* 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
#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>
#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>
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;
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;
.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);
.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);
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);
* alloc_xenballooned_pages - get pages that have been ballooned out
* @nr_pages: Number of pages to get
* @pages: pages returned
+ * @highmem: highmem or lowmem 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;
mutex_lock(&balloon_mutex);
while (pgno < nr_pages) {
- page = balloon_retrieve(true);
- if (page) {
+ page = balloon_retrieve(highmem);
+ if (page && PageHighMem(page) == highmem) {
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;
}
}
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;
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;
}
git.openpandora.org / pandora-kernel.git / blobdiff