diff options
Diffstat (limited to 'drivers/xen/balloon.c')
| -rw-r--r-- | drivers/xen/balloon.c | 90 |
1 files changed, 79 insertions, 11 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 2a2ef97697b..b232908a619 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -38,6 +38,7 @@ #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt +#include <linux/cpu.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/errno.h> @@ -52,6 +53,7 @@ #include <linux/notifier.h> #include <linux/memory.h> #include <linux/memory_hotplug.h> +#include <linux/percpu-defs.h> #include <asm/page.h> #include <asm/pgalloc.h> @@ -90,6 +92,8 @@ EXPORT_SYMBOL_GPL(balloon_stats); /* We increase/decrease in batches which fit in a page */ static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; +static DEFINE_PER_CPU(struct page *, balloon_scratch_page); + /* List of ballooned pages, threaded through the mem_map array. */ static LIST_HEAD(ballooned_pages); @@ -345,8 +349,6 @@ static enum bp_state increase_reservation(unsigned long nr_pages) BUG_ON(page == NULL); pfn = page_to_pfn(page); - BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && - phys_to_machine_mapping_valid(pfn)); set_phys_to_machine(pfn, frame_list[i]); @@ -376,6 +378,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) enum bp_state state = BP_DONE; unsigned long pfn, i; struct page *page; + struct page *scratch_page; int ret; struct xen_memory_reservation reservation = { .address_bits = 0, @@ -408,27 +411,35 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) scrub_page(page); + /* + * Ballooned out frames are effectively replaced with + * a scratch frame. Ensure direct mappings and the + * p2m are consistent. + */ + scratch_page = get_balloon_scratch_page(); #ifdef CONFIG_XEN_HAVE_PVMMU if (xen_pv_domain() && !PageHighMem(page)) { ret = HYPERVISOR_update_va_mapping( (unsigned long)__va(pfn << PAGE_SHIFT), - __pte_ma(0), 0); + pfn_pte(page_to_pfn(scratch_page), + PAGE_KERNEL_RO), 0); BUG_ON(ret); } #endif + if (!xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long p; + p = page_to_pfn(scratch_page); + __set_phys_to_machine(pfn, pfn_to_mfn(p)); + } + put_balloon_scratch_page(); + + balloon_append(pfn_to_page(pfn)); } /* Ensure that ballooned highmem pages don't have kmaps. */ kmap_flush_unused(); flush_tlb_all(); - /* No more mappings: invalidate P2M and add to balloon. */ - for (i = 0; i < nr_pages; i++) { - pfn = mfn_to_pfn(frame_list[i]); - __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); - balloon_append(pfn_to_page(pfn)); - } - set_xen_guest_handle(reservation.extent_start, frame_list); reservation.nr_extents = nr_pages; ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); @@ -480,6 +491,18 @@ static void balloon_process(struct work_struct *work) mutex_unlock(&balloon_mutex); } +struct page *get_balloon_scratch_page(void) +{ + struct page *ret = get_cpu_var(balloon_scratch_page); + BUG_ON(ret == NULL); + return ret; +} + +void put_balloon_scratch_page(void) +{ + put_cpu_var(balloon_scratch_page); +} + /* Resets the Xen limit, sets new target, and kicks off processing. */ void balloon_set_new_target(unsigned long target) { @@ -573,13 +596,47 @@ static void __init balloon_add_region(unsigned long start_pfn, } } +static int __cpuinit balloon_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + int cpu = (long)hcpu; + switch (action) { + case CPU_UP_PREPARE: + if (per_cpu(balloon_scratch_page, cpu) != NULL) + break; + per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL); + if (per_cpu(balloon_scratch_page, cpu) == NULL) { + pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu); + return NOTIFY_BAD; + } + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block balloon_cpu_notifier __cpuinitdata = { + .notifier_call = balloon_cpu_notify, +}; + static int __init balloon_init(void) { - int i; + int i, cpu; if (!xen_domain()) return -ENODEV; + for_each_online_cpu(cpu) + { + per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL); + if (per_cpu(balloon_scratch_page, cpu) == NULL) { + pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu); + return -ENOMEM; + } + } + register_cpu_notifier(&balloon_cpu_notifier); + pr_info("Initialising balloon driver\n"); balloon_stats.current_pages = xen_pv_domain() @@ -616,4 +673,15 @@ static int __init balloon_init(void) subsys_initcall(balloon_init); +static int __init balloon_clear(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + per_cpu(balloon_scratch_page, cpu) = NULL; + + return 0; +} +early_initcall(balloon_clear); + MODULE_LICENSE("GPL"); |