--- /dev/null
+/*
+ * VMware Balloon driver.
+ *
+ * Copyright (C) 2000-2010, VMware, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Maintained by: Dmitry Torokhov <dtor@vmware.com>
+ */
+
+/*
+ * This is VMware physical memory management driver for Linux. The driver
+ * acts like a "balloon" that can be inflated to reclaim physical pages by
+ * reserving them in the guest and invalidating them in the monitor,
+ * freeing up the underlying machine pages so they can be allocated to
+ * other guests. The balloon can also be deflated to allow the guest to
+ * use more physical memory. Higher level policies can control the sizes
+ * of balloons in VMs in order to manage physical memory resources.
+ */
+
+//#define DEBUG
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/workqueue.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <asm/vmware.h>
+
+MODULE_AUTHOR("VMware, Inc.");
+MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver");
+MODULE_VERSION("1.2.1.0-K");
+MODULE_ALIAS("dmi:*:svnVMware*:*");
+MODULE_ALIAS("vmware_vmmemctl");
+MODULE_LICENSE("GPL");
+
+/*
+ * Various constants controlling rate of inflaint/deflating balloon,
+ * measured in pages.
+ */
+
+/*
+ * Rate of allocating memory when there is no memory pressure
+ * (driver performs non-sleeping allocations).
+ */
+#define VMW_BALLOON_NOSLEEP_ALLOC_MAX 16384U
+
+/*
+ * Rates of memory allocaton when guest experiences memory pressure
+ * (driver performs sleeping allocations).
+ */
+#define VMW_BALLOON_RATE_ALLOC_MIN 512U
+#define VMW_BALLOON_RATE_ALLOC_MAX 2048U
+#define VMW_BALLOON_RATE_ALLOC_INC 16U
+
+/*
+ * Rates for releasing pages while deflating balloon.
+ */
+#define VMW_BALLOON_RATE_FREE_MIN 512U
+#define VMW_BALLOON_RATE_FREE_MAX 16384U
+#define VMW_BALLOON_RATE_FREE_INC 16U
+
+/*
+ * When guest is under memory pressure, use a reduced page allocation
+ * rate for next several cycles.
+ */
+#define VMW_BALLOON_SLOW_CYCLES 4
+
+/*
+ * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't
+ * allow wait (__GFP_WAIT) for NOSLEEP page allocations. Use
+ * __GFP_NOWARN, to suppress page allocation failure warnings.
+ */
+#define VMW_PAGE_ALLOC_NOSLEEP (__GFP_HIGHMEM|__GFP_NOWARN)
+
+/*
+ * Use GFP_HIGHUSER when executing in a separate kernel thread
+ * context and allocation can sleep. This is less stressful to
+ * the guest memory system, since it allows the thread to block
+ * while memory is reclaimed, and won't take pages from emergency
+ * low-memory pools.
+ */
+#define VMW_PAGE_ALLOC_CANSLEEP (GFP_HIGHUSER)
+
+/* Maximum number of page allocations without yielding processor */
+#define VMW_BALLOON_YIELD_THRESHOLD 1024
+
+
+/*
+ * Hypervisor communication port definitions.
+ */
+#define VMW_BALLOON_HV_PORT 0x5670
+#define VMW_BALLOON_HV_MAGIC 0x456c6d6f
+#define VMW_BALLOON_PROTOCOL_VERSION 2
+#define VMW_BALLOON_GUEST_ID 1 /* Linux */
+
+#define VMW_BALLOON_CMD_START 0
+#define VMW_BALLOON_CMD_GET_TARGET 1
+#define VMW_BALLOON_CMD_LOCK 2
+#define VMW_BALLOON_CMD_UNLOCK 3
+#define VMW_BALLOON_CMD_GUEST_ID 4
+
+/* error codes */
+#define VMW_BALLOON_SUCCESS 0
+#define VMW_BALLOON_FAILURE -1
+#define VMW_BALLOON_ERROR_CMD_INVALID 1
+#define VMW_BALLOON_ERROR_PPN_INVALID 2
+#define VMW_BALLOON_ERROR_PPN_LOCKED 3
+#define VMW_BALLOON_ERROR_PPN_UNLOCKED 4
+#define VMW_BALLOON_ERROR_PPN_PINNED 5
+#define VMW_BALLOON_ERROR_PPN_NOTNEEDED 6
+#define VMW_BALLOON_ERROR_RESET 7
+#define VMW_BALLOON_ERROR_BUSY 8
+
+#define VMWARE_BALLOON_CMD(cmd, data, result) \
+({ \
+ unsigned long __stat, __dummy1, __dummy2; \
+ __asm__ __volatile__ ("inl (%%dx)" : \
+ "=a"(__stat), \
+ "=c"(__dummy1), \
+ "=d"(__dummy2), \
+ "=b"(result) : \
+ "0"(VMW_BALLOON_HV_MAGIC), \
+ "1"(VMW_BALLOON_CMD_##cmd), \
+ "2"(VMW_BALLOON_HV_PORT), \
+ "3"(data) : \
+ "memory"); \
+ result &= -1UL; \
+ __stat & -1UL; \
+})
+
+#ifdef CONFIG_DEBUG_FS
+struct vmballoon_stats {
+ unsigned int timer;
+
+ /* allocation statustics */
+ unsigned int alloc;
+ unsigned int alloc_fail;
+ unsigned int sleep_alloc;
+ unsigned int sleep_alloc_fail;
+ unsigned int refused_alloc;
+ unsigned int refused_free;
+ unsigned int free;
+
+ /* monitor operations */
+ unsigned int lock;
+ unsigned int lock_fail;
+ unsigned int unlock;
+ unsigned int unlock_fail;
+ unsigned int target;
+ unsigned int target_fail;
+ unsigned int start;
+ unsigned int start_fail;
+ unsigned int guest_type;
+ unsigned int guest_type_fail;
+};
+
+#define STATS_INC(stat) (stat)++
+#else
+#define STATS_INC(stat)
+#endif
+
+struct vmballoon {
+
+ /* list of reserved physical pages */
+ struct list_head pages;
+
+ /* transient list of non-balloonable pages */
+ struct list_head refused_pages;
+
+ /* balloon size in pages */
+ unsigned int size;
+ unsigned int target;
+
+ /* reset flag */
+ bool reset_required;
+
+ /* adjustment rates (pages per second) */
+ unsigned int rate_alloc;
+ unsigned int rate_free;
+
+ /* slowdown page allocations for next few cycles */
+ unsigned int slow_allocation_cycles;
+
+#ifdef CONFIG_DEBUG_FS
+ /* statistics */
+ struct vmballoon_stats stats;
+
+ /* debugfs file exporting statistics */
+ struct dentry *dbg_entry;
+#endif
+
+ struct sysinfo sysinfo;
+
+ struct delayed_work dwork;
+};
+
+static struct vmballoon balloon;
+static struct workqueue_struct *vmballoon_wq;
+
+/*
+ * Send "start" command to the host, communicating supported version
+ * of the protocol.
+ */
+static bool vmballoon_send_start(struct vmballoon *b)
+{
+ unsigned long status, dummy;
+
+ STATS_INC(b->stats.start);
+
+ status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_PROTOCOL_VERSION, dummy);
+ if (status == VMW_BALLOON_SUCCESS)
+ return true;
+
+ pr_debug("%s - failed, hv returns %ld\n", __func__, status);
+ STATS_INC(b->stats.start_fail);
+ return false;
+}
+
+static bool vmballoon_check_status(struct vmballoon *b, unsigned long status)
+{
+ switch (status) {
+ case VMW_BALLOON_SUCCESS:
+ return true;
+
+ case VMW_BALLOON_ERROR_RESET:
+ b->reset_required = true;
+ /* fall through */
+
+ default:
+ return false;
+ }
+}
+
+/*
+ * Communicate guest type to the host so that it can adjust ballooning
+ * algorithm to the one most appropriate for the guest. This command
+ * is normally issued after sending "start" command and is part of
+ * standard reset sequence.
+ */
+static bool vmballoon_send_guest_id(struct vmballoon *b)
+{
+ unsigned long status, dummy;
+
+ status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy);
+
+ STATS_INC(b->stats.guest_type);
+
+ if (vmballoon_check_status(b, status))
+ return true;
+
+ pr_debug("%s - failed, hv returns %ld\n", __func__, status);
+ STATS_INC(b->stats.guest_type_fail);
+ return false;
+}
+
+/*
+ * Retrieve desired balloon size from the host.
+ */
+static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target)
+{
+ unsigned long status;
+ unsigned long target;
+ unsigned long limit;
+ u32 limit32;
+
+ /*
+ * si_meminfo() is cheap. Moreover, we want to provide dynamic
+ * max balloon size later. So let us call si_meminfo() every
+ * iteration.
+ */
+ si_meminfo(&b->sysinfo);
+ limit = b->sysinfo.totalram;
+
+ /* Ensure limit fits in 32-bits */
+ limit32 = (u32)limit;
+ if (limit != limit32)
+ return false;
+
+ /* update stats */
+ STATS_INC(b->stats.target);
+
+ status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target);
+ if (vmballoon_check_status(b, status)) {
+ *new_target = target;
+ return true;
+ }
+
+ pr_debug("%s - failed, hv returns %ld\n", __func__, status);
+ STATS_INC(b->stats.target_fail);
+ return false;
+}
+
+/*
+ * Notify the host about allocated page so that host can use it without
+ * fear that guest will need it. Host may reject some pages, we need to
+ * check the return value and maybe submit a different page.
+ */
+static bool vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn)
+{
+ unsigned long status, dummy;
+ u32 pfn32;
+
+ pfn32 = (u32)pfn;
+ if (pfn32 != pfn)
+ return false;
+
+ STATS_INC(b->stats.lock);
+
+ status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy);
+ if (vmballoon_check_status(b, status))
+ return true;
+
+ pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
+ STATS_INC(b->stats.lock_fail);
+ return false;
+}
+
+/*
+ * Notify the host that guest intends to release given page back into
+ * the pool of available (to the guest) pages.
+ */
+static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn)
+{
+ unsigned long status, dummy;
+ u32 pfn32;
+
+ pfn32 = (u32)pfn;
+ if (pfn32 != pfn)
+ return false;
+
+ STATS_INC(b->stats.unlock);
+
+ status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy);
+ if (vmballoon_check_status(b, status))
+ return true;
+
+ pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status);
+ STATS_INC(b->stats.unlock_fail);
+ return false;
+}
+
+/*
+ * Quickly release all pages allocated for the balloon. This function is
+ * called when host decides to "reset" balloon for one reason or another.
+ * Unlike normal "deflate" we do not (shall not) notify host of the pages
+ * being released.
+ */
+static void vmballoon_pop(struct vmballoon *b)
+{
+ struct page *page, *next;
+ unsigned int count = 0;
+
+ list_for_each_entry_safe(page, next, &b->pages, lru) {
+ list_del(&page->lru);
+ __free_page(page);
+ STATS_INC(b->stats.free);
+ b->size--;
+
+ if (++count >= b->rate_free) {
+ count = 0;
+ cond_resched();
+ }
+ }
+}
+
+/*
+ * Perform standard reset sequence by popping the balloon (in case it
+ * is not empty) and then restarting protocol. This operation normally
+ * happens when host responds with VMW_BALLOON_ERROR_RESET to a command.
+ */
+static void vmballoon_reset(struct vmballoon *b)
+{
+ /* free all pages, skipping monitor unlock */
+ vmballoon_pop(b);
+
+ if (vmballoon_send_start(b)) {
+ b->reset_required = false;
+ if (!vmballoon_send_guest_id(b))
+ pr_err("failed to send guest ID to the host\n");
+ }
+}
+
+/*
+ * Allocate (or reserve) a page for the balloon and notify the host. If host
+ * refuses the page put it on "refuse" list and allocate another one until host
+ * is satisfied. "Refused" pages are released at the end of inflation cycle
+ * (when we allocate b->rate_alloc pages).
+ */
+static int vmballoon_reserve_page(struct vmballoon *b, bool can_sleep)
+{
+ struct page *page;
+ gfp_t flags;
+ bool locked = false;
+
+ do {
+ if (!can_sleep)
+ STATS_INC(b->stats.alloc);
+ else
+ STATS_INC(b->stats.sleep_alloc);
+
+ flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP;
+ page = alloc_page(flags);
+ if (!page) {
+ if (!can_sleep)
+ STATS_INC(b->stats.alloc_fail);
+ else
+ STATS_INC(b->stats.sleep_alloc_fail);
+ return -ENOMEM;
+ }
+
+ /* inform monitor */
+ locked = vmballoon_send_lock_page(b, page_to_pfn(page));
+ if (!locked) {
+ if (b->reset_required) {
+ __free_page(page);
+ return -EIO;
+ }
+
+ /* place on list of non-balloonable pages, retry allocation */
+ list_add(&page->lru, &b->refused_pages);
+ STATS_INC(b->stats.refused_alloc);
+ }
+ } while (!locked);
+
+ /* track allocated page */
+ list_add(&page->lru, &b->pages);
+
+ /* update balloon size */
+ b->size++;
+
+ return 0;
+}
+
+/*
+ * Release the page allocated for the balloon. Note that we first notify
+ * the host so it can make sure the page will be available for the guest
+ * to use, if needed.
+ */
+static int vmballoon_release_page(struct vmballoon *b, struct page *page)
+{
+ if (!vmballoon_send_unlock_page(b, page_to_pfn(page)))
+ return -EIO;
+
+ list_del(&page->lru);
+
+ /* deallocate page */
+ __free_page(page);
+ STATS_INC(b->stats.free);
+
+ /* update balloon size */
+ b->size--;
+
+ return 0;
+}
+
+/*
+ * Release pages that were allocated while attempting to inflate the
+ * balloon but were refused by the host for one reason or another.
+ */
+static void vmballoon_release_refused_pages(struct vmballoon *b)
+{
+ struct page *page, *next;
+
+ list_for_each_entry_safe(page, next, &b->refused_pages, lru) {
+ list_del(&page->lru);
+ __free_page(page);
+ STATS_INC(b->stats.refused_free);
+ }
+}
+
+/*
+ * Inflate the balloon towards its target size. Note that we try to limit
+ * the rate of allocation to make sure we are not choking the rest of the
+ * system.
+ */
+static void vmballoon_inflate(struct vmballoon *b)
+{
+ unsigned int goal;
+ unsigned int rate;
+ unsigned int i;
+ unsigned int allocations = 0;
+ int error = 0;
+ bool alloc_can_sleep = false;
+
+ pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
+
+ /*
+ * First try NOSLEEP page allocations to inflate balloon.
+ *
+ * If we do not throttle nosleep allocations, we can drain all
+ * free pages in the guest quickly (if the balloon target is high).
+ * As a side-effect, draining free pages helps to inform (force)
+ * the guest to start swapping if balloon target is not met yet,
+ * which is a desired behavior. However, balloon driver can consume
+ * all available CPU cycles if too many pages are allocated in a
+ * second. Therefore, we throttle nosleep allocations even when
+ * the guest is not under memory pressure. OTOH, if we have already
+ * predicted that the guest is under memory pressure, then we
+ * slowdown page allocations considerably.
+ */
+
+ goal = b->target - b->size;
+ /*
+ * Start with no sleep allocation rate which may be higher
+ * than sleeping allocation rate.
+ */
+ rate = b->slow_allocation_cycles ?
+ b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX;
+
+ pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n",
+ __func__, goal, rate, b->rate_alloc);
+
+ for (i = 0; i < goal; i++) {
+
+ error = vmballoon_reserve_page(b, alloc_can_sleep);
+ if (error) {
+ if (error != -ENOMEM) {
+ /*
+ * Not a page allocation failure, stop this
+ * cycle. Maybe we'll get new target from
+ * the host soon.
+ */
+ break;
+ }
+
+ if (alloc_can_sleep) {
+ /*
+ * CANSLEEP page allocation failed, so guest
+ * is under severe memory pressure. Quickly
+ * decrease allocation rate.
+ */
+ b->rate_alloc = max(b->rate_alloc / 2,
+ VMW_BALLOON_RATE_ALLOC_MIN);
+ break;
+ }
+
+ /*
+ * NOSLEEP page allocation failed, so the guest is
+ * under memory pressure. Let us slow down page
+ * allocations for next few cycles so that the guest
+ * gets out of memory pressure. Also, if we already
+ * allocated b->rate_alloc pages, let's pause,
+ * otherwise switch to sleeping allocations.
+ */
+ b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES;
+
+ if (i >= b->rate_alloc)
+ break;
+
+ alloc_can_sleep = true;
+ /* Lower rate for sleeping allocations. */
+ rate = b->rate_alloc;
+ }
+
+ if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) {
+ cond_resched();
+ allocations = 0;
+ }
+
+ if (i >= rate) {
+ /* We allocated enough pages, let's take a break. */
+ break;
+ }
+ }
+
+ /*
+ * We reached our goal without failures so try increasing
+ * allocation rate.
+ */
+ if (error == 0 && i >= b->rate_alloc) {
+ unsigned int mult = i / b->rate_alloc;
+
+ b->rate_alloc =
+ min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC,
+ VMW_BALLOON_RATE_ALLOC_MAX);
+ }
+
+ vmballoon_release_refused_pages(b);
+}
+
+/*
+ * Decrease the size of the balloon allowing guest to use more memory.
+ */
+static void vmballoon_deflate(struct vmballoon *b)
+{
+ struct page *page, *next;
+ unsigned int i = 0;
+ unsigned int goal;
+ int error;
+
+ pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target);
+
+ /* limit deallocation rate */
+ goal = min(b->size - b->target, b->rate_free);
+
+ pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free);
+
+ /* free pages to reach target */
+ list_for_each_entry_safe(page, next, &b->pages, lru) {
+ error = vmballoon_release_page(b, page);
+ if (error) {
+ /* quickly decrease rate in case of error */
+ b->rate_free = max(b->rate_free / 2,
+ VMW_BALLOON_RATE_FREE_MIN);
+ return;
+ }
+
+ if (++i >= goal)
+ break;
+ }
+
+ /* slowly increase rate if there were no errors */
+ b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC,
+ VMW_BALLOON_RATE_FREE_MAX);
+}
+
+/*
+ * Balloon work function: reset protocol, if needed, get the new size and
+ * adjust balloon as needed. Repeat in 1 sec.
+ */
+static void vmballoon_work(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct vmballoon *b = container_of(dwork, struct vmballoon, dwork);
+ unsigned int target;
+
+ STATS_INC(b->stats.timer);
+
+ if (b->reset_required)
+ vmballoon_reset(b);
+
+ if (b->slow_allocation_cycles > 0)
+ b->slow_allocation_cycles--;
+
+ if (vmballoon_send_get_target(b, &target)) {
+ /* update target, adjust size */
+ b->target = target;
+
+ if (b->size < target)
+ vmballoon_inflate(b);
+ else if (b->size > target)
+ vmballoon_deflate(b);
+ }
+
+ queue_delayed_work(vmballoon_wq, dwork, round_jiffies_relative(HZ));
+}
+
+/*
+ * DEBUGFS Interface
+ */
+#ifdef CONFIG_DEBUG_FS
+
+static int vmballoon_debug_show(struct seq_file *f, void *offset)
+{
+ struct vmballoon *b = f->private;
+ struct vmballoon_stats *stats = &b->stats;
+
+ /* format size info */
+ seq_printf(f,
+ "target: %8d pages\n"
+ "current: %8d pages\n",
+ b->target, b->size);
+
+ /* format rate info */
+ seq_printf(f,
+ "rateNoSleepAlloc: %8d pages/sec\n"
+ "rateSleepAlloc: %8d pages/sec\n"
+ "rateFree: %8d pages/sec\n",
+ VMW_BALLOON_NOSLEEP_ALLOC_MAX,
+ b->rate_alloc, b->rate_free);
+
+ seq_printf(f,
+ "\n"
+ "timer: %8u\n"
+ "start: %8u (%4u failed)\n"
+ "guestType: %8u (%4u failed)\n"
+ "lock: %8u (%4u failed)\n"
+ "unlock: %8u (%4u failed)\n"
+ "target: %8u (%4u failed)\n"
+ "primNoSleepAlloc: %8u (%4u failed)\n"
+ "primCanSleepAlloc: %8u (%4u failed)\n"
+ "primFree: %8u\n"
+ "errAlloc: %8u\n"
+ "errFree: %8u\n",
+ stats->timer,
+ stats->start, stats->start_fail,
+ stats->guest_type, stats->guest_type_fail,
+ stats->lock, stats->lock_fail,
+ stats->unlock, stats->unlock_fail,
+ stats->target, stats->target_fail,
+ stats->alloc, stats->alloc_fail,
+ stats->sleep_alloc, stats->sleep_alloc_fail,
+ stats->free,
+ stats->refused_alloc, stats->refused_free);
+
+ return 0;
+}
+
+static int vmballoon_debug_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, vmballoon_debug_show, inode->i_private);
+}
+
+static const struct file_operations vmballoon_debug_fops = {
+ .owner = THIS_MODULE,
+ .open = vmballoon_debug_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int __init vmballoon_debugfs_init(struct vmballoon *b)
+{
+ int error;
+
+ b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b,
+ &vmballoon_debug_fops);
+ if (IS_ERR(b->dbg_entry)) {
+ error = PTR_ERR(b->dbg_entry);
+ pr_err("failed to create debugfs entry, error: %d\n", error);
+ return error;
+ }
+
+ return 0;
+}
+
+static void __exit vmballoon_debugfs_exit(struct vmballoon *b)
+{
+ debugfs_remove(b->dbg_entry);
+}
+
+#else
+
+static inline int vmballoon_debugfs_init(struct vmballoon *b)
+{
+ return 0;
+}
+
+static inline void vmballoon_debugfs_exit(struct vmballoon *b)
+{
+}
+
+#endif /* CONFIG_DEBUG_FS */
+
+static int __init vmballoon_init(void)
+{
+ int error;
+
+ /*
+ * Check if we are running on VMware's hypervisor and bail out
+ * if we are not.
+ */
+ if (!vmware_platform())
+ return -ENODEV;
+
+ vmballoon_wq = create_freezeable_workqueue("vmmemctl");
+ if (!vmballoon_wq) {
+ pr_err("failed to create workqueue\n");
+ return -ENOMEM;
+ }
+
+ INIT_LIST_HEAD(&balloon.pages);
+ INIT_LIST_HEAD(&balloon.refused_pages);
+
+ /* initialize rates */
+ balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX;
+ balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX;
+
+ INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work);
+
+ /*
+ * Start balloon.
+ */
+ if (!vmballoon_send_start(&balloon)) {
+ pr_err("failed to send start command to the host\n");
+ error = -EIO;
+ goto fail;
+ }
+
+ if (!vmballoon_send_guest_id(&balloon)) {
+ pr_err("failed to send guest ID to the host\n");
+ error = -EIO;
+ goto fail;
+ }
+
+ error = vmballoon_debugfs_init(&balloon);
+ if (error)
+ goto fail;
+
+ queue_delayed_work(vmballoon_wq, &balloon.dwork, 0);
+
+ return 0;
+
+fail:
+ destroy_workqueue(vmballoon_wq);
+ return error;
+}
+module_init(vmballoon_init);
+
+static void __exit vmballoon_exit(void)
+{
+ cancel_delayed_work_sync(&balloon.dwork);
+ destroy_workqueue(vmballoon_wq);
+
+ vmballoon_debugfs_exit(&balloon);
+
+ /*
+ * Deallocate all reserved memory, and reset connection with monitor.
+ * Reset connection before deallocating memory to avoid potential for
+ * additional spurious resets from guest touching deallocated pages.
+ */
+ vmballoon_send_start(&balloon);
+ vmballoon_pop(&balloon);
+}
+module_exit(vmballoon_exit);
projects / openwrt / staging / blogic.git / commitdiff