From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756311Ab3AOD1h (ORCPT ); Mon, 14 Jan 2013 22:27:37 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:5043 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755345Ab3AOD1L (ORCPT ); Mon, 14 Jan 2013 22:27:11 -0500 X-Authority-Analysis: v=2.0 cv=T70Ovo2Q c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=Ciwy3NGCPMMA:10 a=Om9gs21YYNIA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=jI7U8BSgD1AA:10 a=yPCof4ZbAAAA:8 a=VwQbUJbxAAAA:8 a=173D2eteMl7QsvqjTiQA:9 a=QEXdDO2ut3YA:10 a=2cfT85sH4i8A:10 a=7DSvI1NPTFQA:10 a=jeBq3FmKZ4MA:10 a=3l7LBOaamcw3dpvTSr4A:9 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-Id: <20130115032710.277660195@goodmis.org> User-Agent: quilt/0.60-1 Date: Mon, 14 Jan 2013 22:20:44 -0500 From: Steven Rostedt To: Linus Torvalds , linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Frederic Weisbecker , Liu Bo Subject: [PATCH 2/2] tracing: Fix regression of trace_pipe References: <20130115032042.472099050@goodmis.org> Content-Disposition: inline; filename=0002-tracing-Fix-regression-of-trace_pipe.patch Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="00GvhwF7k39YY" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --00GvhwF7k39YY Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable From: Liu Bo Commit 0fb9656d "tracing: Make tracing_enabled be equal to tracing_on" changes the behaviour of trace_pipe, ie. it makes trace_pipe return if we've read something and tracing is enabled, and this means that we have to 'cat trace_pipe' again and again while running tests. IMO the right way is if tracing is enabled, we always block and wait for ring buffer, or we may lose what we want since ring buffer's size is limite= d. Link: http://lkml.kernel.org/r/1358132051-5410-1-git-send-email-bo.li.liu@o= racle.com Signed-off-by: Liu Bo Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f3ec1cf..3c13e46 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3454,7 +3454,7 @@ static int tracing_wait_pipe(struct file *filp) return -EINTR; =20 /* - * We block until we read something and tracing is enabled. + * We block until we read something and tracing is disabled. * We still block if tracing is disabled, but we have never * read anything. This allows a user to cat this file, and * then enable tracing. But after we have read something, @@ -3462,7 +3462,7 @@ static int tracing_wait_pipe(struct file *filp) * * iter->pos will be 0 if we haven't read anything. */ - if (tracing_is_enabled() && iter->pos) + if (!tracing_is_enabled() && iter->pos) break; } =20 --=20 1.7.10.4 --00GvhwF7k39YY Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJQ9MyOAAoJEOdOSU1xswtMSCIH/iFAYc5Zy5mk5/+IDflSjqZK dEANl9/8Z57JQN5zVWCkjl1AYKho3v94h5yWBjdA06RSmIB58MspmzsQdmoulUHh deu03qN9qKeDk21i4XpVMTxXGdp4OlP9VCUFni64u4a8f3wmdLQqQTpCKxxkvPm0 U4jaDUCwDs1IjA3DAK00yq9nxRDowbXM3iDLzQKxOxYv97sJkSu3XiOVL4EGbs/5 Y9xjdanV3kHr/WaIjhlp2cnwIKpFkg03wl8nahe1xgN3NKTa0RwvHCz6Pxh6thKb oEcbn4l8UeQ7QUiIg6PFGyGDRqRAdoJgkrb4PVJJZdeQ6V3+fySIZGNk5zQ31QY= =gX+O -----END PGP SIGNATURE----- --00GvhwF7k39YY--