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503b158fc3
We currently initialize the memmap such that PG_reserved is set and the refcount of the page is 1. In virtio-mem code, we have to manually clear that PG_reserved flag to make memory offlining with partially hotplugged memory blocks possible: has_unmovable_pages() would otherwise bail out on such pages. We want to avoid PG_reserved where possible and move to typed pages instead. Further, we want to further enlighten memory offlining code about PG_offline: offline pages in an online memory section. One example is handling managed page count adjustments in a cleaner way during memory offlining. So let's initialize the pages with PG_offline instead of PG_reserved. generic_online_page()->__free_pages_core() will now clear that flag before handing that memory to the buddy. Note that the page refcount is still 1 and would forbid offlining of such memory except when special care is take during GOING_OFFLINE as currently only implemented by virtio-mem. With this change, we can now get non-PageReserved() pages in the XEN balloon list. From what I can tell, that can already happen via decrease_reservation(), so that should be fine. HV-balloon should not really observe a change: partial online memory blocks still cannot get surprise-offlined, because the refcount of these PageOffline() pages is 1. Update virtio-mem, HV-balloon and XEN-balloon code to be aware that hotplugged pages are now PageOffline() instead of PageReserved() before they are handed over to the buddy. We'll leave the ZONE_DEVICE case alone for now. Note that self-hosted vmemmap pages will no longer be marked as reserved. This matches ordinary vmemmap pages allocated from the buddy during memory hotplug. Now, really only vmemmap pages allocated from memblock during early boot will be marked reserved. Existing PageReserved() checks seem to be handling all relevant cases correctly even after this change. Link: https://lkml.kernel.org/r/20240607090939.89524-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Oscar Salvador <osalvador@suse.de> [generic memory-hotplug bits] Cc: Alexander Potapenko <glider@google.com> Cc: Dexuan Cui <decui@microsoft.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eugenio Pérez <eperezma@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Marco Elver <elver@google.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
786 lines
19 KiB
C
786 lines
19 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 <linux/jiffies.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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#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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if (!PageOffline(page))
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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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/*
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* Relinquish the page back to the allocator. Note that
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* some pages, including ones added via xen_online_page(), might
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* not be marked reserved; free_reserved_page() will handle that.
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*/
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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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|
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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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|
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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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|
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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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/*
|
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* Ensure that ballooned highmem pages don't have kmaps.
|
|
*
|
|
* Do this before changing the p2m as kmap_flush_unused()
|
|
* reads PTEs to obtain pages (and hence needs the original
|
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* p2m entry).
|
|
*/
|
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kmap_flush_unused();
|
|
|
|
/*
|
|
* Setup the frame, update direct mapping, invalidate P2M,
|
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* and add to balloon.
|
|
*/
|
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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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|
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xenmem_reservation_va_mapping_reset(1, &page);
|
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|
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list_del(&page->lru);
|
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|
|
balloon_append(page);
|
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}
|
|
|
|
flush_tlb_all();
|
|
|
|
ret = xenmem_reservation_decrease(nr_pages, frame_list);
|
|
BUG_ON(ret != nr_pages);
|
|
|
|
balloon_stats.current_pages -= nr_pages;
|
|
|
|
return state;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
|
|
static void __init balloon_add_regions(void)
|
|
{
|
|
unsigned long start_pfn, pages;
|
|
unsigned long pfn, extra_pfn_end;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
|
|
pages = xen_extra_mem[i].n_pfns;
|
|
if (!pages)
|
|
continue;
|
|
|
|
start_pfn = xen_extra_mem[i].start_pfn;
|
|
|
|
/*
|
|
* 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++)
|
|
balloon_append(pfn_to_page(pfn));
|
|
|
|
balloon_stats.total_pages += extra_pfn_end - start_pfn;
|
|
}
|
|
}
|
|
|
|
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_init("xen/balloon", balloon_table);
|
|
#endif
|
|
|
|
balloon_add_regions();
|
|
|
|
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 (time_is_before_eq_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);
|