Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756910Ab1CHVuz (ORCPT ); Tue, 8 Mar 2011 16:50:55 -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 S1756376Ab1CHVuy (ORCPT ); Tue, 8 Mar 2011 16:50:54 -0500 Date: Tue, 8 Mar 2011 22:50:03 +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 6/7] mm: Extend memory hotplug API to allow memory hotplug in virtual guests Message-ID: <20110308215003.GG27331@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: 6812 Lines: 198 This patch extends memory hotplug API to allow easy memory hotplug in virtual guests. It contains: - generic section aligment macro, - online_page_chain and apropriate functions for registering/unregistering online page notifiers, - add_virtual_memory(u64 *size) function which adds memory region of size >= *size above max_pfn; new region is section aligned and size is modified to be multiple of section size. Signed-off-by: Daniel Kiper --- include/linux/memory_hotplug.h | 6 ++- include/linux/mmzone.h | 2 + mm/memory_hotplug.c | 91 +++++++++++++++++++++++++++++++++++++++- 3 files changed, 95 insertions(+), 4 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 8122018..4cfc5a0 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -68,12 +68,13 @@ static inline void zone_seqlock_init(struct zone *zone) extern int zone_grow_free_lists(struct zone *zone, unsigned long new_nr_pages); extern int zone_grow_waitqueues(struct zone *zone, unsigned long nr_pages); extern int add_one_highpage(struct page *page, int pfn, int bad_ppro); -/* need some defines for these for archs that don't support it */ -extern void online_page(struct page *page); /* VM interface that may be used by firmware interface */ extern int online_pages(unsigned long, unsigned long); extern void __offline_isolated_pages(unsigned long, unsigned long); +extern int register_online_page_notifier(struct notifier_block *nb); +extern int unregister_online_page_notifier(struct notifier_block *nb); + #ifdef CONFIG_MEMORY_HOTREMOVE extern bool is_pageblock_removable_nolock(struct page *page); #endif /* CONFIG_MEMORY_HOTREMOVE */ @@ -224,6 +225,7 @@ static inline int is_mem_section_removable(unsigned long pfn, extern int mem_online_node(int nid); extern int add_memory(int nid, u64 start, u64 size); +extern int add_virtual_memory(u64 *size); extern int arch_add_memory(int nid, u64 start, u64 size); extern int remove_memory(u64 start, u64 size); extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 02ecb01..76a7cbd 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -931,6 +931,8 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn) #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT) #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT) +#define SECTION_ALIGN(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK) + #ifdef CONFIG_SPARSEMEM /* diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 321fc74..3b38d89 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -29,11 +29,25 @@ #include #include #include +#include #include #include "internal.h" +/* + * online_page_chain contains chain of notifiers called when page is onlined. + * When kernel is booting native_online_page_notifier() is registered with + * priority 0 as default notifier. Custom notifier should be registered with + * pririty > 0. It could be terminal (it should return NOTIFY_STOP on success) + * or not (it should return NOTIFY_DONE or NOTIFY_OK on success; for full list + * of return codes look into include/linux/notifier.h). + * + * Working example of usage: drivers/xen/balloon.c + */ + +static RAW_NOTIFIER_HEAD(online_page_chain); + DEFINE_MUTEX(mem_hotplug_mutex); void lock_memory_hotplug(void) @@ -361,8 +375,33 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, } EXPORT_SYMBOL_GPL(__remove_pages); -void online_page(struct page *page) +int register_online_page_notifier(struct notifier_block *nb) +{ + int rc; + + lock_memory_hotplug(); + rc = raw_notifier_chain_register(&online_page_chain, nb); + unlock_memory_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(register_online_page_notifier); + +int unregister_online_page_notifier(struct notifier_block *nb) +{ + int rc; + + lock_memory_hotplug(); + rc = raw_notifier_chain_unregister(&online_page_chain, nb); + unlock_memory_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(unregister_online_page_notifier); + +static int native_online_page_notifier(struct notifier_block *nb, unsigned long val, void *v) { + struct page *page = v; unsigned long pfn = page_to_pfn(page); totalram_pages++; @@ -375,12 +414,30 @@ void online_page(struct page *page) #endif #ifdef CONFIG_FLATMEM - max_mapnr = max(page_to_pfn(page), max_mapnr); + max_mapnr = max(pfn, max_mapnr); #endif ClearPageReserved(page); init_page_count(page); __free_page(page); + + return NOTIFY_OK; +} + +static struct notifier_block native_online_page_nb = { + .notifier_call = native_online_page_notifier, + .priority = 0 +}; + +static int __init init_online_page_chain(void) +{ + return register_online_page_notifier(&native_online_page_nb); +} +pure_initcall(init_online_page_chain); + +static void online_page(struct page *page) +{ + raw_notifier_call_chain(&online_page_chain, 0, page); } static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, @@ -591,6 +648,36 @@ out: } EXPORT_SYMBOL_GPL(add_memory); +/* + * add_virtual_memory() adds memory region of size >= *size above max_pfn. + * New region is section aligned and size is modified to be multiple of + * section size. Those features allow optimal use of address space and + * establish proper aligment when this function is called first time after + * boot (last section not fully populated at boot time may contains unused + * memory pages with PG_reserved bit not set; online_pages() does not allow + * page onlining in whole section if first page does not have PG_reserved + * bit set). Real size of added memory should be established at page onlining + * stage. + * + * This function is often used in virtual guests because mainly they do not + * care about new memory region address. + * + * Working example of usage: drivers/xen/balloon.c + */ + +int add_virtual_memory(u64 *size) +{ + int nid; + u64 start; + + start = PFN_PHYS(SECTION_ALIGN(max_pfn)); + *size = (((*size >> PAGE_SHIFT) & PAGE_SECTION_MASK) + PAGES_PER_SECTION) << PAGE_SHIFT; + nid = memory_add_physaddr_to_nid(start); + + return add_memory(nid, start, *size); +} +EXPORT_SYMBOL_GPL(add_virtual_memory); + #ifdef CONFIG_MEMORY_HOTREMOVE /* * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy -- 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/