From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH 0/3][RFC] NUMA: add host side pinning Date: Mon, 28 Jun 2010 11:17:55 -0500 Message-ID: <4C28CB33.8030101@codemonkey.ws> References: <1277327377-29629-1-git-send-email-andre.przywara@amd.com> <4C2288DD.3020207@codemonkey.ws> <865764AB-4E51-4ED4-8832-AED6A237A9D3@suse.de> <4C233A6D.7030805@amd.com> <4C233DAB.60106@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Andre Przywara , Alexander Graf , "kvm@vger.kernel.org" To: Avi Kivity Return-path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:32937 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665Ab0F1QR7 (ORCPT ); Mon, 28 Jun 2010 12:17:59 -0400 Received: by yxi11 with SMTP id 11so46473yxi.19 for ; Mon, 28 Jun 2010 09:17:58 -0700 (PDT) In-Reply-To: <4C233DAB.60106@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/24/2010 06:12 AM, Avi Kivity wrote: > On 06/24/2010 01:58 PM, Andre Przywara wrote: >>> So who would create the /dev/shm/nodeXX files? >> >> Currently it is QEMU. It creates a somewhat unique filename, opens >> and unlinks it. The difference would be to name the file after the >> option and to not unlink it. >> >> > I can imagine starting numactl before qemu, even though that's >> > cumbersome. I don't think it's feasible to start numactl after >> > qemu is running. That'd involve way too much magic that I'd prefer >> > qemu to call numactl itself. >> Using the current code the files would not exist before QEMU >> allocated RAM, and after that it could already touch pages before >> numactl set the policy. > > Non-anonymous memory doesn't work well with ksm and transparent > hugepages. Is it possible to use anonymous memory rather than file > backed? You aren't going to be doing NUMA pinning and KSM AFAICT. Regards, Anthony Liguori >> To avoid this I'd like to see the pinning done from within QEMU. I am >> not sure whether calling numactl via system() and friends is OK, I'd >> prefer to run the syscalls directly (like in patch 3/3) and pull the >> necessary options into the -numa pin,... command line. We could mimic >> numactl's syntax here. > > Definitely not use system(), but IIRC numactl has a library interface? > >