#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/balloon_compaction.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 (PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT)
+#define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT)
+#define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256
struct virtio_balloon
{
/* 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.
+ * 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 list_head pages;
+ 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;
- u32 pfns[256];
+ u32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX];
/* Memory statistics */
int need_stats_update;
static void fill_balloon(struct virtio_balloon *vb, size_t num)
{
+ 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);
for (vb->num_pfns = 0; vb->num_pfns < num;
vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
- struct page *page = alloc_page(GFP_HIGHUSER | __GFP_NORETRY |
- __GFP_NOMEMALLOC | __GFP_NOWARN);
+ struct page *page = balloon_page_enqueue(vb_dev_info);
+
if (!page) {
if (printk_ratelimit())
dev_printk(KERN_INFO, &vb->vdev->dev,
- "Out of puff! Can't get %zu pages\n",
- num);
+ "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->pfns + vb->num_pfns, page);
vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
totalram_pages--;
- list_add(&page->lru, &vb->pages);
}
- /* Didn't get any? Oh well. */
- if (vb->num_pfns == 0)
- return;
-
- tell_host(vb, vb->inflate_vq);
+ /* Did we get any? */
+ if (vb->num_pfns != 0)
+ tell_host(vb, vb->inflate_vq);
+ mutex_unlock(&vb->balloon_lock);
}
static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
/* Find pfns pointing at start of each page, get pages and free them. */
for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
- __free_page(balloon_pfn_to_page(pfns[i]));
+ balloon_page_free(balloon_pfn_to_page(pfns[i]));
totalram_pages++;
}
}
static void leak_balloon(struct virtio_balloon *vb, size_t num)
{
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);
for (vb->num_pfns = 0; vb->num_pfns < num;
vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
- page = list_first_entry(&vb->pages, struct page, lru);
- list_del(&page->lru);
+ page = balloon_page_dequeue(vb_dev_info);
+ if (!page)
+ break;
set_page_pfns(vb->pfns + vb->num_pfns, page);
vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
}
* is true, we *have* to do it in this order
*/
tell_host(vb, vb->deflate_vq);
+ mutex_unlock(&vb->balloon_lock);
release_pages_by_pfn(vb->pfns, vb->num_pfns);
}
return 0;
}
+static const struct address_space_operations virtio_balloon_aops;
+#ifdef CONFIG_BALLOON_COMPACTION
+/*
+ * virtballoon_migratepage - perform the balloon page migration on behalf of
+ * a compation thread. (called under page lock)
+ * @mapping: the page->mapping which will be assigned to the new migrated page.
+ * @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
+ */
+int virtballoon_migratepage(struct address_space *mapping,
+ struct page *newpage, struct page *page, enum migrate_mode mode)
+{
+ struct balloon_dev_info *vb_dev_info = balloon_page_device(page);
+ struct virtio_balloon *vb;
+ unsigned long flags;
+
+ BUG_ON(!vb_dev_info);
+
+ vb = vb_dev_info->balloon_device;
+
+ /*
+ * 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;
+
+ /* balloon's page migration 1st step -- inflate "newpage" */
+ spin_lock_irqsave(&vb_dev_info->pages_lock, flags);
+ balloon_page_insert(newpage, mapping, &vb_dev_info->pages);
+ vb_dev_info->isolated_pages--;
+ spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags);
+ vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
+ set_page_pfns(vb->pfns, newpage);
+ tell_host(vb, vb->inflate_vq);
+
+ /*
+ * balloon's page migration 2nd step -- deflate "page"
+ *
+ * It's safe to delete page->lru here because this page is at
+ * an isolated migration list, and this step is expected to happen here
+ */
+ balloon_page_delete(page);
+ vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
+ set_page_pfns(vb->pfns, page);
+ tell_host(vb, vb->deflate_vq);
+
+ mutex_unlock(&vb->balloon_lock);
+
+ return MIGRATEPAGE_BALLOON_SUCCESS;
+}
+
+/* define the balloon_mapping->a_ops callback to allow balloon page migration */
+static const struct address_space_operations virtio_balloon_aops = {
+ .migratepage = virtballoon_migratepage,
+};
+#endif /* CONFIG_BALLOON_COMPACTION */
+
static int virtballoon_probe(struct virtio_device *vdev)
{
struct virtio_balloon *vb;
+ struct address_space *vb_mapping;
+ struct balloon_dev_info *vb_devinfo;
int err;
vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL);
goto out;
}
- INIT_LIST_HEAD(&vb->pages);
vb->num_pages = 0;
+ mutex_init(&vb->balloon_lock);
init_waitqueue_head(&vb->config_change);
init_waitqueue_head(&vb->acked);
vb->vdev = vdev;
vb->need_stats_update = 0;
+ vb_devinfo = balloon_devinfo_alloc(vb);
+ if (IS_ERR(vb_devinfo)) {
+ err = PTR_ERR(vb_devinfo);
+ goto out_free_vb;
+ }
+
+ vb_mapping = balloon_mapping_alloc(vb_devinfo,
+ (balloon_compaction_check()) ?
+ &virtio_balloon_aops : NULL);
+ if (IS_ERR(vb_mapping)) {
+ /*
+ * IS_ERR(vb_mapping) && PTR_ERR(vb_mapping) == -EOPNOTSUPP
+ * This means !CONFIG_BALLOON_COMPACTION, otherwise we get off.
+ */
+ err = PTR_ERR(vb_mapping);
+ if (err != -EOPNOTSUPP)
+ goto out_free_vb_devinfo;
+ }
+
+ vb->vb_dev_info = vb_devinfo;
+
err = init_vqs(vb);
if (err)
- goto out_free_vb;
+ goto out_free_vb_mapping;
vb->thread = kthread_run(balloon, vb, "vballoon");
if (IS_ERR(vb->thread)) {
out_del_vqs:
vdev->config->del_vqs(vdev);
+out_free_vb_mapping:
+ balloon_mapping_free(vb_mapping);
+out_free_vb_devinfo:
+ balloon_devinfo_free(vb_devinfo);
out_free_vb:
kfree(vb);
out:
kthread_stop(vb->thread);
remove_common(vb);
+ balloon_mapping_free(vb->vb_dev_info->mapping);
+ balloon_devinfo_free(vb->vb_dev_info);
kfree(vb);
}
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff