From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752478Ab1IXU6q (ORCPT ); Sat, 24 Sep 2011 16:58:46 -0400 Received: from rcsinet15.oracle.com ([148.87.113.117]:61808 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752361Ab1IXU6p convert rfc822-to-8bit (ORCPT ); Sat, 24 Sep 2011 16:58:45 -0400 MIME-Version: 1.0 Message-ID: <9827a70d-dfb2-4bbc-9df6-207b10c835ac@default> Date: Sat, 24 Sep 2011 13:58:08 -0700 (PDT) From: Dan Magenheimer To: Konrad Wilk , linux-kernel@vger.kernel.org Cc: xen-devel@lists.xensource.com, David Vrabel , Jeremy Fitzhardinge Subject: [PATCH] xen: Fix selfballooning and ensure it doesn't go too far X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.4.1.0 (410211) [OL 12.0.6557.5001] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT X-Source-IP: acsinet21.oracle.com [141.146.126.237] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090208.4E7E4480.0020:SCFMA922111,ss=1,re=-4.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [PATCH] xen: Fix selfballooning and ensure it doesn't go too far The balloon driver's "current_pages" is very different from totalram_pages. Self-ballooning needs to be driven by the latter. Also, Committed_AS doesn't account for pages used by the kernel so enforce a floor for when there are little or no user-space threads using memory. Signed-off-by: Dan Magenheimer diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c index 6ea852e..e3e48f1 100644 --- a/drivers/xen/xen-selfballoon.c +++ b/drivers/xen/xen-selfballoon.c @@ -195,14 +195,13 @@ __setup("selfballooning", xen_selfballooning_setup); */ static void selfballoon_process(struct work_struct *work) { - unsigned long cur_pages, goal_pages, tgt_pages; + unsigned long cur_pages, goal_pages, tgt_pages, floor_pages; bool reset_timer = false; if (xen_selfballooning_enabled) { - cur_pages = balloon_stats.current_pages; + cur_pages = totalram_pages; tgt_pages = cur_pages; /* default is no change */ - goal_pages = percpu_counter_read_positive(&vm_committed_as) + - balloon_stats.current_pages - totalram_pages; + goal_pages = percpu_counter_read_positive(&vm_committed_as); #ifdef CONFIG_FRONTSWAP /* allow space for frontswap pages to be repatriated */ if (frontswap_selfshrinking && frontswap_enabled) @@ -217,7 +216,13 @@ static void selfballoon_process(struct work_struct *work) ((goal_pages - cur_pages) / selfballoon_uphysteresis); /* else if cur_pages == goal_pages, no change */ - balloon_set_new_target(tgt_pages); + floor_pages = totalreserve_pages + + (roundup_pow_of_two(max_pfn) >> 5); + /* don't balloon too far, lest OOMs occur... */ + if (tgt_pages < floor_pages) + tgt_pages = floor_pages; + balloon_set_new_target(tgt_pages + + balloon_stats.current_pages - totalram_pages); reset_timer = true; } #ifdef CONFIG_FRONTSWAP