From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761405AbZAWOJw (ORCPT ); Fri, 23 Jan 2009 09:09:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756610AbZAWOJm (ORCPT ); Fri, 23 Jan 2009 09:09:42 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:13018 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757208AbZAWOJl (ORCPT ); Fri, 23 Jan 2009 09:09:41 -0500 X-IronPort-AV: E=Sophos;i="4.37,312,1231131600"; d="scan'208";a="36918171" Subject: Re: [Xen-devel] [PATCH] xen: actually release memory when shrinking domain From: Ian Campbell To: Jeremy Fitzhardinge Cc: Ingo Molnar , "dan.magenheimer@oracle.com" , Xen-devel , Linux Kernel Mailing List , Stable Kernel In-Reply-To: <4978F4D8.6090706@goop.org> References: <4978F4D8.6090706@goop.org> Content-Type: text/plain Organization: Citrix Systems, Inc. Date: Fri, 23 Jan 2009 14:09:08 +0000 Message-Id: <1232719748.27712.19.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 23 Jan 2009 14:09:40.0275 (UTC) FILETIME=[3B5A6030:01C97D64] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2009-01-22 at 14:36 -0800, Jeremy Fitzhardinge wrote: > From: Dan Magenheimer > > Fix this: > > > It appears that in the upstream balloon driver, > > > the call to HYPERVISOR_update_va_mapping is missing > > > from decrease_reservation. I think as a result, > > > the balloon driver is eating memory but not > > > releasing it to Xen, thus rendering the balloon > > > driver essentially useless. (Can be observed via xentop.) Fails on 32 bit with HighMem pages: kernel BUG at /local/scratch/ianc/devel/kernels/paravirt/drivers/xen/balloon.c:298! invalid opcode: 0000 [#1] SMP last sysfs file: /sys/devices/system/xen_memory/xen_memory0/info/current_kb Modules linked in: Pid: 9, comm: events/0 Tainted: G W (2.6.29-rc1-x86_32p-xen0-tip #726) EIP: 0061:[] EFLAGS: 00010282 CPU: 0 EIP is at balloon_process+0x527/0x530 EAX: ffffffea EBX: deadbeef ECX: deadbeef EDX: deadbeef ESI: deadbeef EDI: c1000000 EBP: 00000000 ESP: f64b5f44 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0069 Process events/0 (pid: 9, ti=f64b4000 task=f642d830 task.ti=f64b4000) Stack: 00000000 ffffa0c0 0000002e 00000192 0000019d 00000000 00000400 f6427a00 00000000 00000000 00000000 00000000 00007ff0 c04afcb0 f6427a00 c04afcac c0266730 c0143cf1 c0106bc2 f6427a0c c0107810 f642020c f6427a04 f6427a0c Call Trace: [] balloon_process+0x0/0x530 [] run_workqueue+0x91/0x140 [] check_events+0x8/0x16 [] xen_spin_unlock+0x0/0x50 [] autoremove_wake_function+0x0/0x50 [] worker_thread+0x98/0xf0 [] autoremove_wake_function+0x0/0x50 [] worker_thread+0x0/0xf0 [] kthread+0x42/0x70 [] kthread+0x0/0x70 [] kernel_thread_helper+0x7/0x10 Code: 00 00 00 00 e8 9b a1 f0 ff 31 f6 e8 e4 2f eb ff b8 e0 7b 54 c0 e8 1a 90 16 00 8b 6c 24 18 89 44 24 14 89 74 24 10 e9 eb fe ff ff <0f> 0b eb fe 90 8d 74 26 00 83 ec 04 b8 20 fc 4a c0 e8 13 dc ff EIP: [] balloon_process+0x527/0x530 SS:ESP 0069:f64b5f44 ---[ end trace 4eaa2a86a8e2da28 ]--- diff -r b64a63f076cd drivers/xen/balloon.c --- a/drivers/xen/balloon.c Fri Jan 23 13:29:48 2009 +0000 +++ b/drivers/xen/balloon.c Fri Jan 23 14:09:08 2009 +0000 @@ -292,10 +292,13 @@ scrub_page(page); - ret = HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - __pte_ma(0), 0); - BUG_ON(ret); + if (!PageHighMem(page)) { + ret = HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << PAGE_SHIFT), + __pte_ma(0), 0); + BUG_ON(ret); + } + } /* Ensure that ballooned highmem pages don't have kmaps. */