The patch titled mm: extend memory hotplug API to allow memory hotplug in virtual machines has been added to the -mm tree. Its filename is mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: mm: extend memory hotplug API to allow memory hotplug in virtual machines From: Daniel Kiper <dkiper@xxxxxxxxxxxx> This patch contains online_page_callback and apropriate functions for registering/unregistering online page callbacks. It allows to do some machine specific tasks during online page stage which is required to implement memory hotplug in virtual machines. Currently this patch is required by latest memory hotplug support for Xen balloon driver patch which will be posted soon. Additionally, originial online_page() function was splited into following functions doing "atomic" operations: - __online_page_set_limits() - set new limits for memory management code, - __online_page_increment_counters() - increment totalram_pages and totalhigh_pages, - __online_page_free() - free page to allocator. It was done to: - not duplicate existing code, - ease hotplug code devolpment by usage of well defined interface, - avoid stupid bugs which are unavoidable when the same code (by design) is developed in many places. Signed-off-by: Daniel Kiper <dkiper@xxxxxxxxxxxx> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx> Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/memory_hotplug.h | 11 ++++- mm/memory_hotplug.c | 68 +++++++++++++++++++++++++++++-- 2 files changed, 74 insertions(+), 5 deletions(-) diff -puN include/linux/memory_hotplug.h~mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines include/linux/memory_hotplug.h --- a/include/linux/memory_hotplug.h~mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines +++ a/include/linux/memory_hotplug.h @@ -68,12 +68,19 @@ static inline void zone_seqlock_init(str 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); +typedef void (*online_page_callback_t)(struct page *page); + +extern int set_online_page_callback(online_page_callback_t callback); +extern int restore_online_page_callback(online_page_callback_t callback); + +extern void __online_page_set_limits(struct page *page); +extern void __online_page_increment_counters(struct page *page); +extern void __online_page_free(struct page *page); + #ifdef CONFIG_MEMORY_HOTREMOVE extern bool is_pageblock_removable_nolock(struct page *page); #endif /* CONFIG_MEMORY_HOTREMOVE */ diff -puN mm/memory_hotplug.c~mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines mm/memory_hotplug.c --- a/mm/memory_hotplug.c~mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines +++ a/mm/memory_hotplug.c @@ -34,6 +34,17 @@ #include "internal.h" +/* + * online_page_callback contains pointer to current page onlining function. + * Initially it is generic_online_page(). If it is required it could be + * changed by calling set_online_page_callback() for callback registration + * and restore_online_page_callback() for generic callback restore. + */ + +static void generic_online_page(struct page *page); + +static online_page_callback_t online_page_callback = generic_online_page; + DEFINE_MUTEX(mem_hotplug_mutex); void lock_memory_hotplug(void) @@ -361,23 +372,74 @@ int __remove_pages(struct zone *zone, un } EXPORT_SYMBOL_GPL(__remove_pages); -void online_page(struct page *page) +int set_online_page_callback(online_page_callback_t callback) +{ + int rc = -EINVAL; + + lock_memory_hotplug(); + + if (online_page_callback == generic_online_page) { + online_page_callback = callback; + rc = 0; + } + + unlock_memory_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(set_online_page_callback); + +int restore_online_page_callback(online_page_callback_t callback) +{ + int rc = -EINVAL; + + lock_memory_hotplug(); + + if (online_page_callback == callback) { + online_page_callback = generic_online_page; + rc = 0; + } + + unlock_memory_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(restore_online_page_callback); + +void __online_page_set_limits(struct page *page) { unsigned long pfn = page_to_pfn(page); - totalram_pages++; if (pfn >= num_physpages) num_physpages = pfn + 1; +} +EXPORT_SYMBOL_GPL(__online_page_set_limits); + +void __online_page_increment_counters(struct page *page) +{ + totalram_pages++; #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) totalhigh_pages++; #endif +} +EXPORT_SYMBOL_GPL(__online_page_increment_counters); +void __online_page_free(struct page *page) +{ ClearPageReserved(page); init_page_count(page); __free_page(page); } +EXPORT_SYMBOL_GPL(__online_page_free); + +static void generic_online_page(struct page *page) +{ + __online_page_set_limits(page); + __online_page_increment_counters(page); + __online_page_free(page); +} static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) @@ -388,7 +450,7 @@ static int online_pages_range(unsigned l if (PageReserved(pfn_to_page(start_pfn))) for (i = 0; i < nr_pages; i++) { page = pfn_to_page(start_pfn + i); - online_page(page); + online_page_callback(page); onlined_pages++; } *(unsigned long *)arg = onlined_pages; _ Patches currently in -mm which might be from dkiper@xxxxxxxxxxxx are mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines.patch mm-extend-memory-hotplug-api-to-allow-memory-hotplug-in-virtual-machines-fix.patch xen-balloon-memory-hotplug-support-for-xen-balloon-driver.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html