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![Oleksandr Tyshchenko](/assets/img/avatar_default.png)
This patch rolls back some of the changes introduced by commit
121f2faca2
"xen/balloon: rename alloc/free_xenballooned_pages"
in order to make possible to still allocate xenballooned pages
if CONFIG_XEN_UNPOPULATED_ALLOC is enabled.
On Arm the unpopulated pages will be allocated on top of extended
regions provided by Xen via device-tree (the subsequent patches
will add required bits to support unpopulated-alloc feature on Arm).
The problem is that extended regions feature has been introduced
into Xen quite recently (during 4.16 release cycle). So this
effectively means that Linux must only use unpopulated-alloc on Arm
if it is running on "new Xen" which advertises these regions.
But, it will only be known after parsing the "hypervisor" node
at boot time, so before doing that we cannot assume anything.
In order to keep working if CONFIG_XEN_UNPOPULATED_ALLOC is enabled
and the extended regions are not advertised (Linux is running on
"old Xen", etc) we need the fallback to alloc_xenballooned_pages().
This way we wouldn't reduce the amount of memory usable (wasting
RAM pages) for any of the external mappings anymore (and eliminate
XSA-300) with "new Xen", but would be still functional ballooning
out RAM pages with "old Xen".
Also rename alloc(free)_xenballooned_pages to xen_alloc(free)_ballooned_pages
and make xen_alloc(free)_unpopulated_pages static inline in xen.h
if CONFIG_XEN_UNPOPULATED_ALLOC is disabled.
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/1639080336-26573-4-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
808 lines
20 KiB
C
808 lines
20 KiB
C
/******************************************************************************
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* Xen balloon driver - enables returning/claiming memory to/from Xen.
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*
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* Copyright (c) 2003, B Dragovic
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* Copyright (c) 2003-2004, M Williamson, K Fraser
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* Copyright (c) 2005 Dan M. Smith, IBM Corporation
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* Copyright (c) 2010 Daniel Kiper
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*
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* Memory hotplug support was written by Daniel Kiper. Work on
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* it was sponsored by Google under Google Summer of Code 2010
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* program. Jeremy Fitzhardinge from Citrix was the mentor for
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* this project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
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#include <linux/cpu.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/cred.h>
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#include <linux/errno.h>
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#include <linux/freezer.h>
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#include <linux/kthread.h>
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#include <linux/mm.h>
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#include <linux/memblock.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/mutex.h>
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#include <linux/list.h>
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#include <linux/gfp.h>
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#include <linux/notifier.h>
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#include <linux/memory.h>
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#include <linux/memory_hotplug.h>
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#include <linux/percpu-defs.h>
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#include <linux/slab.h>
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#include <linux/sysctl.h>
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#include <linux/moduleparam.h>
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#include <asm/page.h>
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#include <asm/tlb.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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#include <xen/xen.h>
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#include <xen/interface/xen.h>
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#include <xen/interface/memory.h>
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#include <xen/balloon.h>
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#include <xen/features.h>
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#include <xen/page.h>
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#include <xen/mem-reservation.h>
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#undef MODULE_PARAM_PREFIX
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#define MODULE_PARAM_PREFIX "xen."
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static uint __read_mostly balloon_boot_timeout = 180;
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module_param(balloon_boot_timeout, uint, 0444);
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#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
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static int xen_hotplug_unpopulated;
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static struct ctl_table balloon_table[] = {
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{
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.procname = "hotplug_unpopulated",
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.data = &xen_hotplug_unpopulated,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_ONE,
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},
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{ }
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};
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static struct ctl_table balloon_root[] = {
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{
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.procname = "balloon",
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.mode = 0555,
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.child = balloon_table,
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},
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{ }
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};
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static struct ctl_table xen_root[] = {
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{
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.procname = "xen",
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.mode = 0555,
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.child = balloon_root,
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},
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{ }
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};
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#else
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#define xen_hotplug_unpopulated 0
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#endif
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/*
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* Use one extent per PAGE_SIZE to avoid to break down the page into
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* multiple frame.
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*/
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#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
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/*
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* balloon_thread() state:
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*
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* BP_DONE: done or nothing to do,
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* BP_WAIT: wait to be rescheduled,
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* BP_EAGAIN: error, go to sleep,
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* BP_ECANCELED: error, balloon operation canceled.
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*/
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static enum bp_state {
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BP_DONE,
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BP_WAIT,
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BP_EAGAIN,
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BP_ECANCELED
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} balloon_state = BP_DONE;
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/* Main waiting point for xen-balloon thread. */
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static DECLARE_WAIT_QUEUE_HEAD(balloon_thread_wq);
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static DEFINE_MUTEX(balloon_mutex);
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struct balloon_stats balloon_stats;
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EXPORT_SYMBOL_GPL(balloon_stats);
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/* We increase/decrease in batches which fit in a page */
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static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)];
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/* List of ballooned pages, threaded through the mem_map array. */
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static LIST_HEAD(ballooned_pages);
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static DECLARE_WAIT_QUEUE_HEAD(balloon_wq);
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/* When ballooning out (allocating memory to return to Xen) we don't really
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want the kernel to try too hard since that can trigger the oom killer. */
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#define GFP_BALLOON \
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(GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC)
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/* balloon_append: add the given page to the balloon. */
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static void balloon_append(struct page *page)
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{
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__SetPageOffline(page);
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/* Lowmem is re-populated first, so highmem pages go at list tail. */
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if (PageHighMem(page)) {
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list_add_tail(&page->lru, &ballooned_pages);
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balloon_stats.balloon_high++;
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} else {
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list_add(&page->lru, &ballooned_pages);
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balloon_stats.balloon_low++;
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}
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wake_up(&balloon_wq);
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}
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/* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
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static struct page *balloon_retrieve(bool require_lowmem)
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{
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struct page *page;
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if (list_empty(&ballooned_pages))
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return NULL;
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page = list_entry(ballooned_pages.next, struct page, lru);
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if (require_lowmem && PageHighMem(page))
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return NULL;
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list_del(&page->lru);
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if (PageHighMem(page))
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balloon_stats.balloon_high--;
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else
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balloon_stats.balloon_low--;
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__ClearPageOffline(page);
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return page;
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}
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static struct page *balloon_next_page(struct page *page)
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{
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struct list_head *next = page->lru.next;
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if (next == &ballooned_pages)
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return NULL;
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return list_entry(next, struct page, lru);
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}
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static void update_schedule(void)
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{
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if (balloon_state == BP_WAIT || balloon_state == BP_ECANCELED)
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return;
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if (balloon_state == BP_DONE) {
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balloon_stats.schedule_delay = 1;
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balloon_stats.retry_count = 1;
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return;
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}
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++balloon_stats.retry_count;
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if (balloon_stats.max_retry_count != RETRY_UNLIMITED &&
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balloon_stats.retry_count > balloon_stats.max_retry_count) {
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balloon_stats.schedule_delay = 1;
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balloon_stats.retry_count = 1;
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balloon_state = BP_ECANCELED;
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return;
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}
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balloon_stats.schedule_delay <<= 1;
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if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay)
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balloon_stats.schedule_delay = balloon_stats.max_schedule_delay;
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balloon_state = BP_EAGAIN;
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}
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#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
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static void release_memory_resource(struct resource *resource)
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{
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if (!resource)
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return;
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/*
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* No need to reset region to identity mapped since we now
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* know that no I/O can be in this region
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*/
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release_resource(resource);
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kfree(resource);
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}
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static struct resource *additional_memory_resource(phys_addr_t size)
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{
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struct resource *res;
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int ret;
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res = kzalloc(sizeof(*res), GFP_KERNEL);
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if (!res)
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return NULL;
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res->name = "System RAM";
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res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
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ret = allocate_resource(&iomem_resource, res,
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size, 0, -1,
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PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
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if (ret < 0) {
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pr_err("Cannot allocate new System RAM resource\n");
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kfree(res);
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return NULL;
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}
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return res;
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}
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static enum bp_state reserve_additional_memory(void)
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{
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long credit;
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struct resource *resource;
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int nid, rc;
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unsigned long balloon_hotplug;
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credit = balloon_stats.target_pages + balloon_stats.target_unpopulated
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- balloon_stats.total_pages;
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/*
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* Already hotplugged enough pages? Wait for them to be
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* onlined.
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*/
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if (credit <= 0)
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return BP_WAIT;
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balloon_hotplug = round_up(credit, PAGES_PER_SECTION);
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resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE);
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if (!resource)
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goto err;
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nid = memory_add_physaddr_to_nid(resource->start);
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#ifdef CONFIG_XEN_HAVE_PVMMU
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/*
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* We don't support PV MMU when Linux and Xen is using
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* different page granularity.
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*/
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BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
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/*
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* add_memory() will build page tables for the new memory so
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* the p2m must contain invalid entries so the correct
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* non-present PTEs will be written.
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*
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* If a failure occurs, the original (identity) p2m entries
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* are not restored since this region is now known not to
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* conflict with any devices.
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*/
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if (!xen_feature(XENFEAT_auto_translated_physmap)) {
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unsigned long pfn, i;
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pfn = PFN_DOWN(resource->start);
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for (i = 0; i < balloon_hotplug; i++) {
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if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
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pr_warn("set_phys_to_machine() failed, no memory added\n");
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goto err;
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}
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}
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}
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#endif
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/*
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* add_memory_resource() will call online_pages() which in its turn
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* will call xen_online_page() callback causing deadlock if we don't
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* release balloon_mutex here. Unlocking here is safe because the
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* callers drop the mutex before trying again.
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*/
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mutex_unlock(&balloon_mutex);
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/* add_memory_resource() requires the device_hotplug lock */
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lock_device_hotplug();
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rc = add_memory_resource(nid, resource, MHP_MERGE_RESOURCE);
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unlock_device_hotplug();
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mutex_lock(&balloon_mutex);
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if (rc) {
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pr_warn("Cannot add additional memory (%i)\n", rc);
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goto err;
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}
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balloon_stats.total_pages += balloon_hotplug;
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return BP_WAIT;
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err:
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release_memory_resource(resource);
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return BP_ECANCELED;
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}
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static void xen_online_page(struct page *page, unsigned int order)
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{
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unsigned long i, size = (1 << order);
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unsigned long start_pfn = page_to_pfn(page);
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struct page *p;
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pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);
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mutex_lock(&balloon_mutex);
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for (i = 0; i < size; i++) {
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p = pfn_to_page(start_pfn + i);
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balloon_append(p);
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}
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mutex_unlock(&balloon_mutex);
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}
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static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v)
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{
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if (val == MEM_ONLINE)
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wake_up(&balloon_thread_wq);
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return NOTIFY_OK;
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}
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static struct notifier_block xen_memory_nb = {
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.notifier_call = xen_memory_notifier,
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.priority = 0
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};
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#else
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static enum bp_state reserve_additional_memory(void)
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{
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balloon_stats.target_pages = balloon_stats.current_pages +
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balloon_stats.target_unpopulated;
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return BP_ECANCELED;
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}
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#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
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static long current_credit(void)
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{
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return balloon_stats.target_pages - balloon_stats.current_pages;
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}
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static bool balloon_is_inflated(void)
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{
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return balloon_stats.balloon_low || balloon_stats.balloon_high;
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}
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static enum bp_state increase_reservation(unsigned long nr_pages)
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{
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int rc;
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unsigned long i;
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struct page *page;
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if (nr_pages > ARRAY_SIZE(frame_list))
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nr_pages = ARRAY_SIZE(frame_list);
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page = list_first_entry_or_null(&ballooned_pages, struct page, lru);
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for (i = 0; i < nr_pages; i++) {
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if (!page) {
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nr_pages = i;
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break;
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}
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frame_list[i] = page_to_xen_pfn(page);
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page = balloon_next_page(page);
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}
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rc = xenmem_reservation_increase(nr_pages, frame_list);
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if (rc <= 0)
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return BP_EAGAIN;
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for (i = 0; i < rc; i++) {
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page = balloon_retrieve(false);
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BUG_ON(page == NULL);
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xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]);
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/* Relinquish the page back to the allocator. */
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free_reserved_page(page);
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}
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balloon_stats.current_pages += rc;
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return BP_DONE;
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}
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static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
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{
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enum bp_state state = BP_DONE;
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unsigned long i;
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struct page *page, *tmp;
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int ret;
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LIST_HEAD(pages);
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if (nr_pages > ARRAY_SIZE(frame_list))
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nr_pages = ARRAY_SIZE(frame_list);
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for (i = 0; i < nr_pages; i++) {
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page = alloc_page(gfp);
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if (page == NULL) {
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nr_pages = i;
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state = BP_EAGAIN;
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break;
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}
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adjust_managed_page_count(page, -1);
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xenmem_reservation_scrub_page(page);
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list_add(&page->lru, &pages);
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}
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/*
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* Ensure that ballooned highmem pages don't have kmaps.
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*
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* Do this before changing the p2m as kmap_flush_unused()
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* reads PTEs to obtain pages (and hence needs the original
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* p2m entry).
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*/
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kmap_flush_unused();
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/*
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* Setup the frame, update direct mapping, invalidate P2M,
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* and add to balloon.
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*/
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i = 0;
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list_for_each_entry_safe(page, tmp, &pages, lru) {
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frame_list[i++] = xen_page_to_gfn(page);
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xenmem_reservation_va_mapping_reset(1, &page);
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list_del(&page->lru);
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balloon_append(page);
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}
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flush_tlb_all();
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ret = xenmem_reservation_decrease(nr_pages, frame_list);
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BUG_ON(ret != nr_pages);
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balloon_stats.current_pages -= nr_pages;
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return state;
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}
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/*
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* Stop waiting if either state is BP_DONE and ballooning action is
|
|
* needed, or if the credit has changed while state is not BP_DONE.
|
|
*/
|
|
static bool balloon_thread_cond(long credit)
|
|
{
|
|
if (balloon_state == BP_DONE)
|
|
credit = 0;
|
|
|
|
return current_credit() != credit || kthread_should_stop();
|
|
}
|
|
|
|
/*
|
|
* As this is a kthread it is guaranteed to run as a single instance only.
|
|
* We may of course race updates of the target counts (which are protected
|
|
* by the balloon lock), or with changes to the Xen hard limit, but we will
|
|
* recover from these in time.
|
|
*/
|
|
static int balloon_thread(void *unused)
|
|
{
|
|
long credit;
|
|
unsigned long timeout;
|
|
|
|
set_freezable();
|
|
for (;;) {
|
|
switch (balloon_state) {
|
|
case BP_DONE:
|
|
case BP_ECANCELED:
|
|
timeout = 3600 * HZ;
|
|
break;
|
|
case BP_EAGAIN:
|
|
timeout = balloon_stats.schedule_delay * HZ;
|
|
break;
|
|
case BP_WAIT:
|
|
timeout = HZ;
|
|
break;
|
|
}
|
|
|
|
credit = current_credit();
|
|
|
|
wait_event_freezable_timeout(balloon_thread_wq,
|
|
balloon_thread_cond(credit), timeout);
|
|
|
|
if (kthread_should_stop())
|
|
return 0;
|
|
|
|
mutex_lock(&balloon_mutex);
|
|
|
|
credit = current_credit();
|
|
|
|
if (credit > 0) {
|
|
if (balloon_is_inflated())
|
|
balloon_state = increase_reservation(credit);
|
|
else
|
|
balloon_state = reserve_additional_memory();
|
|
}
|
|
|
|
if (credit < 0) {
|
|
long n_pages;
|
|
|
|
n_pages = min(-credit, si_mem_available());
|
|
balloon_state = decrease_reservation(n_pages,
|
|
GFP_BALLOON);
|
|
if (balloon_state == BP_DONE && n_pages != -credit &&
|
|
n_pages < totalreserve_pages)
|
|
balloon_state = BP_EAGAIN;
|
|
}
|
|
|
|
update_schedule();
|
|
|
|
mutex_unlock(&balloon_mutex);
|
|
|
|
cond_resched();
|
|
}
|
|
}
|
|
|
|
/* Resets the Xen limit, sets new target, and kicks off processing. */
|
|
void balloon_set_new_target(unsigned long target)
|
|
{
|
|
/* No need for lock. Not read-modify-write updates. */
|
|
balloon_stats.target_pages = target;
|
|
wake_up(&balloon_thread_wq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(balloon_set_new_target);
|
|
|
|
static int add_ballooned_pages(unsigned int nr_pages)
|
|
{
|
|
enum bp_state st;
|
|
|
|
if (xen_hotplug_unpopulated) {
|
|
st = reserve_additional_memory();
|
|
if (st != BP_ECANCELED) {
|
|
int rc;
|
|
|
|
mutex_unlock(&balloon_mutex);
|
|
rc = wait_event_interruptible(balloon_wq,
|
|
!list_empty(&ballooned_pages));
|
|
mutex_lock(&balloon_mutex);
|
|
return rc ? -ENOMEM : 0;
|
|
}
|
|
}
|
|
|
|
if (si_mem_available() < nr_pages)
|
|
return -ENOMEM;
|
|
|
|
st = decrease_reservation(nr_pages, GFP_USER);
|
|
if (st != BP_DONE)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* xen_alloc_ballooned_pages - get pages that have been ballooned out
|
|
* @nr_pages: Number of pages to get
|
|
* @pages: pages returned
|
|
* @return 0 on success, error otherwise
|
|
*/
|
|
int xen_alloc_ballooned_pages(unsigned int nr_pages, struct page **pages)
|
|
{
|
|
unsigned int pgno = 0;
|
|
struct page *page;
|
|
int ret;
|
|
|
|
mutex_lock(&balloon_mutex);
|
|
|
|
balloon_stats.target_unpopulated += nr_pages;
|
|
|
|
while (pgno < nr_pages) {
|
|
page = balloon_retrieve(true);
|
|
if (page) {
|
|
pages[pgno++] = page;
|
|
#ifdef CONFIG_XEN_HAVE_PVMMU
|
|
/*
|
|
* We don't support PV MMU when Linux and Xen is using
|
|
* different page granularity.
|
|
*/
|
|
BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
|
|
|
|
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
|
|
ret = xen_alloc_p2m_entry(page_to_pfn(page));
|
|
if (ret < 0)
|
|
goto out_undo;
|
|
}
|
|
#endif
|
|
} else {
|
|
ret = add_ballooned_pages(nr_pages - pgno);
|
|
if (ret < 0)
|
|
goto out_undo;
|
|
}
|
|
}
|
|
mutex_unlock(&balloon_mutex);
|
|
return 0;
|
|
out_undo:
|
|
mutex_unlock(&balloon_mutex);
|
|
xen_free_ballooned_pages(pgno, pages);
|
|
/*
|
|
* NB: xen_free_ballooned_pages will only subtract pgno pages, but since
|
|
* target_unpopulated is incremented with nr_pages at the start we need
|
|
* to remove the remaining ones also, or accounting will be screwed.
|
|
*/
|
|
balloon_stats.target_unpopulated -= nr_pages - pgno;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(xen_alloc_ballooned_pages);
|
|
|
|
/**
|
|
* xen_free_ballooned_pages - return pages retrieved with get_ballooned_pages
|
|
* @nr_pages: Number of pages
|
|
* @pages: pages to return
|
|
*/
|
|
void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages)
|
|
{
|
|
unsigned int i;
|
|
|
|
mutex_lock(&balloon_mutex);
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
if (pages[i])
|
|
balloon_append(pages[i]);
|
|
}
|
|
|
|
balloon_stats.target_unpopulated -= nr_pages;
|
|
|
|
/* The balloon may be too large now. Shrink it if needed. */
|
|
if (current_credit())
|
|
wake_up(&balloon_thread_wq);
|
|
|
|
mutex_unlock(&balloon_mutex);
|
|
}
|
|
EXPORT_SYMBOL(xen_free_ballooned_pages);
|
|
|
|
#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)
|
|
static void __init balloon_add_region(unsigned long start_pfn,
|
|
unsigned long pages)
|
|
{
|
|
unsigned long pfn, extra_pfn_end;
|
|
|
|
/*
|
|
* 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++) {
|
|
/* totalram_pages and totalhigh_pages do not
|
|
include the boot-time balloon extension, so
|
|
don't subtract from it. */
|
|
balloon_append(pfn_to_page(pfn));
|
|
}
|
|
|
|
balloon_stats.total_pages += extra_pfn_end - start_pfn;
|
|
}
|
|
#endif
|
|
|
|
static int __init balloon_init(void)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
pr_info("Initialising balloon driver\n");
|
|
|
|
#ifdef CONFIG_XEN_PV
|
|
balloon_stats.current_pages = xen_pv_domain()
|
|
? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
|
|
: get_num_physpages();
|
|
#else
|
|
balloon_stats.current_pages = get_num_physpages();
|
|
#endif
|
|
balloon_stats.target_pages = balloon_stats.current_pages;
|
|
balloon_stats.balloon_low = 0;
|
|
balloon_stats.balloon_high = 0;
|
|
balloon_stats.total_pages = balloon_stats.current_pages;
|
|
|
|
balloon_stats.schedule_delay = 1;
|
|
balloon_stats.max_schedule_delay = 32;
|
|
balloon_stats.retry_count = 1;
|
|
balloon_stats.max_retry_count = 4;
|
|
|
|
#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
|
|
set_online_page_callback(&xen_online_page);
|
|
register_memory_notifier(&xen_memory_nb);
|
|
register_sysctl_table(xen_root);
|
|
#endif
|
|
|
|
#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)
|
|
{
|
|
int i;
|
|
|
|
/*
|
|
* Initialize the balloon with pages from the extra memory
|
|
* regions (see arch/x86/xen/setup.c).
|
|
*/
|
|
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++)
|
|
if (xen_extra_mem[i].n_pfns)
|
|
balloon_add_region(xen_extra_mem[i].start_pfn,
|
|
xen_extra_mem[i].n_pfns);
|
|
}
|
|
#endif
|
|
|
|
task = kthread_run(balloon_thread, NULL, "xen-balloon");
|
|
if (IS_ERR(task)) {
|
|
pr_err("xen-balloon thread could not be started, ballooning will not work!\n");
|
|
return PTR_ERR(task);
|
|
}
|
|
|
|
/* Init the xen-balloon driver. */
|
|
xen_balloon_init();
|
|
|
|
return 0;
|
|
}
|
|
subsys_initcall(balloon_init);
|
|
|
|
static int __init balloon_wait_finish(void)
|
|
{
|
|
long credit, last_credit = 0;
|
|
unsigned long last_changed = 0;
|
|
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
/* PV guests don't need to wait. */
|
|
if (xen_pv_domain() || !current_credit())
|
|
return 0;
|
|
|
|
pr_notice("Waiting for initial ballooning down having finished.\n");
|
|
|
|
while ((credit = current_credit()) < 0) {
|
|
if (credit != last_credit) {
|
|
last_changed = jiffies;
|
|
last_credit = credit;
|
|
}
|
|
if (balloon_state == BP_ECANCELED) {
|
|
pr_warn_once("Initial ballooning failed, %ld pages need to be freed.\n",
|
|
-credit);
|
|
if (jiffies - last_changed >= HZ * balloon_boot_timeout)
|
|
panic("Initial ballooning failed!\n");
|
|
}
|
|
|
|
schedule_timeout_interruptible(HZ / 10);
|
|
}
|
|
|
|
pr_notice("Initial ballooning down finished.\n");
|
|
|
|
return 0;
|
|
}
|
|
late_initcall_sync(balloon_wait_finish);
|