From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755125Ab2G3WM0 (ORCPT ); Mon, 30 Jul 2012 18:12:26 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:17246 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754929Ab2G3WMY (ORCPT ); Mon, 30 Jul 2012 18:12:24 -0400 X-Authority-Analysis: v=2.0 cv=StQSGYy0 c=1 sm=0 a=s5Htg7xnQOKvHEu9STBOug==:17 a=OpT9cpI26MMA:10 a=5qkZj-nraFkA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=ayC55rCoAAAA:8 a=3nbZYyFuAAAA:8 a=pGLkceISAAAA:8 a=20KFwNOVAAAA:8 a=k1IkWSz2LhNILjD5PckA:9 a=PUjeQqilurYA:10 a=EvKJbDF4Ut8A:10 a=jeBq3FmKZ4MA:10 a=MSl-tDqOz04A:10 a=jEp0ucaQiEUA:10 a=s5Htg7xnQOKvHEu9STBOug==:117 X-Cloudmark-Score: 0 X-Originating-IP: 72.230.195.127 Message-ID: <1343686341.27983.15.camel@gandalf.stny.rr.com> Subject: Re: [RFC PATCH 4/6] ftrace: Allow stealing pages from pipe buffer From: Steven Rostedt To: Yoshihiro YUNOMAE Cc: linux-kernel@vger.kernel.org, Amit Shah , Anthony Liguori , Arnd Bergmann , Borislav Petkov , "Franch Ch. Eigler" , Frederic Weisbecker , Greg Kroah-Hartman , Herbert Xu , Ingo Molnar , Mathieu Desnoyers , virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org, yrl.pp-manager.tt@hitachi.com, Masami Hiramatsu Date: Mon, 30 Jul 2012 18:12:21 -0400 In-Reply-To: <20120724023738.6600.59837.stgit@ltc189.sdl.hitachi.co.jp> References: <20120724023657.6600.52706.stgit@ltc189.sdl.hitachi.co.jp> <20120724023738.6600.59837.stgit@ltc189.sdl.hitachi.co.jp> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.4.3-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2012-07-24 at 11:37 +0900, Yoshihiro YUNOMAE wrote: > From: Masami Hiramatsu > > Use generic steal operation on pipe buffer to allow stealing > ring buffer's read page from pipe buffer. > > Note that this could reduce the performance of splice on the > splice_write side operation without affinity setting. > Since the ring buffer's read pages are allocated on the > tracing-node, but the splice user does not always execute > splice write side operation on the same node. In this case, > the page will be accessed from the another node. > Thus, it is strongly recommended to assign the splicing > thread to corresponding node. > > Signed-off-by: Masami Hiramatsu Acked-by: Steven Rostedt -- Steve > Cc: Frederic Weisbecker > Cc: Ingo Molnar > --- > > kernel/trace/trace.c | 8 +------- > 1 files changed, 1 insertions(+), 7 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index a120f98..ae01930 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -4194,12 +4194,6 @@ static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, > buf->private = 0; > } > > -static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe, > - struct pipe_buffer *buf) > -{ > - return 1; > -} > - > static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, > struct pipe_buffer *buf) > { > @@ -4215,7 +4209,7 @@ static const struct pipe_buf_operations buffer_pipe_buf_ops = { > .unmap = generic_pipe_buf_unmap, > .confirm = generic_pipe_buf_confirm, > .release = buffer_pipe_buf_release, > - .steal = buffer_pipe_buf_steal, > + .steal = generic_pipe_buf_steal, > .get = buffer_pipe_buf_get, > }; > >