From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH openvswitch v2] netlink: Implement & enable memory mapped netlink i/o Date: Mon, 02 Dec 2013 23:16:31 +0100 Message-ID: <529D06BF.1010701@redhat.com> References: <6a9efcafd9386ddd24fbfabb799bd2b5cc536430.1385814132.git.tgraf@redhat.com> <20131202212325.GG15335@nicira.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: jesse@nicira.com, dev@openvswitch.org, netdev@vger.kernel.org, dborkman@redhat.com, ffusco@redhat.com, fleitner@redhat.com, xiyou.wangcong@gmail.com To: Ben Pfaff Return-path: Received: from mx1.redhat.com ([209.132.183.28]:26275 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753033Ab3LBWRC (ORCPT ); Mon, 2 Dec 2013 17:17:02 -0500 In-Reply-To: <20131202212325.GG15335@nicira.com> Sender: netdev-owner@vger.kernel.org List-ID: On 12/02/2013 10:23 PM, Ben Pfaff wrote: > On Sat, Nov 30, 2013 at 01:27:33PM +0100, Thomas Graf wrote: >> Based on the initial patch by Cong Wang posted a couple of months >> ago. >> >> This is the user space counterpart needed for the kernel patch >> '[PATCH net-next 3/8] openvswitch: Enable memory mapped Netlink i/o' >> >> Allows the kernel to construct Netlink messages on memory mapped >> buffers and thus avoids copying. The functionality is enabled on >> sockets used for unicast traffic. >> >> Further optimizations are possible by avoiding the copy into the >> ofpbuf after reading. >> >> Signed-off-by: Thomas Graf > > Clang reports: > > ../lib/netlink-socket.c:330:12: error: cast from 'char *' to 'struct nl_mmap_hdr *' increases required alignment from 1 to 4 [-Werror,-Wcast-align] > return (struct nl_mmap_hdr *)(start + r->head * sock->frame_size); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ../lib/netlink-socket.c:369:22: error: implicit declaration of function '__ALIGN_KERNEL' is invalid in C99 [-Werror,-Wimplicit-function-declaration] > -> sock->frame_size) > ^ > ../lib/netlink-protocol.h:213:26: note: expanded from macro 'NL_MMAP_HDRLEN' > #define NL_MMAP_HDRLEN NL_MMAP_MSG_ALIGN(sizeof(struct nl_mmap_hdr)) > ^ > ../lib/netlink-protocol.h:212:32: note: expanded from macro 'NL_MMAP_MSG_ALIGN' > #define NL_MMAP_MSG_ALIGN(sz) __ALIGN_KERNEL(sz, NL_MMAP_MSG_ALIGNMENT) > ^ > GCC reports: > > ../lib/netlink-socket.c: In function 'nl_sock_send_mmap': > ../lib/netlink-socket.c:369:5: error: implicit declaration of function '__ALIGN_KERNEL' [-Werror=implicit-function-declaration] > cc1: all warnings being treated as errors Just so we can simplify this process: what's the oldest environment you want the code to compile on?