Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935370AbZDBGXQ (ORCPT ); Thu, 2 Apr 2009 02:23:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761309AbZDBGW5 (ORCPT ); Thu, 2 Apr 2009 02:22:57 -0400 Received: from yx-out-2324.google.com ([74.125.44.29]:20478 "EHLO yx-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756587AbZDBGW4 (ORCPT ); Thu, 2 Apr 2009 02:22:56 -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=GSjgM0h6O11PNhSS5lvw8ATdXQ9kP+A+/0PYpXU+dejgWv1rvcvLIEJohXFtmXFvDa OQamnkOOA8NpsgNVBmPGlFfcYA/Yz466JYBjg3fCixkrshlWN6yRktLKi2lWJmby/SHr xHsZ5Mixywj/Q9xncgZQiBSNm2AbmQVJp3ld4= Subject: Re: [PATCH] tracing/filters: allow event filters to be set only when not tracing From: Tom Zanussi To: Ingo Molnar Cc: linux-kernel , Steven Rostedt , fweisbec@gmail.com In-Reply-To: <20090401122408.GG12966@elte.hu> References: <1238390546.6368.65.camel@bookworm> <20090401122408.GG12966@elte.hu> Content-Type: text/plain Date: Thu, 02 Apr 2009 01:22:51 -0500 Message-Id: <1238653371.6655.48.camel@bookworm> 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: 1400 Lines: 38 On Wed, 2009-04-01 at 14:24 +0200, Ingo Molnar wrote: > * Tom Zanussi wrote: > > > This patch adds code allowing the event filter to be set only if > > there's no active tracing going on. > > > --- a/kernel/trace/trace_events.c > > +++ b/kernel/trace/trace_events.c > > @@ -498,6 +498,9 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, > > struct filter_pred *pred; > > int err; > > > > + if (tracing_is_enabled() && (!tracer_is_nop() || call->enabled)) > > + return -EBUSY; > > hm, but it would be the normal use-case to set filters on the fly. > To experiment around with them and shape them until the output is > just right. Having to turn the tracer on/off during that seems quite > counterproductive to that use-case. > I didn't see anything that could be used to temporarily disable tracing (tracing_stop() and tracing_start() are 'quick' versions that mostly just disable recording), so did it this way to avoid adding any overhead to the filter-checking code. But anyway, I'll post a new patch shortly that uses rcu and does allow the filters to be set on the fly. Tom > Ingo -- 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/