From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39619) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VDsRt-0000A9-2x for qemu-devel@nongnu.org; Mon, 26 Aug 2013 04:47:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VDsRm-0005FP-WD for qemu-devel@nongnu.org; Mon, 26 Aug 2013 04:46:57 -0400 Received: from mx4-phx2.redhat.com ([209.132.183.25]:46667) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VDsRm-0005FF-PG for qemu-devel@nongnu.org; Mon, 26 Aug 2013 04:46:50 -0400 Date: Mon, 26 Aug 2013 04:43:19 -0400 (EDT) From: Andrew Jones Message-ID: <298159858.481798.1377506599931.JavaMail.root@redhat.com> In-Reply-To: <521B0EF7.2050203@cn.fujitsu.com> 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> <521B0EF7.2050203@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V9 06/12] NUMA: Add Linux libnuma detection List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: gaowanlong@cn.fujitsu.com, aliguori@us.ibm.com, pbonzini@redhat.com Cc: ehabkost@redhat.com, qemu-devel@nongnu.org, hutao@cn.fujitsu.com, peter huangpeng , lcapitulino@redhat.com, bsd@redhat.com, y-goto@jp.fujitsu.com, lersek@redhat.com, afaerber@suse.de ----- Original Message ----- > 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? Hmm, yeah, that's too bad that numaif.h is part of libnuma, and not a more general lib. Whether or not we want to redefine those symbols within qemu, in order to avoid the dependency on installing numactl-devel, isn't something I can answer. That's a better question for Anthony. Anthony? Paolo, any opinions? Maybe we should pick up uapi/linux/mempolicy.h with the linux-header synch script? thanks, drew > > Thanks, > Wanlong Gao > > > > > drew > > > >