From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755165Ab2IFIAZ (ORCPT ); Thu, 6 Sep 2012 04:00:25 -0400 Received: from ozlabs.org ([203.10.76.45]:40894 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752501Ab2IFIAU (ORCPT ); Thu, 6 Sep 2012 04:00:20 -0400 From: Rusty Russell To: "Michael S. Tsirkin" Cc: Sasha Levin , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, avi@redhat.com, kvm@vger.kernel.org Subject: Re: [PATCH v2 2/2] virtio-ring: Allocate indirect buffers from cache when possible In-Reply-To: <20120906050257.GA17656@redhat.com> References: <1346159043-16446-1-git-send-email-levinsasha928@gmail.com> <1346159043-16446-2-git-send-email-levinsasha928@gmail.com> <20120828132032.GB2039@redhat.com> <503CC904.3050207@gmail.com> <20120829110748.GB5970@redhat.com> <503E2F27.5060904@gmail.com> <20120829153833.GE7407@redhat.com> <503E4873.6060607@gmail.com> <871uigj747.fsf@rustcorp.com.au> <20120906050257.GA17656@redhat.com> User-Agent: Notmuch/0.13.2 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Thu, 06 Sep 2012 17:27:23 +0930 Message-ID: <877gs7inx8.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Michael S. Tsirkin" writes: > Yes without checksum net core always linearizes packets, so yes it is > screwed. > For -net, skb always allocates space for 17 frags + linear part so > it seems sane to do same in virtio core, and allocate, for -net, > up to max_frags + 1 from cache. > We can adjust it: no _SG -> 2 otherwise 18. But I thought it used individual buffers these days? Cheers, Rusty.