Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756922Ab1CHVvH (ORCPT ); Tue, 8 Mar 2011 16:51:07 -0500 Received: from router-fw.net-space.pl ([89.174.63.77]:35981 "EHLO router-fw.net-space.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756824Ab1CHVuy (ORCPT ); Tue, 8 Mar 2011 16:50:54 -0500 Date: Tue, 8 Mar 2011 22:50:49 +0100 From: Daniel Kiper To: ian.campbell@citrix.com, akpm@linux-foundation.org, andi.kleen@intel.com, haicheng.li@linux.intel.com, fengguang.wu@intel.com, jeremy@goop.org, konrad.wilk@oracle.com, dan.magenheimer@oracle.com, v.tolstov@selfip.ru, pasik@iki.fi, dave@linux.vnet.ibm.com, wdauchy@gmail.com, rientjes@google.com, xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH R4 7/7] xen/balloon: Memory hotplug support for Xen balloon driver Message-ID: <20110308215049.GH27331@router-fw-old.local.net-space.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7236 Lines: 262 Memory hotplug support for Xen balloon driver. It should be mentioned that hotplugged memory is not onlined automatically. It should be onlined by user through standard sysfs interface. Signed-off-by: Daniel Kiper --- drivers/xen/Kconfig | 10 +++ drivers/xen/balloon.c | 154 +++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 159 insertions(+), 5 deletions(-) diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index 07bec09..8f880aa 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -9,6 +9,16 @@ config XEN_BALLOON the system to expand the domain's memory allocation, or alternatively return unneeded memory to the system. +config XEN_BALLOON_MEMORY_HOTPLUG + bool "Memory hotplug support for Xen balloon driver" + default n + depends on XEN_BALLOON && MEMORY_HOTPLUG + help + Memory hotplug support for Xen balloon driver allows expanding memory + available for the system above limit declared at system startup. + It is very useful on critical systems which require long + run without rebooting. + config XEN_SCRUB_PAGES bool "Scrub pages before returning them to system" depends on XEN_BALLOON diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 431e9f0..3dc8a83 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -6,6 +6,12 @@ * Copyright (c) 2003, B Dragovic * Copyright (c) 2003-2004, M Williamson, K Fraser * Copyright (c) 2005 Dan M. Smith, IBM Corporation + * Copyright (c) 2010 Daniel Kiper + * + * Memory hotplug support was written by Daniel Kiper. Work on + * it was sponsored by Google under Google Summer of Code 2010 + * program. Jeremy Fitzhardinge from Xen.org was the mentor for + * this project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 @@ -44,6 +50,9 @@ #include #include #include +#include +#include +#include #include #include @@ -93,6 +102,10 @@ struct balloon_stats { unsigned long max_schedule_delay; unsigned long retry_count; unsigned long max_retry_count; +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + unsigned long hotplug_pages; + unsigned long balloon_hotplug; +#endif }; static DEFINE_MUTEX(balloon_mutex); @@ -221,7 +234,93 @@ static enum bp_state update_schedule(enum bp_state state) return BP_EAGAIN; } -static unsigned long current_target(void) +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG +static long current_credit(void) +{ + return balloon_stats.target_pages - balloon_stats.current_pages - + balloon_stats.hotplug_pages; +} + +static int balloon_is_inflated(void) +{ + if (balloon_stats.balloon_low || balloon_stats.balloon_high || + balloon_stats.balloon_hotplug) + return 1; + else + return 0; +} + +static enum bp_state reserve_additional_memory(long credit) +{ + int rc; + unsigned long balloon_hotplug = credit; + + balloon_hotplug <<= PAGE_SHIFT; + + rc = add_virtual_memory((u64 *)&balloon_hotplug); + + if (rc) { + pr_info("xen_balloon: %s: add_virtual_memory() failed: %i\n", __func__, rc); + return BP_EAGAIN; + } + + balloon_hotplug >>= PAGE_SHIFT; + + balloon_hotplug -= credit; + + balloon_stats.hotplug_pages += credit; + balloon_stats.balloon_hotplug = balloon_hotplug; + + return BP_DONE; +} + +static int xen_online_page_notifier(struct notifier_block *nb, unsigned long val, void *v) +{ + struct page *page = v; + unsigned long pfn = page_to_pfn(page); + + if (pfn >= num_physpages) + num_physpages = pfn + 1; + + inc_totalhigh_pages(); + +#ifdef CONFIG_FLATMEM + max_mapnr = max(pfn, max_mapnr); +#endif + + mutex_lock(&balloon_mutex); + + __balloon_append(page); + + if (balloon_stats.hotplug_pages) + --balloon_stats.hotplug_pages; + else + --balloon_stats.balloon_hotplug; + + mutex_unlock(&balloon_mutex); + + return NOTIFY_STOP; +} + +static struct notifier_block xen_online_page_nb = { + .notifier_call = xen_online_page_notifier, + .priority = 10 +}; + +static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) +{ + if (val == MEM_ONLINE) + schedule_delayed_work(&balloon_worker, 0); + + return NOTIFY_OK; +} + +static struct notifier_block xen_memory_nb = { + .notifier_call = xen_memory_notifier, + .priority = 0 +}; +#else +static long current_credit(void) { unsigned long target = balloon_stats.target_pages; @@ -230,9 +329,24 @@ static unsigned long current_target(void) balloon_stats.balloon_low + balloon_stats.balloon_high); - return target; + return target - balloon_stats.current_pages; +} + +static int balloon_is_inflated(void) +{ + if (balloon_stats.balloon_low || balloon_stats.balloon_high) + return 1; + else + return 0; } +static enum bp_state reserve_additional_memory(long credit) +{ + balloon_stats.target_pages = balloon_stats.current_pages; + return BP_DONE; +} +#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ + static enum bp_state increase_reservation(unsigned long nr_pages) { int rc; @@ -244,6 +358,15 @@ static enum bp_state increase_reservation(unsigned long nr_pages) .domid = DOMID_SELF }; +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) { + nr_pages = min(nr_pages, balloon_stats.balloon_hotplug); + balloon_stats.hotplug_pages += nr_pages; + balloon_stats.balloon_hotplug -= nr_pages; + return BP_DONE; + } +#endif + if (nr_pages > ARRAY_SIZE(frame_list)) nr_pages = ARRAY_SIZE(frame_list); @@ -308,6 +431,15 @@ static enum bp_state decrease_reservation(unsigned long nr_pages) .domid = DOMID_SELF }; +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + if (balloon_stats.hotplug_pages) { + nr_pages = min(nr_pages, balloon_stats.hotplug_pages); + balloon_stats.hotplug_pages -= nr_pages; + balloon_stats.balloon_hotplug += nr_pages; + return BP_DONE; + } +#endif + if (nr_pages > ARRAY_SIZE(frame_list)) nr_pages = ARRAY_SIZE(frame_list); @@ -368,10 +500,14 @@ static void balloon_process(struct work_struct *work) mutex_lock(&balloon_mutex); do { - credit = current_target() - balloon_stats.current_pages; + credit = current_credit(); - if (credit > 0) - state = increase_reservation(credit); + if (credit > 0) { + if (balloon_is_inflated()) + state = increase_reservation(credit); + else + state = reserve_additional_memory(credit); + } if (credit < 0) state = decrease_reservation(-credit); @@ -458,6 +594,14 @@ static int __init balloon_init(void) balloon_stats.retry_count = 1; balloon_stats.max_retry_count = 16; +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + balloon_stats.hotplug_pages = 0; + balloon_stats.balloon_hotplug = 0; + + register_online_page_notifier(&xen_online_page_nb); + register_memory_notifier(&xen_memory_nb); +#endif + register_balloon(&balloon_sysdev); /* -- 1.5.6.5 -- 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/