From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34175) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VDrzq-0006dL-6X for qemu-devel@nongnu.org; Mon, 26 Aug 2013 04:18:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VDrzj-0003xd-Nc for qemu-devel@nongnu.org; Mon, 26 Aug 2013 04:17:58 -0400 Received: from [222.73.24.84] (port=1659 helo=song.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VDrzj-0003vv-Bu for qemu-devel@nongnu.org; Mon, 26 Aug 2013 04:17:51 -0400 Message-ID: <521B0EF7.2050203@cn.fujitsu.com> Date: Mon, 26 Aug 2013 16:16:55 +0800 From: Wanlong Gao MIME-Version: 1.0 References: <1377231003-2816-1-git-send-email-gaowanlong@cn.fujitsu.com> <1377231003-2816-7-git-send-email-gaowanlong@cn.fujitsu.com> <433635292.2972869.1377247246639.JavaMail.root@redhat.com> <521AB2C1.40306@cn.fujitsu.com> <588686645.448144.1377503181634.JavaMail.root@redhat.com> In-Reply-To: <588686645.448144.1377503181634.JavaMail.root@redhat.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH V9 06/12] NUMA: Add Linux libnuma detection Reply-To: gaowanlong@cn.fujitsu.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrew Jones Cc: aliguori@us.ibm.com, ehabkost@redhat.com, qemu-devel@nongnu.org, hutao@cn.fujitsu.com, peter huangpeng , lcapitulino@redhat.com, bsd@redhat.com, y-goto@jp.fujitsu.com, pbonzini@redhat.com, lersek@redhat.com, afaerber@suse.de, Wanlong Gao On 08/26/2013 03:46 PM, Andrew Jones wrote: >>> Is this patch still necessary? I thought that dropping the >>> > > numa_num_configured_nodes() calls from patch 8/12 got rid >>> > > of the need for this library. Maybe I missed other uses? >> > >> > Yes, in 08/12 we also use mbind(), > You don't need a whole library for mbind(), it's a syscall. See syscall(2). > >> > and in 09/12 we use max_numa_node(). > Really? I didn't see it there. And anyway, that goes back to our discussion > about setting qemu's MAX_NODES to whatever we think qemu should support, > and then just checking that we don't blow that limit whenever reading > host node info, i.e. > > maxnode = 0; > while (host_nodes[maxnode] && maxnode < MAX_NODES) > node_read(&info[maxnode++]); > > type of a thing. > > And, if there's a place you really need to know the current online number > of host nodes, then, like I said earlier, you should just go to sysfs > yourself. libnuma:numa_max_node() returns an int that it only initializes > at library load time, so it's not going to adapt to onlining/offlining. OK, thank you. Then I should define MPOL_* macros in QEMU and use mbind(2) syscall directly, right? Thanks, Wanlong Gao > > drew >