diff options
Diffstat (limited to 'drivers/xen/balloon.c')
| -rw-r--r-- | drivers/xen/balloon.c | 215 |
1 files changed, 183 insertions, 32 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index f54290b..31ab82f 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -4,6 +4,12 @@ * 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 Citrix 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 @@ -33,6 +39,7 @@ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/errno.h> +#include <linux/module.h> #include <linux/mm.h> #include <linux/bootmem.h> #include <linux/pagemap.h> @@ -40,6 +47,9 @@ #include <linux/mutex.h> #include <linux/list.h> #include <linux/gfp.h> +#include <linux/notifier.h> +#include <linux/memory.h> +#include <linux/memory_hotplug.h> #include <asm/page.h> #include <asm/pgalloc.h> @@ -84,8 +94,8 @@ static unsigned long frame_list[PAGE_SIZE / sizeof(unsigned long)]; #define inc_totalhigh_pages() (totalhigh_pages++) #define dec_totalhigh_pages() (totalhigh_pages--) #else -#define inc_totalhigh_pages() do {} while(0) -#define dec_totalhigh_pages() do {} while(0) +#define inc_totalhigh_pages() do {} while (0) +#define dec_totalhigh_pages() do {} while (0) #endif /* List of ballooned pages, threaded through the mem_map array. */ @@ -145,8 +155,7 @@ static struct page *balloon_retrieve(bool prefer_highmem) if (PageHighMem(page)) { balloon_stats.balloon_high--; inc_totalhigh_pages(); - } - else + } else balloon_stats.balloon_low--; totalram_pages++; @@ -194,6 +203,87 @@ static enum bp_state update_schedule(enum bp_state state) return BP_EAGAIN; } +#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 bool balloon_is_inflated(void) +{ + if (balloon_stats.balloon_low || balloon_stats.balloon_high || + balloon_stats.balloon_hotplug) + return true; + else + return false; +} + +/* + * reserve_additional_memory() adds memory region of size >= credit 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 alignment when this function is called first time after + * boot (last section not fully populated at boot time contains unused memory + * pages with PG_reserved bit not set; online_pages_range() does not allow page + * onlining in whole range if first onlined page does not have PG_reserved + * bit set). Real size of added memory is established at page onlining stage. + */ + +static enum bp_state reserve_additional_memory(long credit) +{ + int nid, rc; + u64 hotplug_start_paddr; + unsigned long balloon_hotplug = credit; + + hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); + balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); + nid = memory_add_physaddr_to_nid(hotplug_start_paddr); + + rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); + + if (rc) { + pr_info("xen_balloon: %s: add_memory() failed: %i\n", __func__, rc); + return BP_EAGAIN; + } + + balloon_hotplug -= credit; + + balloon_stats.hotplug_pages += credit; + balloon_stats.balloon_hotplug = balloon_hotplug; + + return BP_DONE; +} + +static void xen_online_page(struct page *page) +{ + __online_page_set_limits(page); + + 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); +} + +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; @@ -206,6 +296,21 @@ static long current_credit(void) return target - balloon_stats.current_pages; } +static bool balloon_is_inflated(void) +{ + if (balloon_stats.balloon_low || balloon_stats.balloon_high) + return true; + else + return false; +} + +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; @@ -217,6 +322,15 @@ 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); @@ -279,6 +393,15 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) .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); @@ -299,7 +422,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) (unsigned long)__va(pfn << PAGE_SHIFT), __pte_ma(0), 0); BUG_ON(ret); - } + } } @@ -340,8 +463,12 @@ static void balloon_process(struct work_struct *work) do { 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, GFP_BALLOON); @@ -374,20 +501,24 @@ EXPORT_SYMBOL_GPL(balloon_set_new_target); * alloc_xenballooned_pages - get pages that have been ballooned out * @nr_pages: Number of pages to get * @pages: pages returned + * @highmem: allow highmem pages * @return 0 on success, error otherwise */ -int alloc_xenballooned_pages(int nr_pages, struct page** pages) +int alloc_xenballooned_pages(int nr_pages, struct page **pages, bool highmem) { int pgno = 0; - struct page* page; + struct page *page; mutex_lock(&balloon_mutex); while (pgno < nr_pages) { - page = balloon_retrieve(true); - if (page) { + page = balloon_retrieve(highmem); + if (page && (highmem || !PageHighMem(page))) { pages[pgno++] = page; } else { enum bp_state st; - st = decrease_reservation(nr_pages - pgno, GFP_HIGHUSER); + if (page) + balloon_append(page); + st = decrease_reservation(nr_pages - pgno, + highmem ? GFP_HIGHUSER : GFP_USER); if (st != BP_DONE) goto out_undo; } @@ -409,7 +540,7 @@ EXPORT_SYMBOL(alloc_xenballooned_pages); * @nr_pages: Number of pages * @pages: pages to return */ -void free_xenballooned_pages(int nr_pages, struct page** pages) +void free_xenballooned_pages(int nr_pages, struct page **pages) { int i; @@ -428,17 +559,40 @@ void free_xenballooned_pages(int nr_pages, struct page** pages) } EXPORT_SYMBOL(free_xenballooned_pages); -static int __init balloon_init(void) +static void __init balloon_add_region(unsigned long start_pfn, + unsigned long pages) { unsigned long pfn, extra_pfn_end; struct page *page; + /* + * If the amount of usable memory has been limited (e.g., with + * the 'mem' command line parameter), don't add pages beyond + * this limit. + */ + extra_pfn_end = min(max_pfn, start_pfn + pages); + + for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { + page = pfn_to_page(pfn); + /* totalram_pages and totalhigh_pages do not + include the boot-time balloon extension, so + don't subtract from it. */ + __balloon_append(page); + } +} + +static int __init balloon_init(void) +{ + int i; + if (!xen_domain()) return -ENODEV; pr_info("xen/balloon: Initialising balloon driver.\n"); - balloon_stats.current_pages = xen_pv_domain() ? min(xen_start_info->nr_pages, max_pfn) : max_pfn; + balloon_stats.current_pages = xen_pv_domain() + ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) + : max_pfn; balloon_stats.target_pages = balloon_stats.current_pages; balloon_stats.balloon_low = 0; balloon_stats.balloon_high = 0; @@ -448,25 +602,22 @@ static int __init balloon_init(void) balloon_stats.retry_count = 1; balloon_stats.max_retry_count = RETRY_UNLIMITED; +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG + balloon_stats.hotplug_pages = 0; + balloon_stats.balloon_hotplug = 0; + + set_online_page_callback(&xen_online_page); + register_memory_notifier(&xen_memory_nb); +#endif + /* - * Initialise the balloon with excess memory space. We need - * to make sure we don't add memory which doesn't exist or - * logically exist. The E820 map can be trimmed to be smaller - * than the amount of physical memory due to the mem= command - * line parameter. And if this is a 32-bit non-HIGHMEM kernel - * on a system with memory which requires highmem to access, - * don't try to use it. + * Initialize the balloon with pages from the extra memory + * regions (see arch/x86/xen/setup.c). */ - extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()), - (unsigned long)PFN_DOWN(xen_extra_mem_start + xen_extra_mem_size)); - for (pfn = PFN_UP(xen_extra_mem_start); - pfn < extra_pfn_end; - pfn++) { - page = pfn_to_page(pfn); - /* totalram_pages and totalhigh_pages do not include the boot-time - balloon extension, so don't subtract from it. */ - __balloon_append(page); - } + for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) + if (xen_extra_mem[i].size) + balloon_add_region(PFN_UP(xen_extra_mem[i].start), + PFN_DOWN(xen_extra_mem[i].size)); return 0; } |