From 95099d4622f8cb224d94e314c7a8e0df60b13f87 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 08:38:01 +0000
Subject: [PATCH] enable docker ppp
---
kernel/drivers/virtio/virtio_balloon.c | 588 ++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 501 insertions(+), 87 deletions(-)
diff --git a/kernel/drivers/virtio/virtio_balloon.c b/kernel/drivers/virtio/virtio_balloon.c
index 1afcbef..8985fc2 100644
--- a/kernel/drivers/virtio/virtio_balloon.c
+++ b/kernel/drivers/virtio/virtio_balloon.c
@@ -1,22 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
@@ -27,10 +14,13 @@
#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>
+#include <linux/pseudo_fs.h>
+#include <linux/page_reporting.h>
/*
* Balloon device works in 4K page units. So each page is pointed to by
@@ -39,15 +29,44 @@
*/
#define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT)
#define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256
-#define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80
+/* Maximum number of (4k) pages to deflate on OOM notifications. */
+#define VIRTIO_BALLOON_OOM_NR_PAGES 256
+#define VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY 80
+
+#define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN | \
+ __GFP_NOMEMALLOC)
+/* The order of free page blocks to report to host */
+#define VIRTIO_BALLOON_HINT_BLOCK_ORDER (MAX_ORDER - 1)
+/* The size of a free page block in bytes */
+#define VIRTIO_BALLOON_HINT_BLOCK_BYTES \
+ (1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT))
+#define VIRTIO_BALLOON_HINT_BLOCK_PAGES (1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER)
#ifdef CONFIG_BALLOON_COMPACTION
static struct vfsmount *balloon_mnt;
#endif
+enum virtio_balloon_vq {
+ VIRTIO_BALLOON_VQ_INFLATE,
+ VIRTIO_BALLOON_VQ_DEFLATE,
+ VIRTIO_BALLOON_VQ_STATS,
+ VIRTIO_BALLOON_VQ_FREE_PAGE,
+ VIRTIO_BALLOON_VQ_REPORTING,
+ VIRTIO_BALLOON_VQ_MAX
+};
+
+enum virtio_balloon_config_read {
+ VIRTIO_BALLOON_CONFIG_READ_CMD_ID = 0,
+};
+
struct virtio_balloon {
struct virtio_device *vdev;
- struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
+ struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq;
+
+ /* Balloon's own wq for cpu-intensive work items */
+ struct workqueue_struct *balloon_wq;
+ /* The free page reporting work item submitted to the balloon wq */
+ struct work_struct report_free_page_work;
/* The balloon servicing is delegated to a freezable workqueue. */
struct work_struct update_balloon_stats_work;
@@ -56,6 +75,24 @@
/* Prevent updating balloon when it is being canceled. */
spinlock_t stop_update_lock;
bool stop_update;
+ /* Bitmap to indicate if reading the related config fields are needed */
+ unsigned long config_read_bitmap;
+
+ /* The list of allocated free pages, waiting to be given back to mm */
+ struct list_head free_page_list;
+ spinlock_t free_page_list_lock;
+ /* The number of free page blocks on the above list */
+ unsigned long num_free_page_blocks;
+ /*
+ * The cmd id received from host.
+ * Read it via virtio_balloon_cmd_id_received to get the latest value
+ * sent from host.
+ */
+ u32 cmd_id_received_cache;
+ /* The cmd id that is actively in use */
+ __virtio32 cmd_id_active;
+ /* Buffer to store the stop sign */
+ __virtio32 cmd_id_stop;
/* Waiting for host to ack the pages we released. */
wait_queue_head_t acked;
@@ -80,11 +117,18 @@
/* Memory statistics */
struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR];
- /* To register a shrinker to shrink memory upon memory pressure */
+ /* Shrinker to return free pages - VIRTIO_BALLOON_F_FREE_PAGE_HINT */
struct shrinker shrinker;
+
+ /* OOM notifier to deflate on OOM - VIRTIO_BALLOON_F_DEFLATE_ON_OOM */
+ struct notifier_block oom_nb;
+
+ /* Free page reporting device */
+ struct virtqueue *reporting_vq;
+ struct page_reporting_dev_info pr_dev_info;
};
-static struct virtio_device_id id_table[] = {
+static const struct virtio_device_id id_table[] = {
{ VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID },
{ 0 },
};
@@ -119,6 +163,33 @@
/* When host has read buffer, this completes via balloon_ack */
wait_event(vb->acked, virtqueue_get_buf(vq, &len));
+}
+
+static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_info,
+ struct scatterlist *sg, unsigned int nents)
+{
+ struct virtio_balloon *vb =
+ container_of(pr_dev_info, struct virtio_balloon, pr_dev_info);
+ struct virtqueue *vq = vb->reporting_vq;
+ unsigned int unused, err;
+
+ /* We should always be able to add these buffers to an empty queue. */
+ err = virtqueue_add_inbuf(vq, sg, nents, vb, GFP_NOWAIT | __GFP_NOWARN);
+
+ /*
+ * In the extremely unlikely case that something has occurred and we
+ * are able to trigger an error we will simply display a warning
+ * and exit without actually processing the pages.
+ */
+ if (WARN_ON_ONCE(err))
+ return err;
+
+ virtqueue_kick(vq);
+
+ /* When host has read buffer, this completes via balloon_ack */
+ wait_event(vb->acked, virtqueue_get_buf(vq, &unused));
+
+ return 0;
}
static void set_page_pfns(struct virtio_balloon *vb,
@@ -322,31 +393,65 @@
virtqueue_kick(vq);
}
+static inline s64 towards_target(struct virtio_balloon *vb)
+{
+ s64 target;
+ u32 num_pages;
+
+ /* Legacy balloon config space is LE, unlike all other devices. */
+ virtio_cread_le(vb->vdev, struct virtio_balloon_config, num_pages,
+ &num_pages);
+
+ target = num_pages;
+ return target - vb->num_pages;
+}
+
+/* Gives back @num_to_return blocks of free pages to mm. */
+static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb,
+ unsigned long num_to_return)
+{
+ struct page *page;
+ unsigned long num_returned;
+
+ spin_lock_irq(&vb->free_page_list_lock);
+ for (num_returned = 0; num_returned < num_to_return; num_returned++) {
+ page = balloon_page_pop(&vb->free_page_list);
+ if (!page)
+ break;
+ free_pages((unsigned long)page_address(page),
+ VIRTIO_BALLOON_HINT_BLOCK_ORDER);
+ }
+ vb->num_free_page_blocks -= num_returned;
+ spin_unlock_irq(&vb->free_page_list_lock);
+
+ return num_returned;
+}
+
+static void virtio_balloon_queue_free_page_work(struct virtio_balloon *vb)
+{
+ if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
+ return;
+
+ /* No need to queue the work if the bit was already set. */
+ if (test_and_set_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID,
+ &vb->config_read_bitmap))
+ return;
+
+ queue_work(vb->balloon_wq, &vb->report_free_page_work);
+}
+
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);
+ if (!vb->stop_update) {
+ queue_work(system_freezable_wq,
+ &vb->update_balloon_size_work);
+ virtio_balloon_queue_free_page_work(vb);
+ }
spin_unlock_irqrestore(&vb->stop_update_lock, flags);
-}
-
-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;
}
static void update_balloon_size(struct virtio_balloon *vb)
@@ -354,11 +459,8 @@
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);
+ virtio_cwrite_le(vb->vdev, struct virtio_balloon_config, actual,
+ &actual);
}
static void update_balloon_stats_func(struct work_struct *work)
@@ -379,9 +481,12 @@
update_balloon_size_work);
diff = towards_target(vb);
+ if (!diff)
+ return;
+
if (diff > 0)
diff -= fill_balloon(vb, diff);
- else if (diff < 0)
+ else
diff += leak_balloon(vb, -diff);
update_balloon_size(vb);
@@ -391,26 +496,52 @@
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;
+ struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX];
+ vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX];
+ const char *names[VIRTIO_BALLOON_VQ_MAX];
+ int err;
/*
- * We expect two virtqueues: inflate and deflate, and
- * optionally stat.
+ * Inflateq and deflateq are used unconditionally. The names[]
+ * will be NULL if the related feature is not enabled, which will
+ * cause no allocation for the corresponding virtqueue in find_vqs.
*/
- nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2;
- err = virtio_find_vqs(vb->vdev, nvqs, vqs, callbacks, names, NULL);
+ callbacks[VIRTIO_BALLOON_VQ_INFLATE] = balloon_ack;
+ names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate";
+ callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack;
+ names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate";
+ callbacks[VIRTIO_BALLOON_VQ_STATS] = NULL;
+ names[VIRTIO_BALLOON_VQ_STATS] = NULL;
+ callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
+ names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
+ names[VIRTIO_BALLOON_VQ_REPORTING] = NULL;
+
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
+ names[VIRTIO_BALLOON_VQ_STATS] = "stats";
+ callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request;
+ }
+
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
+ names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq";
+ callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
+ }
+
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) {
+ names[VIRTIO_BALLOON_VQ_REPORTING] = "reporting_vq";
+ callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack;
+ }
+
+ err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX,
+ vqs, callbacks, names, NULL, NULL);
if (err)
return err;
- vb->inflate_vq = vqs[0];
- vb->deflate_vq = vqs[1];
+ vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE];
+ vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE];
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
struct scatterlist sg;
unsigned int num_stats;
- vb->stats_vq = vqs[2];
+ vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS];
/*
* Prime this virtqueue with one buffer so the hypervisor can
@@ -428,7 +559,176 @@
}
virtqueue_kick(vb->stats_vq);
}
+
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
+ vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE];
+
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING))
+ vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING];
+
return 0;
+}
+
+static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb)
+{
+ if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID,
+ &vb->config_read_bitmap)) {
+ /* Legacy balloon config space is LE, unlike all other devices. */
+ virtio_cread_le(vb->vdev, struct virtio_balloon_config,
+ free_page_hint_cmd_id,
+ &vb->cmd_id_received_cache);
+ }
+
+ return vb->cmd_id_received_cache;
+}
+
+static int send_cmd_id_start(struct virtio_balloon *vb)
+{
+ struct scatterlist sg;
+ struct virtqueue *vq = vb->free_page_vq;
+ int err, unused;
+
+ /* Detach all the used buffers from the vq */
+ while (virtqueue_get_buf(vq, &unused))
+ ;
+
+ vb->cmd_id_active = cpu_to_virtio32(vb->vdev,
+ virtio_balloon_cmd_id_received(vb));
+ sg_init_one(&sg, &vb->cmd_id_active, sizeof(vb->cmd_id_active));
+ err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_active, GFP_KERNEL);
+ if (!err)
+ virtqueue_kick(vq);
+ return err;
+}
+
+static int send_cmd_id_stop(struct virtio_balloon *vb)
+{
+ struct scatterlist sg;
+ struct virtqueue *vq = vb->free_page_vq;
+ int err, unused;
+
+ /* Detach all the used buffers from the vq */
+ while (virtqueue_get_buf(vq, &unused))
+ ;
+
+ sg_init_one(&sg, &vb->cmd_id_stop, sizeof(vb->cmd_id_stop));
+ err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_stop, GFP_KERNEL);
+ if (!err)
+ virtqueue_kick(vq);
+ return err;
+}
+
+static int get_free_page_and_send(struct virtio_balloon *vb)
+{
+ struct virtqueue *vq = vb->free_page_vq;
+ struct page *page;
+ struct scatterlist sg;
+ int err, unused;
+ void *p;
+
+ /* Detach all the used buffers from the vq */
+ while (virtqueue_get_buf(vq, &unused))
+ ;
+
+ page = alloc_pages(VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG,
+ VIRTIO_BALLOON_HINT_BLOCK_ORDER);
+ /*
+ * When the allocation returns NULL, it indicates that we have got all
+ * the possible free pages, so return -EINTR to stop.
+ */
+ if (!page)
+ return -EINTR;
+
+ p = page_address(page);
+ sg_init_one(&sg, p, VIRTIO_BALLOON_HINT_BLOCK_BYTES);
+ /* There is always 1 entry reserved for the cmd id to use. */
+ if (vq->num_free > 1) {
+ err = virtqueue_add_inbuf(vq, &sg, 1, p, GFP_KERNEL);
+ if (unlikely(err)) {
+ free_pages((unsigned long)p,
+ VIRTIO_BALLOON_HINT_BLOCK_ORDER);
+ return err;
+ }
+ virtqueue_kick(vq);
+ spin_lock_irq(&vb->free_page_list_lock);
+ balloon_page_push(&vb->free_page_list, page);
+ vb->num_free_page_blocks++;
+ spin_unlock_irq(&vb->free_page_list_lock);
+ } else {
+ /*
+ * The vq has no available entry to add this page block, so
+ * just free it.
+ */
+ free_pages((unsigned long)p, VIRTIO_BALLOON_HINT_BLOCK_ORDER);
+ }
+
+ return 0;
+}
+
+static int send_free_pages(struct virtio_balloon *vb)
+{
+ int err;
+ u32 cmd_id_active;
+
+ while (1) {
+ /*
+ * If a stop id or a new cmd id was just received from host,
+ * stop the reporting.
+ */
+ cmd_id_active = virtio32_to_cpu(vb->vdev, vb->cmd_id_active);
+ if (unlikely(cmd_id_active !=
+ virtio_balloon_cmd_id_received(vb)))
+ break;
+
+ /*
+ * The free page blocks are allocated and sent to host one by
+ * one.
+ */
+ err = get_free_page_and_send(vb);
+ if (err == -EINTR)
+ break;
+ else if (unlikely(err))
+ return err;
+ }
+
+ return 0;
+}
+
+static void virtio_balloon_report_free_page(struct virtio_balloon *vb)
+{
+ int err;
+ struct device *dev = &vb->vdev->dev;
+
+ /* Start by sending the received cmd id to host with an outbuf. */
+ err = send_cmd_id_start(vb);
+ if (unlikely(err))
+ dev_err(dev, "Failed to send a start id, err = %d\n", err);
+
+ err = send_free_pages(vb);
+ if (unlikely(err))
+ dev_err(dev, "Failed to send a free page, err = %d\n", err);
+
+ /* End by sending a stop id to host with an outbuf. */
+ err = send_cmd_id_stop(vb);
+ if (unlikely(err))
+ dev_err(dev, "Failed to send a stop id, err = %d\n", err);
+}
+
+static void report_free_page_func(struct work_struct *work)
+{
+ struct virtio_balloon *vb = container_of(work, struct virtio_balloon,
+ report_free_page_work);
+ u32 cmd_id_received;
+
+ cmd_id_received = virtio_balloon_cmd_id_received(vb);
+ if (cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) {
+ /* Pass ULONG_MAX to give back all the free pages */
+ return_free_pages_to_mm(vb, ULONG_MAX);
+ } else if (cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP &&
+ cmd_id_received !=
+ virtio32_to_cpu(vb->vdev, vb->cmd_id_active)) {
+ virtio_balloon_report_free_page(vb);
+ }
}
#ifdef CONFIG_BALLOON_COMPACTION
@@ -506,46 +806,39 @@
return MIGRATEPAGE_SUCCESS;
}
-static struct dentry *balloon_mount(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
+static int balloon_init_fs_context(struct fs_context *fc)
{
- static const struct dentry_operations ops = {
- .d_dname = simple_dname,
- };
-
- return mount_pseudo(fs_type, "balloon-kvm:", NULL, &ops,
- BALLOON_KVM_MAGIC);
+ return init_pseudo(fc, BALLOON_KVM_MAGIC) ? 0 : -ENOMEM;
}
static struct file_system_type balloon_fs = {
.name = "balloon-kvm",
- .mount = balloon_mount,
+ .init_fs_context = balloon_init_fs_context,
.kill_sb = kill_anon_super,
};
#endif /* CONFIG_BALLOON_COMPACTION */
+static unsigned long shrink_free_pages(struct virtio_balloon *vb,
+ unsigned long pages_to_free)
+{
+ unsigned long blocks_to_free, blocks_freed;
+
+ pages_to_free = round_up(pages_to_free,
+ VIRTIO_BALLOON_HINT_BLOCK_PAGES);
+ blocks_to_free = pages_to_free / VIRTIO_BALLOON_HINT_BLOCK_PAGES;
+ blocks_freed = return_free_pages_to_mm(vb, blocks_to_free);
+
+ return blocks_freed * VIRTIO_BALLOON_HINT_BLOCK_PAGES;
+}
+
static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker,
struct shrink_control *sc)
{
- unsigned long pages_to_free, pages_freed = 0;
struct virtio_balloon *vb = container_of(shrinker,
struct virtio_balloon, shrinker);
- pages_to_free = sc->nr_to_scan * VIRTIO_BALLOON_PAGES_PER_PAGE;
-
- /*
- * One invocation of leak_balloon can deflate at most
- * VIRTIO_BALLOON_ARRAY_PFNS_MAX balloon pages, so we call it
- * multiple times to deflate pages till reaching pages_to_free.
- */
- while (vb->num_pages && pages_to_free) {
- pages_to_free -= pages_freed;
- pages_freed += leak_balloon(vb, pages_to_free);
- }
- update_balloon_size(vb);
-
- return pages_freed / VIRTIO_BALLOON_PAGES_PER_PAGE;
+ return shrink_free_pages(vb, sc->nr_to_scan);
}
static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker,
@@ -554,7 +847,21 @@
struct virtio_balloon *vb = container_of(shrinker,
struct virtio_balloon, shrinker);
- return vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE;
+ return vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES;
+}
+
+static int virtio_balloon_oom_notify(struct notifier_block *nb,
+ unsigned long dummy, void *parm)
+{
+ struct virtio_balloon *vb = container_of(nb,
+ struct virtio_balloon, oom_nb);
+ unsigned long *freed = parm;
+
+ *freed += leak_balloon(vb, VIRTIO_BALLOON_OOM_NR_PAGES) /
+ VIRTIO_BALLOON_PAGES_PER_PAGE;
+ update_balloon_size(vb);
+
+ return NOTIFY_OK;
}
static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb)
@@ -612,27 +919,107 @@
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);
- goto out_del_vqs;
+ goto out_kern_unmount;
}
vb->vb_dev_info.inode->i_mapping->a_ops = &balloon_aops;
#endif
- /*
- * We continue to use VIRTIO_BALLOON_F_DEFLATE_ON_OOM to decide if a
- * shrinker needs to be registered to relieve memory pressure.
- */
- if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) {
+ if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
+ /*
+ * There is always one entry reserved for cmd id, so the ring
+ * size needs to be at least two to report free page hints.
+ */
+ if (virtqueue_get_vring_size(vb->free_page_vq) < 2) {
+ err = -ENOSPC;
+ goto out_iput;
+ }
+ vb->balloon_wq = alloc_workqueue("balloon-wq",
+ WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0);
+ if (!vb->balloon_wq) {
+ err = -ENOMEM;
+ goto out_iput;
+ }
+ INIT_WORK(&vb->report_free_page_work, report_free_page_func);
+ vb->cmd_id_received_cache = VIRTIO_BALLOON_CMD_ID_STOP;
+ vb->cmd_id_active = cpu_to_virtio32(vb->vdev,
+ VIRTIO_BALLOON_CMD_ID_STOP);
+ vb->cmd_id_stop = cpu_to_virtio32(vb->vdev,
+ VIRTIO_BALLOON_CMD_ID_STOP);
+ spin_lock_init(&vb->free_page_list_lock);
+ INIT_LIST_HEAD(&vb->free_page_list);
+ /*
+ * We're allowed to reuse any free pages, even if they are
+ * still to be processed by the host.
+ */
err = virtio_balloon_register_shrinker(vb);
if (err)
- goto out_del_vqs;
+ goto out_del_balloon_wq;
}
+
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) {
+ vb->oom_nb.notifier_call = virtio_balloon_oom_notify;
+ vb->oom_nb.priority = VIRTIO_BALLOON_OOM_NOTIFY_PRIORITY;
+ err = register_oom_notifier(&vb->oom_nb);
+ if (err < 0)
+ goto out_unregister_shrinker;
+ }
+
+ if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) {
+ /* Start with poison val of 0 representing general init */
+ __u32 poison_val = 0;
+
+ /*
+ * Let the hypervisor know that we are expecting a
+ * specific value to be written back in balloon pages.
+ *
+ * If the PAGE_POISON value was larger than a byte we would
+ * need to byte swap poison_val here to guarantee it is
+ * little-endian. However for now it is a single byte so we
+ * can pass it as-is.
+ */
+ if (!want_init_on_free())
+ memset(&poison_val, PAGE_POISON, sizeof(poison_val));
+
+ virtio_cwrite_le(vb->vdev, struct virtio_balloon_config,
+ poison_val, &poison_val);
+ }
+
+ vb->pr_dev_info.report = virtballoon_free_page_report;
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) {
+ unsigned int capacity;
+
+ capacity = virtqueue_get_vring_size(vb->reporting_vq);
+ if (capacity < PAGE_REPORTING_CAPACITY) {
+ err = -ENOSPC;
+ goto out_unregister_oom;
+ }
+
+ err = page_reporting_register(&vb->pr_dev_info);
+ if (err)
+ goto out_unregister_oom;
+ }
+
virtio_device_ready(vdev);
if (towards_target(vb))
virtballoon_changed(vdev);
return 0;
+out_unregister_oom:
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
+ unregister_oom_notifier(&vb->oom_nb);
+out_unregister_shrinker:
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
+ virtio_balloon_unregister_shrinker(vb);
+out_del_balloon_wq:
+ if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
+ destroy_workqueue(vb->balloon_wq);
+out_iput:
+#ifdef CONFIG_BALLOON_COMPACTION
+ iput(vb->vb_dev_info.inode);
+out_kern_unmount:
+ kern_unmount(balloon_mnt);
out_del_vqs:
+#endif
vdev->config->del_vqs(vdev);
out_free_vb:
kfree(vb);
@@ -647,6 +1034,10 @@
leak_balloon(vb, vb->num_pages);
update_balloon_size(vb);
+ /* There might be free pages that are being reported: release them. */
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
+ return_free_pages_to_mm(vb, ULONG_MAX);
+
/* Now we reset the device so we can clean up the queues. */
vb->vdev->config->reset(vb->vdev);
@@ -657,13 +1048,22 @@
{
struct virtio_balloon *vb = vdev->priv;
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING))
+ page_reporting_unregister(&vb->pr_dev_info);
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
+ unregister_oom_notifier(&vb->oom_nb);
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
virtio_balloon_unregister_shrinker(vb);
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);
+
+ if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
+ cancel_work_sync(&vb->report_free_page_work);
+ destroy_workqueue(vb->balloon_wq);
+ }
remove_common(vb);
#ifdef CONFIG_BALLOON_COMPACTION
@@ -708,7 +1108,18 @@
static int virtballoon_validate(struct virtio_device *vdev)
{
- __virtio_clear_bit(vdev, VIRTIO_F_IOMMU_PLATFORM);
+ /*
+ * Inform the hypervisor that our pages are poisoned or
+ * initialized. If we cannot do that then we should disable
+ * page reporting as it could potentially change the contents
+ * of our free pages.
+ */
+ if (!want_init_on_free() && !page_poisoning_enabled_static())
+ __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON);
+ else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON))
+ __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING);
+
+ __virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM);
return 0;
}
@@ -716,6 +1127,9 @@
VIRTIO_BALLOON_F_MUST_TELL_HOST,
VIRTIO_BALLOON_F_STATS_VQ,
VIRTIO_BALLOON_F_DEFLATE_ON_OOM,
+ VIRTIO_BALLOON_F_FREE_PAGE_HINT,
+ VIRTIO_BALLOON_F_PAGE_POISON,
+ VIRTIO_BALLOON_F_REPORTING,
};
static struct virtio_driver virtio_balloon_driver = {
--
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