From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753112AbaENILd (ORCPT ); Wed, 14 May 2014 04:11:33 -0400 Received: from e06smtp11.uk.ibm.com ([195.75.94.107]:48695 "EHLO e06smtp11.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253AbaENIL1 (ORCPT ); Wed, 14 May 2014 04:11:27 -0400 Date: Wed, 14 May 2014 10:11:15 +0200 From: Michael Mueller To: "Michael S. Tsirkin" Cc: Romain Francoise , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, borntraeger@de.ibm.com, cornelia.huck@de.ibm.com, ddongch@cn.ibm.com Subject: Re: [PATCH v1] vhost: avoid large order allocations Message-ID: <20140514101115.4b7ffd69@bee> In-Reply-To: <20140513151527.GA28517@redhat.com> References: <1399970133-46783-1-git-send-email-mimu@linux.vnet.ibm.com> <1399970133-46783-2-git-send-email-mimu@linux.vnet.ibm.com> <20140513084049.GE29442@redhat.com> <87tx8tg3a1.fsf@kima.orebokech.com> <20140513151527.GA28517@redhat.com> Organization: IBM X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.13; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14051408-5024-0000-0000-000009D255BF Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 May 2014 18:15:27 +0300 "Michael S. Tsirkin" wrote: > On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote: > > "Michael S. Tsirkin" writes: > > > > > Please dont' do this, extra indirection hurts performance. > > > Instead, please change vhost_net_open and scsi to allocate the whole > > > structure with vmalloc if kmalloc fails, along the lines of > > > 74d332c13b2148ae934ea94dac1745ae92efe8e5 > > > > Back in January 2013, you didn't seem to think it was a good idea: > > > > https://lkml.org/lkml/2013/1/23/492 > > Hmm true, and Dave thought the structure's too large. > I'll have to do some benchmarks to see what the effect > of Michael's patch is, performance-wise. > If it's too expensive I can pick up your patch, no need to > repost. > Thanks, let us know then.