Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752009AbaBRSqv (ORCPT ); Tue, 18 Feb 2014 13:46:51 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:55183 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbaBRSqu (ORCPT ); Tue, 18 Feb 2014 13:46:50 -0500 X-IronPort-AV: E=Sophos;i="4.97,502,1389744000"; d="scan'208";a="101899742" Message-ID: <5303AA97.3010202@citrix.com> Date: Tue, 18 Feb 2014 18:46:47 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20121215 Iceowl/1.0b1 Icedove/3.0.11 MIME-Version: 1.0 To: Ian Campbell CC: Zoltan Kiss , , , , , Subject: Re: [Xen-devel] [PATCH net-next v5 2/9] xen-netback: Change TX path from grant copy to mapping References: <1390253069-25507-1-git-send-email-zoltan.kiss@citrix.com> <1390253069-25507-3-git-send-email-zoltan.kiss@citrix.com> <1392745235.23084.60.camel@kazak.uk.xensource.com> In-Reply-To: <1392745235.23084.60.camel@kazak.uk.xensource.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.2.76] X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/02/14 17:40, Ian Campbell wrote: > On Mon, 2014-01-20 at 21:24 +0000, Zoltan Kiss wrote: >> >> @@ -344,8 +346,26 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, >> vif->pending_prod = MAX_PENDING_REQS; >> for (i = 0; i < MAX_PENDING_REQS; i++) >> vif->pending_ring[i] = i; >> - for (i = 0; i < MAX_PENDING_REQS; i++) >> - vif->mmap_pages[i] = NULL; >> + spin_lock_init(&vif->dealloc_lock); >> + spin_lock_init(&vif->response_lock); >> + /* If ballooning is disabled, this will consume real memory, so you >> + * better enable it. > > Almost no one who would be affected by this is going to read this > comment. And it doesn't just require enabling ballooning, but actually > booting with some maxmem "slack" to leave space. > > Classic-xen kernels used to add 8M of slop to the physical address space > to leave a suitable pool for exactly this sort of thing. I never liked > that but perhaps it should be reconsidered (or at least raised as a > possibility with the core-Xen Linux guys). I plan to fix the balloon memory hotplug stuff to do the right thing (it's almost there -- it just tries to overlap the new memory with existing stuff). David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/