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-rw-r--r--drivers/xen/balloon.c69
-rw-r--r--include/xen/balloon.h3
2 files changed, 69 insertions, 3 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 2a2ef97697b2..a3dc75db135c 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);
@@ -412,7 +416,8 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
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(__get_cpu_var(balloon_scratch_page)),
+ PAGE_KERNEL_RO), 0);
BUG_ON(ret);
}
#endif
@@ -425,7 +430,8 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
/* 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);
+ __set_phys_to_machine(pfn,
+ pfn_to_mfn(page_to_pfn(__get_cpu_var(balloon_scratch_page))));
balloon_append(pfn_to_page(pfn));
}
@@ -480,6 +486,18 @@ 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 +591,47 @@ 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 +668,15 @@ 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");
diff --git a/include/xen/balloon.h b/include/xen/balloon.h
index cc2e1a7e44ec..a4c1c6a93691 100644
--- a/include/xen/balloon.h
+++ b/include/xen/balloon.h
@@ -29,6 +29,9 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages,
bool highmem);
void free_xenballooned_pages(int nr_pages, struct page **pages);
+struct page *get_balloon_scratch_page(void);
+void put_balloon_scratch_page(void);
+
struct device;
#ifdef CONFIG_XEN_SELFBALLOONING
extern int register_xen_selfballooning(struct device *dev);