diff options
| -rw-r--r-- | drivers/virtio/virtio_balloon.c | 54 | ||||
| -rw-r--r-- | include/linux/balloon_compaction.h | 54 | ||||
| -rw-r--r-- | include/uapi/linux/magic.h | 1 | ||||
| -rw-r--r-- | mm/balloon_compaction.c | 94 | ||||
| -rw-r--r-- | mm/compaction.c | 7 | ||||
| -rw-r--r-- | mm/migrate.c | 19 | ||||
| -rw-r--r-- | mm/vmscan.c | 2 |
7 files changed, 86 insertions, 145 deletions
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 476c0e3..88d5609 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -30,6 +30,7 @@ #include <linux/oom.h> #include <linux/wait.h> #include <linux/mm.h> +#include <linux/mount.h> /* * Balloon device works in 4K page units. So each page is pointed to by @@ -45,6 +46,10 @@ 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; @@ -488,8 +493,26 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, put_page(page); /* balloon reference */ - return MIGRATEPAGE_SUCCESS; + return 0; } + +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); +} + +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) @@ -519,9 +542,6 @@ static int virtballoon_probe(struct virtio_device *vdev) vb->vdev = vdev; balloon_devinfo_init(&vb->vb_dev_info); -#ifdef CONFIG_BALLOON_COMPACTION - vb->vb_dev_info.migratepage = virtballoon_migratepage; -#endif err = init_vqs(vb); if (err) @@ -531,13 +551,33 @@ static int virtballoon_probe(struct virtio_device *vdev) vb->nb.priority = VIRTBALLOON_OOM_NOTIFY_PRIORITY; err = register_oom_notifier(&vb->nb); if (err < 0) - goto out_oom_notify; + 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); return 0; -out_oom_notify: +out_del_vqs: vdev->config->del_vqs(vdev); out_free_vb: kfree(vb); @@ -571,6 +611,8 @@ static void virtballoon_remove(struct virtio_device *vdev) cancel_work_sync(&vb->update_balloon_stats_work); remove_common(vb); + if (vb->vb_dev_info.inode) + iput(vb->vb_dev_info.inode); kfree(vb); } diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 9b0a15d..504bd72 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -45,9 +45,11 @@ #define _LINUX_BALLOON_COMPACTION_H #include <linux/pagemap.h> #include <linux/page-flags.h> -#include <linux/migrate.h> +#include <linux/node.h> +#include <linux/compaction.h> #include <linux/gfp.h> #include <linux/err.h> +#include <linux/fs.h> /* * Balloon device information descriptor. @@ -62,6 +64,7 @@ struct balloon_dev_info { struct list_head pages; /* Pages enqueued & handled to Host */ int (*migratepage)(struct balloon_dev_info *, struct page *newpage, struct page *page, enum migrate_mode mode); + struct inode *inode; }; extern struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info); @@ -73,45 +76,19 @@ static inline void balloon_devinfo_init(struct balloon_dev_info *balloon) spin_lock_init(&balloon->pages_lock); INIT_LIST_HEAD(&balloon->pages); balloon->migratepage = NULL; + balloon->inode = NULL; } #ifdef CONFIG_BALLOON_COMPACTION -extern bool balloon_page_isolate(struct page *page); +extern const struct address_space_operations balloon_aops; +extern bool balloon_page_isolate(struct page *page, + isolate_mode_t mode); extern void balloon_page_putback(struct page *page); -extern int balloon_page_migrate(struct page *newpage, +extern int balloon_page_migrate(struct address_space *mapping, + struct page *newpage, struct page *page, enum migrate_mode mode); /* - * __is_movable_balloon_page - helper to perform @page PageBalloon tests - */ -static inline bool __is_movable_balloon_page(struct page *page) -{ - return PageBalloon(page); -} - -/* - * balloon_page_movable - test PageBalloon to identify balloon pages - * and PagePrivate to check that the page is not - * isolated and can be moved by compaction/migration. - * - * As we might return false positives in the case of a balloon page being just - * released under us, this need to be re-tested later, under the page lock. - */ -static inline bool balloon_page_movable(struct page *page) -{ - return PageBalloon(page) && PagePrivate(page); -} - -/* - * isolated_balloon_page - identify an isolated balloon page on private - * compaction/migration page lists. - */ -static inline bool isolated_balloon_page(struct page *page) -{ - return PageBalloon(page); -} - -/* * balloon_page_insert - insert a page into the balloon's page list and make * the page->private assignment accordingly. * @balloon : pointer to balloon device @@ -124,7 +101,7 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon, struct page *page) { __SetPageBalloon(page); - SetPagePrivate(page); + __SetPageMovable(page, balloon->inode->i_mapping); set_page_private(page, (unsigned long)balloon); list_add(&page->lru, &balloon->pages); } @@ -140,11 +117,14 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon, static inline void balloon_page_delete(struct page *page) { __ClearPageBalloon(page); + __ClearPageMovable(page); set_page_private(page, 0); - if (PagePrivate(page)) { - ClearPagePrivate(page); + /* + * No touch page.lru field once @page has been isolated + * because VM is using the field. + */ + if (!PageIsolated(page)) list_del(&page->lru); - } } /* diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index 546b388..d829ce6 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -80,5 +80,6 @@ #define BPF_FS_MAGIC 0xcafe4a11 /* Since UDF 2.01 is ISO 13346 based... */ #define UDF_SUPER_MAGIC 0x15013346 +#define BALLOON_KVM_MAGIC 0x13661366 #endif /* __LINUX_MAGIC_H__ */ diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index 57b3e9b..da91df5 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -70,7 +70,7 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info) */ if (trylock_page(page)) { #ifdef CONFIG_BALLOON_COMPACTION - if (!PagePrivate(page)) { + if (PageIsolated(page)) { /* raced with isolation */ unlock_page(page); continue; @@ -106,110 +106,50 @@ EXPORT_SYMBOL_GPL(balloon_page_dequeue); #ifdef CONFIG_BALLOON_COMPACTION -static inline void __isolate_balloon_page(struct page *page) +bool balloon_page_isolate(struct page *page, isolate_mode_t mode) + { struct balloon_dev_info *b_dev_info = balloon_page_device(page); unsigned long flags; spin_lock_irqsave(&b_dev_info->pages_lock, flags); - ClearPagePrivate(page); list_del(&page->lru); b_dev_info->isolated_pages++; spin_unlock_irqrestore(&b_dev_info->pages_lock, flags); + + return true; } -static inline void __putback_balloon_page(struct page *page) +void balloon_page_putback(struct page *page) { struct balloon_dev_info *b_dev_info = balloon_page_device(page); unsigned long flags; spin_lock_irqsave(&b_dev_info->pages_lock, flags); - SetPagePrivate(page); list_add(&page->lru, &b_dev_info->pages); b_dev_info->isolated_pages--; spin_unlock_irqrestore(&b_dev_info->pages_lock, flags); } -/* __isolate_lru_page() counterpart for a ballooned page */ -bool balloon_page_isolate(struct page *page) -{ - /* - * Avoid burning cycles with pages that are yet under __free_pages(), - * or just got freed under us. - * - * In case we 'win' a race for a balloon page being freed under us and - * raise its refcount preventing __free_pages() from doing its job - * the put_page() at the end of this block will take care of - * release this page, thus avoiding a nasty leakage. - */ - if (likely(get_page_unless_zero(page))) { - /* - * As balloon pages are not isolated from LRU lists, concurrent - * compaction threads can race against page migration functions - * as well as race against the balloon driver releasing a page. - * - * In order to avoid having an already isolated balloon page - * being (wrongly) re-isolated while it is under migration, - * or to avoid attempting to isolate pages being released by - * the balloon driver, lets be sure we have the page lock - * before proceeding with the balloon page isolation steps. - */ - if (likely(trylock_page(page))) { - /* - * A ballooned page, by default, has PagePrivate set. - * Prevent concurrent compaction threads from isolating - * an already isolated balloon page by clearing it. - */ - if (balloon_page_movable(page)) { - __isolate_balloon_page(page); - unlock_page(page); - return true; - } - unlock_page(page); - } - put_page(page); - } - return false; -} - -/* putback_lru_page() counterpart for a ballooned page */ -void balloon_page_putback(struct page *page) -{ - /* - * 'lock_page()' stabilizes the page and prevents races against - * concurrent isolation threads attempting to re-isolate it. - */ - lock_page(page); - - if (__is_movable_balloon_page(page)) { - __putback_balloon_page(page); - /* drop the extra ref count taken for page isolation */ - put_page(page); - } else { - WARN_ON(1); - dump_page(page, "not movable balloon page"); - } - unlock_page(page); -} /* move_to_new_page() counterpart for a ballooned page */ -int balloon_page_migrate(struct page *newpage, - struct page *page, enum migrate_mode mode) +int balloon_page_migrate(struct address_space *mapping, + struct page *newpage, struct page *page, + enum migrate_mode mode) { struct balloon_dev_info *balloon = balloon_page_device(page); - int rc = -EAGAIN; VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); - if (WARN_ON(!__is_movable_balloon_page(page))) { - dump_page(page, "not movable balloon page"); - return rc; - } + return balloon->migratepage(balloon, newpage, page, mode); +} - if (balloon && balloon->migratepage) - rc = balloon->migratepage(balloon, newpage, page, mode); +const struct address_space_operations balloon_aops = { + .migratepage = balloon_page_migrate, + .isolate_page = balloon_page_isolate, + .putback_page = balloon_page_putback, +}; +EXPORT_SYMBOL_GPL(balloon_aops); - return rc; -} #endif /* CONFIG_BALLOON_COMPACTION */ diff --git a/mm/compaction.c b/mm/compaction.c index fe95d8d..d855206 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -791,13 +791,6 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, * Skip any other type of page */ if (!PageLRU(page)) { - if (unlikely(balloon_page_movable(page))) { - if (balloon_page_isolate(page)) { - /* Successfully isolated */ - goto isolate_success; - } - } - /* * __PageMovable can return false positive so we need * to verify it under page_lock. diff --git a/mm/migrate.c b/mm/migrate.c index 8119fdc..f278005 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -170,14 +170,12 @@ void putback_movable_pages(struct list_head *l) list_del(&page->lru); dec_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); - if (unlikely(isolated_balloon_page(page))) { - balloon_page_putback(page); /* * We isolated non-lru movable page so here we can use * __PageMovable because LRU page's mapping cannot have * PAGE_MAPPING_MOVABLE. */ - } else if (unlikely(__PageMovable(page))) { + if (unlikely(__PageMovable(page))) { VM_BUG_ON_PAGE(!PageIsolated(page), page); lock_page(page); if (PageMovable(page)) @@ -992,18 +990,6 @@ static int __unmap_and_move(struct page *page, struct page *newpage, if (unlikely(!trylock_page(newpage))) goto out_unlock; - if (unlikely(isolated_balloon_page(page))) { - /* - * A ballooned page does not need any special attention from - * physical to virtual reverse mapping procedures. - * Skip any attempt to unmap PTEs or to remap swap cache, - * in order to avoid burning cycles at rmap level, and perform - * the page migration right away (proteced by page lock). - */ - rc = balloon_page_migrate(newpage, page, mode); - goto out_unlock_both; - } - if (unlikely(!is_lru)) { rc = move_to_new_page(newpage, page, mode); goto out_unlock_both; @@ -1058,8 +1044,7 @@ out: * list in here. */ if (rc == MIGRATEPAGE_SUCCESS) { - if (unlikely(__is_movable_balloon_page(newpage) || - __PageMovable(newpage))) + if (unlikely(__PageMovable(newpage))) put_page(newpage); else putback_lru_page(newpage); diff --git a/mm/vmscan.c b/mm/vmscan.c index c4a2f451..93ba337 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1254,7 +1254,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone, list_for_each_entry_safe(page, next, page_list, lru) { if (page_is_file_cache(page) && !PageDirty(page) && - !isolated_balloon_page(page)) { + !__PageMovable(page)) { ClearPageActive(page); list_move(&page->lru, &clean_pages); } |
