From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <huawei.xie@intel.com> Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 01650C36E for <dev@dpdk.org>; Fri, 10 Jul 2015 17:32:47 +0200 (CEST) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP; 10 Jul 2015 08:32:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,447,1432623600"; d="scan'208";a="603771787" Received: from pgsmsx103.gar.corp.intel.com ([10.221.44.82]) by orsmga003.jf.intel.com with ESMTP; 10 Jul 2015 08:32:45 -0700 Received: from shsmsx103.ccr.corp.intel.com (10.239.4.69) by PGSMSX103.gar.corp.intel.com (10.221.44.82) with Microsoft SMTP Server (TLS) id 14.3.224.2; Fri, 10 Jul 2015 23:32:44 +0800 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.246]) by SHSMSX103.ccr.corp.intel.com ([169.254.4.46]) with mapi id 14.03.0224.002; Fri, 10 Jul 2015 23:32:37 +0800 From: "Xie, Huawei" <huawei.xie@intel.com> To: Pavel Boldin <pboldin@mirantis.com> Thread-Topic: [dpdk-dev] [PATCH v5 4/5] vhost: eventfd_link: replace copy-pasted sys_close Thread-Index: AdC7JaWGV8dlCf+ynE6WaHWpLcGybQ== Date: Fri, 10 Jul 2015 15:32:36 +0000 Message-ID: <C37D651A908B024F974696C65296B57B0F56C68F@SHSMSX101.ccr.corp.intel.com> References: <1427994080-10163-1-git-send-email-pboldin@mirantis.com> <1429184910-30186-5-git-send-email-pboldin@mirantis.com> <C37D651A908B024F974696C65296B57B0F476567@SHSMSX101.ccr.corp.intel.com> <1665929.SfCu3BinAE@xps13> <C37D651A908B024F974696C65296B57B0F56C326@SHSMSX101.ccr.corp.intel.com> <CACf4_B_2M-Nc76kTDwxySgjS3LzYgJVLFz0GgNcWEpz-96WipQ@mail.gmail.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" <dev@dpdk.org> Subject: Re: [dpdk-dev] [PATCH v5 4/5] vhost: eventfd_link: replace copy-pasted sys_close X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Fri, 10 Jul 2015 15:32:48 -0000 On 7/10/2015 10:50 PM, Pavel Boldin wrote: Xie, Regarding the patches: 1. The replaced code in fourth patch is checked to be a copy-paste of the `= sys_close` syscall. sys_close does extra cleanup than the replaced code. My concern is, for exa= mple, sys_close will mark the fd as next-to-be-allocated fd. Will there be = issue when we allocate a new fd? Because it will be allocated starting from= the next-to-be-allocated-fd. I think Kernel will do some check on that val= ue, but not sure. 2. It is not uncommon for the applications to close FD making it allocated = for a different file. In our particular case the file is closed in the *sou= rce* process and *added* to a target process, so matching fds should not be= the problem. Sure, that is what the old code does. 3. There is an implementation of the exact same thing in the SCM_RIGHTS [1]= that can be used as the reference code. I did a rough check. Maybe i miss something. I see it calls fd_install on a= newly allocated fd. That is exactly what i think is the clean fix. Currently we allocate eventfd in user space, and install a new file onto it= . Actually we don't need to allocate eventfd in user space at all, what we= should do is allocate a new fd, and install the file on the newly allocate= d fd. new_fd =3D get_unused_fd_flags(...) fd_install(new_fd, get_file(fp[i])); /huawei [1] https://github.com/torvalds/linux/blob/master/net/core/scm.c#L248 Pavel On Fri, Jul 10, 2015 at 5:27 PM, Xie, Huawei <huawei.xie@intel.com<mailto:h= uawei.xie@intel.com>> wrote: On 6/17/2015 11:24 PM, Thomas Monjalon wrote: > 2015-05-07 06:54, Xie, Huawei: >> On 4/16/2015 7:48 PM, Pavel Boldin wrote: >>> + /* Closing the source_fd */ >>> + ret =3D sys_close(eventfd_copy.source_fd); >> Pavel: >> Here we close the fd and re-install a new file on this fd later. >> sys_close does all cleanup. >> But, for instance, if we allocate new fd later, normally it will reuse >> the just freed fds by sys_close, is there issue here? > Pavel, Huawei, > Could we come to a conclusion on this patch series please? For the previous 3 patches, i am OK except that i don't think inline is needed explicitly for non-performance critical function. For this patch, didn't check the fs code. > >