [PATCH 4/7] tracing/filters: allow user to specify a filter val to be string > [PATCH 5/7] tracing/filters: disallow newline as delimeter > [PATCH 6/7] tracing/filters: return proper error code when writing filter file > [PATCH 7/7] tracing/filters: make filter preds RCU safe > > kernel/trace/trace.h | 6 +- > kernel/trace/trace_events.c | 16 +++-- > kernel/trace/trace_events_filter.c | 131 ++++++++++++++++++++++++++--------- > kernel/trace/trace_events_stage_3.h | 10 +++- > 4 files changed, 121 insertions(+), 42 deletions(-) > --- -- 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/