This message generated a parse failure. Raw output follows here. Please use 'back' to navigate. From devnull@lkml.org Thu Apr 25 11:47:13 2024 Envelope-to: j@jasper.es Delivery-date: Fri, 26 Jul 2013 09:59:35 +0200 Received: from localhost ([127.0.0.1] helo=squeeze.vs19.net) by squeeze.vs19.net with esmtp (Exim 4.80) (envelope-from ) id 1V2cw2-0004DS-Ix for j@jasper.es; Fri, 26 Jul 2013 09:59:34 +0200 Original-Recipient: rfc822;jasper@telfort.nl Received: from pop3.telfort.nl [213.75.3.52] by squeeze.vs19.net with POP3 (fetchmail-6.3.18) for (single-drop); Fri, 26 Jul 2013 09:59:34 +0200 (CEST) Received: from cpxmta-msg03.kpnxchange.com (10.94.114.24) by cpxmbs-msg01.support.local (8.6.060.20) id 51B06D9500BF6AA1 for jasper@telfort.nl; Fri, 26 Jul 2013 09:48:43 +0200 Received: from cpsmtpb-ews06.kpnxchange.com (213.75.39.9) by cpxmta-msg03.kpnxchange.com (8.6.060.14) id 51AE806D0588AB30 for jasper@telfort.nl; Fri, 26 Jul 2013 09:48:43 +0200 Received: from cpsps-ews14.kpnxchange.com ([10.94.84.181]) by cpsmtpb-ews06.kpnxchange.com with Microsoft SMTPSVC(7.5.7601.17514); Fri, 26 Jul 2013 09:48:43 +0200 Received: from vger.kernel.org ([209.132.180.67]) by cpsps-ews14.kpnxchange.com with Microsoft SMTPSVC(7.5.7601.17514); Fri, 26 Jul 2013 09:48:43 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757022Ab3GZHs1 convert rfc822-to-quoted-printable (ORCPT ); Fri, 26 Jul 2013 03:48:27 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:26547 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752878Ab3GZHsZ convert rfc822-to-8bit (ORCPT ); Fri, 26 Jul 2013 03:48:25 -0400 X-Ironport-AV: E=Sophos;i="4.89,749,1367942400"; d="scan'208";a="8031703" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 26 Jul 2013 15:26:00 +0800 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id r6Q7L8eV002452; Fri, 26 Jul 2013 15:21:09 +0800 Received: from [10.167.226.100] ([10.167.226.100]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2013072615190436-154152 ; Fri, 26 Jul 2013 15:19:04 +0800 Message-Id: <51F22287.8050204@cn.fujitsu.com> Date: Fri, 26 Jul 2013 15:17:27 +0800 From: Gu Zheng User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 Mime-Version: 1.0 To: majianpeng Cc: viro , linux-fsdevel , linux-kernel Subject: Re: question about splice References: <201307261507562231224@gmail.com> In-Reply-To: <201307261507562231224@gmail.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/07/26 15:19:04, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/07/26 15:19:04 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-Id: X-Mailing-List: linux-kernel@vger.kernel.org X-OriginalArrivalTime: 26 Jul 2013 07:48:43.0032 (UTC) FILETIME=[8CE6A180:01CE89D4] X-RcptDomain: telfort.nl Hi Jianpeng, On 07/26/2013 03:08 PM, majianpeng wrote: > Hi all, > I used splice and found a prolem(at least i call). > The demo is: > A:splice(regularfileA--->pipe); > B:splice(pipe--->regularfileB) > Before do B, we modify the data of regA which now in pipe. The data t= o regularfileB willbe change. > If we used the buff > A:read(regA, buff); > B: write(buff, regB); > After A, the contend of regA can't effect the buff. > Review the code of splice,I know the pipe share the pagecache of regA= =2E Right. And also this is the splice's original design intention, using s= hare mmap rather than copy_to_user/copy_from_user in order to achieve zero-copy. Thanks, Gu > Maybe this is not a problem or am i missing something? >=20 > Thanks! > Jianpeng MaN=E5=AB=A5=E5=8F=89=E9=9D=A3=E7=AC=A1y=EE=8C=B7=E6=B0=8Ab=E7= =9E=82=EE=83=91=E5=8D=83v=E8=B1=9D=EF=BF=BD)=E8=97=93{.n=EF=BF=BD+=E5=A3= =8F=EE=9A=8F{=E7=9D=89=E8=B5=99zX=D0=A4=17=E6=B4=9D=E5=A1=84}=EE=9F=BB=E8= =B4=A2=E7=88=96=EF=BF=BD&j:+v=E5=A2=BE=EF=BF=BD=07=E7=8F=A3=E8=B5=99zZ+= =E2=82=AC=EF=BF=BD+zf=EF=BC=82=E7=A9=90=E6=AE=98=EE=9D=84=E5=95=B3=E5=97= =83i=EF=BF=BD=EE=8E=8Dz=EF=BF=BD=1E=E7=95=90=E3=82=A2=EF=BF=BD?=E6=AB=92= =E7=92=80=EF=BF=BD&=EF=BF=BD)=E6=92=B7=1Bf=E6=97=9F^j=E8=B0=A6y=EE=9C=B3= =E5=91=A9@A=E7=8E=9C=E5=9B=A4=7F=EF=BF=BD=0C0=E9=B9=85h=EF=BF=BD=0F=E9=8D= =9Ci=7F -- 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/