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Subject: [RFC for Linux v4 1/2] virtio_balloon: Add VIRTIO_BALLOON_F_CONT_PAGES and inflate_cont_vq
This commit adds a new flag VIRTIO_BALLOON_F_CONT_PAGES to virtio_balloon.
Add it adds a vq inflate_cont_vq to inflate continuous pages.
When VIRTIO_BALLOON_F_CONT_PAGES is set, try to allocate continuous pages
and report them use inflate_cont_vq.
Signed-off-by: Hui Zhu <teawaterz@linux.alibaba.com>
---
drivers/virtio/virtio_balloon.c | 119 ++++++++++++++++++++++++++++++------
include/linux/balloon_compaction.h | 9 ++-
include/uapi/linux/virtio_balloon.h | 1 +
mm/balloon_compaction.c | 41 ++++++++++---
4 files changed, 142 insertions(+), 28 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 1f157d2..b89f566 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -42,6 +42,9 @@
(1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT))
#define VIRTIO_BALLOON_HINT_BLOCK_PAGES (1 << VIRTIO_BALLOON_HINT_BLOCK_ORDER)
+#define VIRTIO_BALLOON_INFLATE_MAX_ORDER min((int) (sizeof(__virtio32) * BITS_PER_BYTE - \
+ 1 - PAGE_SHIFT), (MAX_ORDER-1))
+
#ifdef CONFIG_BALLOON_COMPACTION
static struct vfsmount *balloon_mnt;
#endif
@@ -52,6 +55,7 @@ enum virtio_balloon_vq {
VIRTIO_BALLOON_VQ_STATS,
VIRTIO_BALLOON_VQ_FREE_PAGE,
VIRTIO_BALLOON_VQ_REPORTING,
+ VIRTIO_BALLOON_VQ_INFLATE_CONT,
VIRTIO_BALLOON_VQ_MAX
};
@@ -61,7 +65,7 @@ enum virtio_balloon_config_read {
struct virtio_balloon {
struct virtio_device *vdev;
- struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq;
+ struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq, *inflate_cont_vq;
/* Balloon's own wq for cpu-intensive work items */
struct workqueue_struct *balloon_wq;
@@ -126,6 +130,9 @@ struct virtio_balloon {
/* Free page reporting device */
struct virtqueue *reporting_vq;
struct page_reporting_dev_info pr_dev_info;
+
+ /* Current order of inflate continuous pages - VIRTIO_BALLOON_F_CONT_PAGES */
+ __u32 current_pages_order;
};
static struct virtio_device_id id_table[] = {
@@ -208,19 +215,59 @@ static void set_page_pfns(struct virtio_balloon *vb,
page_to_balloon_pfn(page) + i);
}
+static void set_page_pfns_order(struct virtio_balloon *vb,
+ __virtio32 pfns[], struct page *page,
+ unsigned int order)
+{
+ if (order == 0)
+ return set_page_pfns(vb, pfns, page);
+
+ /* Set the first pfn of the continuous pages. */
+ pfns[0] = cpu_to_virtio32(vb->vdev, page_to_balloon_pfn(page));
+ /* Set the size of the continuous pages. */
+ pfns[1] = PAGE_SIZE << order;
+}
+
static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
{
unsigned num_allocated_pages;
- unsigned num_pfns;
+ unsigned int num_pfns, pfn_per_alloc;
struct page *page;
LIST_HEAD(pages);
+ bool is_cont = vb->current_pages_order != 0;
- /* We can only do one array worth at a time. */
- num = min(num, ARRAY_SIZE(vb->pfns));
-
- for (num_pfns = 0; num_pfns < num;
- num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
- struct page *page = balloon_page_alloc();
+ if (is_cont)
+ pfn_per_alloc = 2;
+ else
+ pfn_per_alloc = VIRTIO_BALLOON_PAGES_PER_PAGE;
+
+ for (num_pfns = 0, num_allocated_pages = 0;
+ num_pfns < ARRAY_SIZE(vb->pfns) && num_allocated_pages < num;
+ num_pfns += pfn_per_alloc,
+ num_allocated_pages += VIRTIO_BALLOON_PAGES_PER_PAGE << vb->current_pages_order) {
+ struct page *page;
+
+ for (; vb->current_pages_order >= 0; vb->current_pages_order--) {
+ if (vb->current_pages_order &&
+ num - num_allocated_pages <
+ VIRTIO_BALLOON_PAGES_PER_PAGE << vb->current_pages_order)
+ continue;
+ page = balloon_pages_alloc(vb->current_pages_order);
+ if (page) {
+ /* If the first allocated page is not continuous pages,
+ * go back to transport page as signle page.
+ */
+ if (is_cont && num_pfns == 0 && !vb->current_pages_order) {
+ is_cont = false;
+ pfn_per_alloc = VIRTIO_BALLOON_PAGES_PER_PAGE;
+ }
+ set_page_private(page, vb->current_pages_order);
+ balloon_page_push(&pages, page);
+ break;
+ }
+ if (!vb->current_pages_order)
+ break;
+ }
if (!page) {
dev_info_ratelimited(&vb->vdev->dev,
@@ -230,8 +277,6 @@ static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
msleep(200);
break;
}
-
- balloon_page_push(&pages, page);
}
mutex_lock(&vb->balloon_lock);
@@ -239,20 +284,34 @@ static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
vb->num_pfns = 0;
while ((page = balloon_page_pop(&pages))) {
- balloon_page_enqueue(&vb->vb_dev_info, page);
+ unsigned int order = page_private(page);
+
+ set_page_private(page, 0);
+
+ /* Split the continuous pages because they will be freed
+ * by release_pages_balloon respectively.
+ */
+ if (order)
+ split_page(page, order);
+
+ balloon_pages_enqueue(&vb->vb_dev_info, page, order);
+
+ set_page_pfns_order(vb, vb->pfns + vb->num_pfns, page, order);
- 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);
- vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE;
+ adjust_managed_page_count(page, -(1 << order));
+ vb->num_pfns += pfn_per_alloc;
}
+ vb->num_pages += num_allocated_pages;
- num_allocated_pages = vb->num_pfns;
/* Did we get any? */
- if (vb->num_pfns != 0)
- tell_host(vb, vb->inflate_vq);
+ if (vb->num_pfns != 0) {
+ if (is_cont)
+ tell_host(vb, vb->inflate_cont_vq);
+ else
+ tell_host(vb, vb->inflate_vq);
+ }
mutex_unlock(&vb->balloon_lock);
return num_allocated_pages;
@@ -488,7 +547,7 @@ static void update_balloon_size_func(struct work_struct *work)
diff = towards_target(vb);
if (!diff)
- return;
+ goto stop_out;
if (diff > 0)
diff -= fill_balloon(vb, diff);
@@ -498,6 +557,11 @@ static void update_balloon_size_func(struct work_struct *work)
if (diff)
queue_work(system_freezable_wq, work);
+ else {
+stop_out:
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_CONT_PAGES))
+ vb->current_pages_order = VIRTIO_BALLOON_INFLATE_MAX_ORDER;
+ }
}
static int init_vqs(struct virtio_balloon *vb)
@@ -521,6 +585,8 @@ static int init_vqs(struct virtio_balloon *vb)
callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
names[VIRTIO_BALLOON_VQ_REPORTING] = NULL;
+ names[VIRTIO_BALLOON_VQ_INFLATE_CONT] = NULL;
+ callbacks[VIRTIO_BALLOON_VQ_INFLATE_CONT] = NULL;
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
names[VIRTIO_BALLOON_VQ_STATS] = "stats";
@@ -537,6 +603,11 @@ static int init_vqs(struct virtio_balloon *vb)
callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack;
}
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_CONT_PAGES)) {
+ names[VIRTIO_BALLOON_VQ_INFLATE_CONT] = "inflate_cont";
+ callbacks[VIRTIO_BALLOON_VQ_INFLATE_CONT] = balloon_ack;
+ }
+
err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX,
vqs, callbacks, names, NULL, NULL);
if (err)
@@ -572,6 +643,10 @@ static int init_vqs(struct virtio_balloon *vb)
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING))
vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING];
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_CONT_PAGES))
+ vb->inflate_cont_vq
+ = vqs[VIRTIO_BALLOON_VQ_INFLATE_CONT];
+
return 0;
}
@@ -997,6 +1072,11 @@ static int virtballoon_probe(struct virtio_device *vdev)
goto out_unregister_oom;
}
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_CONT_PAGES))
+ vb->current_pages_order = VIRTIO_BALLOON_INFLATE_MAX_ORDER;
+ else
+ vb->current_pages_order = 0;
+
virtio_device_ready(vdev);
if (towards_target(vb))
@@ -1131,6 +1211,7 @@ static unsigned int features[] = {
VIRTIO_BALLOON_F_FREE_PAGE_HINT,
VIRTIO_BALLOON_F_PAGE_POISON,
VIRTIO_BALLOON_F_REPORTING,
+ VIRTIO_BALLOON_F_CONT_PAGES,
};
static struct virtio_driver virtio_balloon_driver = {
diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index 338aa27..8180bbf 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -60,15 +60,22 @@ struct balloon_dev_info {
struct inode *inode;
};
-extern struct page *balloon_page_alloc(void);
+extern struct page *balloon_pages_alloc(unsigned int order);
extern void balloon_page_enqueue(struct balloon_dev_info *b_dev_info,
struct page *page);
+extern void balloon_pages_enqueue(struct balloon_dev_info *b_dev_info,
+ struct page *page, unsigned int order);
extern struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info);
extern size_t balloon_page_list_enqueue(struct balloon_dev_info *b_dev_info,
struct list_head *pages);
extern size_t balloon_page_list_dequeue(struct balloon_dev_info *b_dev_info,
struct list_head *pages, size_t n_req_pages);
+static inline struct page *balloon_page_alloc(void)
+{
+ return balloon_pages_alloc(0);
+}
+
static inline void balloon_devinfo_init(struct balloon_dev_info *balloon)
{
balloon->isolated_pages = 0;
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index dc3e656..4d0151a 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -37,6 +37,7 @@
#define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
#define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */
#define VIRTIO_BALLOON_F_REPORTING 5 /* Page reporting virtqueue */
+#define VIRTIO_BALLOON_F_CONT_PAGES 6 /* VQ to report continuous pages */
/* Size of a PFN in the balloon interface. */
#define VIRTIO_BALLOON_PFN_SHIFT 12
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 26de020..397d0b9 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -112,8 +112,8 @@ size_t balloon_page_list_dequeue(struct balloon_dev_info *b_dev_info,
EXPORT_SYMBOL_GPL(balloon_page_list_dequeue);
/*
- * balloon_page_alloc - allocates a new page for insertion into the balloon
- * page list.
+ * balloon_pages_alloc - allocates a new page for insertion into the balloon
+ * page list.
*
* Driver must call this function to properly allocate a new balloon page.
* Driver must call balloon_page_enqueue before definitively removing the page
@@ -121,14 +121,19 @@ EXPORT_SYMBOL_GPL(balloon_page_list_dequeue);
*
* Return: struct page for the allocated page or NULL on allocation failure.
*/
-struct page *balloon_page_alloc(void)
+struct page *balloon_pages_alloc(unsigned int order)
{
- struct page *page = alloc_page(balloon_mapping_gfp_mask() |
- __GFP_NOMEMALLOC | __GFP_NORETRY |
- __GFP_NOWARN);
- return page;
+ gfp_t gfp_mask;
+
+ if (order > 1)
+ gfp_mask = __GFP_RETRY_MAYFAIL;
+ else
+ gfp_mask = __GFP_NORETRY;
+
+ return alloc_pages(balloon_mapping_gfp_mask() |
+ gfp_mask | __GFP_NOMEMALLOC | __GFP_NOWARN, order);
}
-EXPORT_SYMBOL_GPL(balloon_page_alloc);
+EXPORT_SYMBOL_GPL(balloon_pages_alloc);
/*
* balloon_page_enqueue - inserts a new page into the balloon page list.
@@ -155,6 +160,26 @@ void balloon_page_enqueue(struct balloon_dev_info *b_dev_info,
EXPORT_SYMBOL_GPL(balloon_page_enqueue);
/*
+ * balloon_pages_enqueue - inserts continuous pages into the balloon page list.
+ */
+void balloon_pages_enqueue(struct balloon_dev_info *b_dev_info,
+ struct page *page, unsigned int order)
+{
+ unsigned long flags, pfn, last_pfn;
+
+ pfn = page_to_pfn(page);
+ last_pfn = pfn + (1 << order) - 1;
+
+ spin_lock_irqsave(&b_dev_info->pages_lock, flags);
+ for (; pfn <= last_pfn; pfn++) {
+ page = pfn_to_page(pfn);
+ balloon_page_enqueue_one(b_dev_info, page);
+ }
+ spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
+}
+EXPORT_SYMBOL_GPL(balloon_pages_enqueue);
+
+/*
* balloon_page_dequeue - removes a page from balloon's page list and returns
* its address to allow the driver to release the page.
* @b_dev_info: balloon device decriptor where we will grab a page from.
--
2.7.4
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