From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752768Ab3KGBZT (ORCPT ); Wed, 6 Nov 2013 20:25:19 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:50043 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751361Ab3KGBZQ convert rfc822-to-8bit (ORCPT ); Wed, 6 Nov 2013 20:25:16 -0500 User-Agent: K-9 Mail for Android In-Reply-To: <527AE1CA.7030703@oracle.com> References: <1383770260-15395-1-git-send-email-boris.ostrovsky@oracle.com> <527AE1CA.7030703@oracle.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=UTF-8 Subject: Re: [Xen-devel] [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages From: Konrad Rzeszutek Wilk Date: Wed, 06 Nov 2013 20:25:04 -0500 To: Bob Liu , Boris Ostrovsky CC: david.vrabel@citrix.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Message-ID: <7ae8615f-36f4-4c28-a147-c522335ba8f7@email.android.com> X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bob Liu wrote: > >On 11/07/2013 04:37 AM, Boris Ostrovsky wrote: >> Currently balloon's initial value is set to max_pfn which includes >> non-RAM ranges such as MMIO hole. As result, initial memory target >> (specified by guest's configuration file) will appear smaller than >> what balloon driver perceives to be the current number of available >> pages. Thus it will balloon down "extra" pages, decreasing amount of >> available memory for no good reason. >> > >This fix the strange behavior I mentioned yesterday, every time after >guest started balloon driver will be triggered unreasonably. > >> Signed-off-by: Boris Ostrovsky >> --- >> drivers/xen/balloon.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c >> index b232908..1b62304 100644 >> --- a/drivers/xen/balloon.c >> +++ b/drivers/xen/balloon.c >> @@ -641,7 +641,7 @@ static int __init balloon_init(void) >> >> balloon_stats.current_pages = xen_pv_domain() >> ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) >> - : max_pfn; >> + : get_num_physpages(); > >By the way, should the other places using max_pfn also be changed with >get_num_physpages()? No. In PV that calculation is correct as it gets the amount of RAM pages - which is a exactly what you need. > >> balloon_stats.target_pages = balloon_stats.current_pages; >> balloon_stats.balloon_low = 0; >> balloon_stats.balloon_high = 0; >>