Release 4.11 drivers/virtio/virtio_balloon.c

/*
 * Virtio balloon implementation, inspired by Dor Laor and Marcelo
 * Tosatti's implementations.
 *
 *  Copyright 2008 Rusty Russell IBM Corporation
 *
 *  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; either version 2 of the License, or
 *  (at your option) any 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.  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
 */

#include <linux/virtio.h>
#include <linux/virtio_balloon.h>
#include <linux/swap.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/balloon_compaction.h>
#include <linux/oom.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/magic.h>

/*
 * Balloon device works in 4K page units.  So each page is pointed to by
 * multiple balloon pages.  All memory counters in this driver are in balloon
 * page units.
 */

#define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT)

#define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256

#define OOM_VBALLOON_DEFAULT_PAGES 256

#define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80


static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES;
module_param(oom_pages, int, S_IRUSR | S_IWUSR);
MODULE_PARM_DESC(oom_pages, "pages to free on OOM");

#ifdef CONFIG_BALLOON_COMPACTION

static struct vfsmount *balloon_mnt;
#endif


struct virtio_balloon {
	
struct virtio_device *vdev;
	


struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;

	/* The balloon servicing is delegated to a freezable workqueue. */
	
struct work_struct update_balloon_stats_work;
	
struct work_struct update_balloon_size_work;

	/* Prevent updating balloon when it is being canceled. */
	
spinlock_t stop_update_lock;
	
bool stop_update;

	/* Waiting for host to ack the pages we released. */
	
wait_queue_head_t acked;

	/* Number of balloon pages we've told the Host we're not using. */
	
unsigned int num_pages;
	/*
         * The pages we've told the Host we're not using are enqueued
         * at vb_dev_info->pages list.
         * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE
         * to num_pages above.
         */
	
struct balloon_dev_info vb_dev_info;

	/* Synchronize access/update to this struct virtio_balloon elements */
	
struct mutex balloon_lock;

	/* The array of pfns we tell the Host about. */
	
unsigned int num_pfns;
	
__virtio32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX];

	/* Memory statistics */
	
struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR];

	/* To register callback in oom notifier call chain */
	
struct notifier_block nb;
};


static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID },
	{ 0 },
};



static u32 page_to_balloon_pfn(struct page *page)
{
	unsigned long pfn = page_to_pfn(page);

	BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT);
	/* Convert pfn from Linux page size to balloon page size. */
	return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE;
}

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29
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Michael S. Tsirkin
4
12.12%
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33
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2
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static struct page *balloon_pfn_to_page(u32 pfn)
{
	BUG_ON(pfn % VIRTIO_BALLOON_PAGES_PER_PAGE);
	return pfn_to_page(pfn / VIRTIO_BALLOON_PAGES_PER_PAGE);
}

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24
92.31%
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Hollis Blanchard
2
7.69%
1
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26
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static void balloon_ack(struct virtqueue *vq)
{
	struct virtio_balloon *vb = vq->vdev->priv;

	wake_up(&vb->acked);
}

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Rusty Russell
23
76.67%
1
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Michael S. Tsirkin
7
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30
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static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
{
	struct scatterlist sg;
	unsigned int len;

	sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);

	/* We should always be able to add one buffer to an empty queue. */
	virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
	virtqueue_kick(vq);

	/* When host has read buffer, this completes via balloon_ack */
	wait_event(vb->acked, virtqueue_get_buf(vq, &len));

}

Contributors
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Rusty Russell
70
83.33%
3
60.00%
Michael S. Tsirkin
14
16.67%
2
40.00%
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84
100.00%
5
100.00%



static void set_page_pfns(struct virtio_balloon *vb,
			  __virtio32 pfns[], struct page *page)
{
	unsigned int i;

	/* Set balloon pfns pointing at this page.
         * Note that the first pfn points at start of the page. */
	for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++)
		pfns[i] = cpu_to_virtio32(vb->vdev,
					  page_to_balloon_pfn(page) + i);
}

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57
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static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
{
	struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
	unsigned num_allocated_pages;

	/* We can only do one array worth at a time. */
	num = min(num, ARRAY_SIZE(vb->pfns));

	mutex_lock(&vb->balloon_lock);
	for (vb->num_pfns = 0; vb->num_pfns < num;
	     vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
		struct page *page = balloon_page_enqueue(vb_dev_info);

		if (!page) {
			dev_info_ratelimited(&vb->vdev->dev,
					     "Out of puff! Can't get %u pages\n",
					     VIRTIO_BALLOON_PAGES_PER_PAGE);
			/* Sleep for at least 1/5 of a second before retry. */
			msleep(200);
			break;
		}
		set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
		vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
		if (!virtio_has_feature(vb->vdev,
					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
			adjust_managed_page_count(page, -1);
	}

	num_allocated_pages = vb->num_pfns;
	/* Did we get any? */
	if (vb->num_pfns != 0)
		tell_host(vb, vb->inflate_vq);
	mutex_unlock(&vb->balloon_lock);

	return num_allocated_pages;
}

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Rusty Russell
110
59.14%
1
11.11%
Rafael Aquini
31
16.67%
1
11.11%
Petr Mladek
13
6.99%
1
11.11%
Denis V. Lunev
12
6.45%
1
11.11%
Michael S. Tsirkin
11
5.91%
2
22.22%
Jiang Liu
7
3.76%
1
11.11%
Joe Perches
1
0.54%
1
11.11%
Konstantin Khlebnikov
1
0.54%
1
11.11%
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186
100.00%
9
100.00%



static void release_pages_balloon(struct virtio_balloon *vb)
{
	unsigned int i;
	struct page *page;

	/* Find pfns pointing at start of each page, get pages and free them. */
	for (i = 0; i < vb->num_pfns; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
		page = balloon_pfn_to_page(virtio32_to_cpu(vb->vdev,
							   vb->pfns[i]));
		if (!virtio_has_feature(vb->vdev,
					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
			adjust_managed_page_count(page, 1);
		put_page(page); /* balloon reference */
	}
}

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Rusty Russell
32
38.55%
1
14.29%
Denis V. Lunev
22
26.51%
2
28.57%
Michael S. Tsirkin
18
21.69%
2
28.57%
Jiang Liu
6
7.23%
1
14.29%
Konstantin Khlebnikov
5
6.02%
1
14.29%
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83
100.00%
7
100.00%



static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
{
	unsigned num_freed_pages;
	struct page *page;
	struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;

	/* We can only do one array worth at a time. */
	num = min(num, ARRAY_SIZE(vb->pfns));

	mutex_lock(&vb->balloon_lock);
	/* We can't release more pages than taken */
	num = min(num, (size_t)vb->num_pages);
	for (vb->num_pfns = 0; vb->num_pfns < num;
	     vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
		page = balloon_page_dequeue(vb_dev_info);
		if (!page)
			break;
		set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
		vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
	}

	num_freed_pages = vb->num_pfns;
	/*
         * Note that if
         * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST);
         * is true, we *have* to do it in this order
         */
	if (vb->num_pfns != 0)
		tell_host(vb, vb->deflate_vq);
	release_pages_balloon(vb);
	mutex_unlock(&vb->balloon_lock);
	return num_freed_pages;
}

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Rusty Russell
85
51.20%
1
10.00%
Rafael Aquini
28
16.87%
1
10.00%
Konstantin Neumoin
15
9.04%
1
10.00%
Raushaniya Maksudova
13
7.83%
1
10.00%
Michael S. Tsirkin
10
6.02%
2
20.00%
Luiz Fernando N. Capitulino
8
4.82%
1
10.00%
MinChan Kim
5
3.01%
1
10.00%
Konstantin Khlebnikov
1
0.60%
1
10.00%
Dave Hansen
1
0.60%
1
10.00%
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166
100.00%
10
100.00%



static inline void update_stat(struct virtio_balloon *vb, int idx,
			       u16 tag, u64 val)
{
	BUG_ON(idx >= VIRTIO_BALLOON_S_NR);
	vb->stats[idx].tag = cpu_to_virtio16(vb->vdev, tag);
	vb->stats[idx].val = cpu_to_virtio64(vb->vdev, val);
}

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Adam Litke
50
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Michael S. Tsirkin
14
21.88%
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64
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#define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT)



static unsigned int update_balloon_stats(struct virtio_balloon *vb)
{
	unsigned long events[NR_VM_EVENT_ITEMS];
	struct sysinfo i;
	unsigned int idx = 0;
	long available;

	all_vm_events(events);
	si_meminfo(&i);

	available = si_mem_available();

#ifdef CONFIG_VM_EVENT_COUNTERS
	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
				pages_to_bytes(events[PSWPIN]));
	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT,
				pages_to_bytes(events[PSWPOUT]));
	update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
	update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
#endif
	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE,
				pages_to_bytes(i.freeram));
	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT,
				pages_to_bytes(i.totalram));
	update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL,
				pages_to_bytes(available));

	return idx;
}

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Adam Litke
137
80.12%
1
25.00%
Igor Redko
23
13.45%
1
25.00%
Ladi Prosek
6
3.51%
1
25.00%
Arnd Bergmann
5
2.92%
1
25.00%
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171
100.00%
4
100.00%

/*
 * While most virtqueues communicate guest-initiated requests to the hypervisor,
 * the stats queue operates in reverse.  The driver initializes the virtqueue
 * with a single buffer.  From that point forward, all conversations consist of
 * a hypervisor request (a call to this function) which directs us to refill
 * the virtqueue with a fresh stats buffer.  Since stats collection can sleep,
 * we delegate the job to a freezable workqueue that will do the actual work via
 * stats_handle_request().
 */


static void stats_request(struct virtqueue *vq)
{
	struct virtio_balloon *vb = vq->vdev->priv;

	spin_lock(&vb->stop_update_lock);
	if (!vb->stop_update)
		queue_work(system_freezable_wq, &vb->update_balloon_stats_work);
	spin_unlock(&vb->stop_update_lock);
}

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Adam Litke
27
49.09%
2
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Petr Mladek
22
40.00%
2
40.00%
Michael S. Tsirkin
6
10.91%
1
20.00%
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55
100.00%
5
100.00%



static void stats_handle_request(struct virtio_balloon *vb)
{
	struct virtqueue *vq;
	struct scatterlist sg;
	unsigned int len, num_stats;

	num_stats = update_balloon_stats(vb);

	vq = vb->stats_vq;
	if (!virtqueue_get_buf(vq, &len))
		return;
	sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
	virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
	virtqueue_kick(vq);
}

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Adam Litke
63
68.48%
2
28.57%
Michael S. Tsirkin
17
18.48%
2
28.57%
Ladi Prosek
9
9.78%
1
14.29%
Rusty Russell
3
3.26%
2
28.57%
Total
92
100.00%
7
100.00%



static void virtballoon_changed(struct virtio_device *vdev)
{
	struct virtio_balloon *vb = vdev->priv;
	unsigned long flags;

	spin_lock_irqsave(&vb->stop_update_lock, flags);
	if (!vb->stop_update)
		queue_work(system_freezable_wq, &vb->update_balloon_size_work);
	spin_unlock_irqrestore(&vb->stop_update_lock, flags);
}

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26
42.62%
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61
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3
100.00%



static inline s64 towards_target(struct virtio_balloon *vb)
{
	s64 target;
	u32 num_pages;

	virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages,
		     &num_pages);

	/* Legacy balloon config space is LE, unlike all other devices. */
	if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1))
		num_pages = le32_to_cpu((__force __le32)num_pages);

	target = num_pages;
	return target - vb->num_pages;
}

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Rusty Russell
31
45.59%
3
60.00%
Michael S. Tsirkin
27
39.71%
1
20.00%
David Gibson
10
14.71%
1
20.00%
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68
100.00%
5
100.00%



static void update_balloon_size(struct virtio_balloon *vb)
{
	u32 actual = vb->num_pages;

	/* Legacy balloon config space is LE, unlike all other devices. */
	if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1))
		actual = (__force u32)cpu_to_le32(actual);

	virtio_cwrite(vb->vdev, struct virtio_balloon_config, actual,
		      &actual);
}

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Rusty Russell
31
54.39%
2
50.00%
Michael S. Tsirkin
25
43.86%
1
25.00%
Luiz Fernando N. Capitulino
1
1.75%
1
25.00%
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57
100.00%
4
100.00%

/*
 * virtballoon_oom_notify - release pages when system is under severe
 *                          memory pressure (called from out_of_memory())
 * @self : notifier block struct
 * @dummy: not used
 * @parm : returned - number of freed pages
 *
 * The balancing of memory by use of the virtio balloon should not cause
 * the termination of processes while there are pages in the balloon.
 * If virtio balloon manages to release some memory, it will make the
 * system return and retry the allocation that forced the OOM killer
 * to run.
 */


static int virtballoon_oom_notify(struct notifier_block *self,
				  unsigned long dummy, void *parm)
{
	struct virtio_balloon *vb;
	unsigned long *freed;
	unsigned num_freed_pages;

	vb = container_of(self, struct virtio_balloon, nb);
	if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
		return NOTIFY_OK;

	freed = parm;
	num_freed_pages = leak_balloon(vb, oom_pages);
	update_balloon_size(vb);
	*freed += num_freed_pages;

	return NOTIFY_OK;
}

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85
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1
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85
100.00%
1
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static void update_balloon_stats_func(struct work_struct *work)
{
	struct virtio_balloon *vb;

	vb = container_of(work, struct virtio_balloon,
			  update_balloon_stats_work);
	stats_handle_request(vb);
}

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Petr Mladek
15
45.45%
1
33.33%
Rusty Russell
12
36.36%
1
33.33%
Michael S. Tsirkin
6
18.18%
1
33.33%
Total
33
100.00%
3
100.00%



static void update_balloon_size_func(struct work_struct *work)
{
	struct virtio_balloon *vb;
	s64 diff;

	vb = container_of(work, struct virtio_balloon,
			  update_balloon_size_work);
	diff = towards_target(vb);

	if (diff > 0)
		diff -= fill_balloon(vb, diff);
	else if (diff < 0)
		diff += leak_balloon(vb, -diff);
	update_balloon_size(vb);

	if (diff)
		queue_work(system_freezable_wq, work);
}

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Rusty Russell
48
55.81%
3
42.86%
Petr Mladek
27
31.40%
2
28.57%
Adam Litke
7
8.14%
1
14.29%
Michael S. Tsirkin
4
4.65%
1
14.29%
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86
100.00%
7
100.00%



static int init_vqs(struct virtio_balloon *vb)
{
	struct virtqueue *vqs[3];
	vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request };
	static const char * const names[] = { "inflate", "deflate", "stats" };
	int err, nvqs;

	/*
         * We expect two virtqueues: inflate and deflate, and
         * optionally stat.
         */
	nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2;
	err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names,
			NULL);
	if (err)
		return err;

	vb->inflate_vq = vqs[0];
	vb->deflate_vq = vqs[1];
	if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
		struct scatterlist sg;
		unsigned int num_stats;
		vb->stats_vq = vqs[2];

		/*
                 * Prime this virtqueue with one buffer so the hypervisor can
                 * use it to signal us later (it can't be broken yet!).
                 */
		num_stats = update_balloon_stats(vb);

		sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
		if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL)
		    < 0)
			BUG();
		virtqueue_kick(vb->stats_vq);
	}
	return 0;
}

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Adam Litke
90
42.45%
2
14.29%
Michael S. Tsirkin
47
22.17%
2
14.29%
Rusty Russell
38
17.92%
5
35.71%
Ladi Prosek
18
8.49%
2
14.29%
Amit Shah
15
7.08%
1
7.14%
Christoph Hellwig
2
0.94%
1
7.14%
Stefan Hajnoczi
2
0.94%
1
7.14%
Total
212
100.00%
14
100.00%

#ifdef CONFIG_BALLOON_COMPACTION
/*
 * virtballoon_migratepage - perform the balloon page migration on behalf of
 *                           a compation thread.     (called under page lock)
 * @vb_dev_info: the balloon device
 * @newpage: page that will replace the isolated page after migration finishes.
 * @page   : the isolated (old) page that is about to be migrated to newpage.
 * @mode   : compaction mode -- not used for balloon page migration.
 *
 * After a ballooned page gets isolated by compaction procedures, this is the
 * function that performs the page migration on behalf of a compaction thread
 * The page migration for virtio balloon is done in a simple swap fashion which
 * follows these two macro steps:
 *  1) insert newpage into vb->pages list and update the host about it;
 *  2) update the host about the old page removed from vb->pages list;
 *
 * This function preforms the balloon page migration task.
 * Called through balloon_mapping->a_ops->migratepage
 */


static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
		struct page *newpage, struct page *page, enum migrate_mode mode)
{
	struct virtio_balloon *vb = container_of(vb_dev_info,
			struct virtio_balloon, vb_dev_info);
	unsigned long flags;

	/*
         * In order to avoid lock contention while migrating pages concurrently
         * to leak_balloon() or fill_balloon() we just give up the balloon_lock
         * this turn, as it is easier to retry the page migration later.
         * This also prevents fill_balloon() getting stuck into a mutex
         * recursion in the case it ends up triggering memory compaction
         * while it is attempting to inflate the ballon.
         */
	if (!mutex_trylock(&vb->balloon_lock))
		return -EAGAIN;

	get_page(newpage); /* balloon reference */

	/* balloon's page migration 1st step  -- inflate "newpage" */
	spin_lock_irqsave(&vb_dev_info->pages_lock, flags);
	balloon_page_insert(vb_dev_info, newpage);
	vb_dev_info->isolated_pages--;
	__count_vm_event(BALLOON_MIGRATE);
	spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags);
	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
	set_page_pfns(vb, vb->pfns, newpage);
	tell_host(vb, vb->inflate_vq);

	/* balloon's page migration 2nd step -- deflate "page" */
	balloon_page_delete(page);
	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
	set_page_pfns(vb, vb->pfns, page);
	tell_host(vb, vb->deflate_vq);

	mutex_unlock(&vb->balloon_lock);

	put_page(page); /* balloon reference */

	return MIGRATEPAGE_SUCCESS;
}

Contributors
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Rafael Aquini
142
79.33%
1
14.29%
Konstantin Khlebnikov
31
17.32%
3
42.86%
Michael S. Tsirkin
4
2.23%
1
14.29%
Rashika Kheria
1
0.56%
1
14.29%
MinChan Kim
1
0.56%
1
14.29%
Total
179
100.00%
7
100.00%



static struct dentry *balloon_mount(struct file_system_type *fs_type,
		int flags, const char *dev_name, void *data)
{
	static const struct dentry_operations ops = {
		.d_dname = simple_dname,
        };

	return mount_pseudo(fs_type, "balloon-kvm:", NULL, &ops,
				BALLOON_KVM_MAGIC);
}

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MinChan Kim
53
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1
100.00%
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53
100.00%
1
100.00%


static struct file_system_type balloon_fs = {
	.name           = "balloon-kvm",
	.mount          = balloon_mount,
	.kill_sb        = kill_anon_super,
};

#endif /* CONFIG_BALLOON_COMPACTION */



static int virtballoon_probe(struct virtio_device *vdev)
{
	struct virtio_balloon *vb;
	int err;

	if (!vdev->config->get) {
		dev_err(&vdev->dev, "%s failure: config access disabled\n",
			__func__);
		return -EINVAL;
	}

	vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL);
	if (!vb) {
		err = -ENOMEM;
		goto out;
	}

	INIT_WORK(&vb->update_balloon_stats_work, update_balloon_stats_func);
	INIT_WORK(&vb->update_balloon_size_work, update_balloon_size_func);
	spin_lock_init(&vb->stop_update_lock);
	vb->stop_update = false;
	vb->num_pages = 0;
	mutex_init(&vb->balloon_lock);
	init_waitqueue_head(&vb->acked);
	vb->vdev = vdev;

	balloon_devinfo_init(&vb->vb_dev_info);

	err = init_vqs(vb);
	if (err)
		goto out_free_vb;

	vb->nb.notifier_call = virtballoon_oom_notify;
	vb->nb.priority = VIRTBALLOON_OOM_NOTIFY_PRIORITY;
	err = register_oom_notifier(&vb->nb);
	if (err < 0)
		goto out_del_vqs;

#ifdef CONFIG_BALLOON_COMPACTION
	balloon_mnt = kern_mount(&balloon_fs);
	if (IS_ERR(balloon_mnt)) {
		err = PTR_ERR(balloon_mnt);
		unregister_oom_notifier(&vb->nb);
		goto out_del_vqs;
	}

	vb->vb_dev_info.migratepage = virtballoon_migratepage;
	vb->vb_dev_info.inode = alloc_anon_inode(balloon_mnt->mnt_sb);
	if (IS_ERR(vb->vb_dev_info.inode)) {
		err = PTR_ERR(vb->vb_dev_info.inode);
		kern_unmount(balloon_mnt);
		unregister_oom_notifier(&vb->nb);
		vb->vb_dev_info.inode = NULL;
		goto out_del_vqs;
	}
	vb->vb_dev_info.inode->i_mapping->a_ops = &balloon_aops;
#endif

	virtio_device_ready(vdev);

	if (towards_target(vb))
		virtballoon_changed(vdev);
	return 0;

out_del_vqs:
	vdev->config->del_vqs(vdev);
out_free_vb:
	kfree(vb);
out:
	return err;
}

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CommitProp
MinChan Kim
124
34.25%
1
7.69%
Amit Shah
82
22.65%
1
7.69%
Michael S. Tsirkin
41
11.33%
4
30.77%
Raushaniya Maksudova
33
9.12%
1
7.69%
Petr Mladek
27
7.46%
2
15.38%
Rusty Russell
26
7.18%
1
7.69%
Rafael Aquini
12
3.31%
1
7.69%
Konstantin Neumoin
12
3.31%
1
7.69%
Konstantin Khlebnikov
5
1.38%
1
7.69%
Total
362
100.00%
13
100.00%



static void remove_common(struct virtio_balloon *vb)
{
	/* There might be pages left in the balloon: free them. */
	while (vb->num_pages)
		leak_balloon(vb, vb->num_pages);
	update_balloon_size(vb);

	/* Now we reset the device so we can clean up the queues. */
	vb->vdev->config->reset(vb->vdev);

	vb->vdev->config->del_vqs(vb->vdev);
}

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Rusty Russell
38
64.41%
1
25.00%
Amit Shah
20
33.90%
2
50.00%
Michael S. Tsirkin
1
1.69%
1
25.00%
Total
59
100.00%
4
100.00%



static void virtballoon_remove(struct virtio_device *vdev)
{
	struct virtio_balloon *vb = vdev->priv;

	unregister_oom_notifier(&vb->nb);

	spin_lock_irq(&vb->stop_update_lock);
	vb->stop_update = true;
	spin_unlock_irq(&vb->stop_update_lock);
	cancel_work_sync(&vb->update_balloon_size_work);
	cancel_work_sync(&vb->update_balloon_stats_work);

	remove_common(vb);
#ifdef CONFIG_BALLOON_COMPACTION
	if (vb->vb_dev_info.inode)
		iput(vb->vb_dev_info.inode);

	kern_unmount(balloon_mnt);
#endif
	kfree(vb);
}

Contributors
Person
Tokens
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Commits
CommitProp
Petr Mladek
30
29.13%
2
28.57%
Amit Shah
29
28.16%
1
14.29%
MinChan Kim
17
16.50%
1
14.29%
Yisheng Xie
10
9.71%
1
14.29%
Rusty Russell
9
8.74%
1
14.29%
Raushaniya Maksudova
8
7.77%
1
14.29%
Total
103
100.00%
7
100.00%

#ifdef CONFIG_PM_SLEEP


static int virtballoon_freeze(struct virtio_device *vdev)
{
	struct virtio_balloon *vb = vdev->priv;

	/*
         * The workqueue is already frozen by the PM core before this
         * function is called.
         */
	remove_common(vb);
	return 0;
}

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Amit Shah
28
96.55%
3
75.00%
Petr Mladek
1
3.45%
1
25.00%
Total
29
100.00%
4
100.00%



static int virtballoon_restore(struct virtio_device *vdev)
{
	struct virtio_balloon *vb = vdev->priv;
	int ret;

	ret = init_vqs(vdev->priv);
	if (ret)
		return ret;

	virtio_device_ready(vdev);

	if (towards_target(vb))
		virtballoon_changed(vdev);
	update_balloon_size(vb);
	return 0;
}
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CommitProp
Amit Shah
53
82.81%
3
60.00%
Petr Mladek
6
9.38%
1
20.00%
Michael S. Tsirkin
5
7.81%
1
20.00%
Total
64
100.00%
5
100.00%

#endif


static unsigned int features[] = {
	VIRTIO_BALLOON_F_MUST_TELL_HOST,
	VIRTIO_BALLOON_F_STATS_VQ,
	VIRTIO_BALLOON_F_DEFLATE_ON_OOM,
};


static struct virtio_driver virtio_balloon_driver = {
	.feature_table = features,
	.feature_table_size = ARRAY_SIZE(features),
	.driver.name =	KBUILD_MODNAME,
	.driver.owner =	THIS_MODULE,
	.id_table =	id_table,
	.probe =	virtballoon_probe,
	.remove =	virtballoon_remove,
	.config_changed = virtballoon_changed,
#ifdef CONFIG_PM_SLEEP
	.freeze	=	virtballoon_freeze,
	.restore =	virtballoon_restore,
#endif
};


module_virtio_driver(virtio_balloon_driver);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio balloon driver");
MODULE_LICENSE("GPL");
Overall Contributors
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Rusty Russell
734
25.87%
10
15.38%
Adam Litke
395
13.92%
2
3.08%
Michael S. Tsirkin
352
12.41%
10
15.38%
Amit Shah
247
8.71%
6
9.23%
MinChan Kim
236
8.32%
3
4.62%
Rafael Aquini
236
8.32%
1
1.54%
Petr Mladek
190
6.70%
2
3.08%
Raushaniya Maksudova
182
6.42%
2
3.08%
Konstantin Khlebnikov
44
1.55%
3
4.62%
Denis V. Lunev
34
1.20%
2
3.08%
Ladi Prosek
33
1.16%
2
3.08%
Hollis Blanchard
31
1.09%
1
1.54%
Konstantin Neumoin
27
0.95%
2
3.08%
Igor Redko
26
0.92%
1
1.54%
Jiang Liu
13
0.46%
1
1.54%
Yisheng Xie
10
0.35%
1
1.54%
David Gibson
10
0.35%
1
1.54%
Luiz Fernando N. Capitulino
9
0.32%
2
3.08%
Arnd Bergmann
5
0.18%
1
1.54%
Paul Gortmaker
3
0.11%
1
1.54%
Ingo Molnar
3
0.11%
1
1.54%
Johann Felix Soden
3
0.11%
1
1.54%
Tejun Heo
3
0.11%
1
1.54%
Christoph Hellwig
2
0.07%
1
1.54%
Aaron Lu
2
0.07%
1
1.54%
Stefan Hajnoczi
2
0.07%
1
1.54%
Sasha Levin
1
0.04%
1
1.54%
Rashika Kheria
1
0.04%
1
1.54%
Joe Perches
1
0.04%
1
1.54%
Jeff Mahoney
1
0.04%
1
1.54%
Dave Hansen
1
0.04%
1
1.54%
Total
2837
100.00%
65
100.00%
Directory: drivers/virtio

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