diff options
| -rw-r--r-- | drivers/misc/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/misc/vmw_balloon.c | 301 |
2 files changed, 264 insertions, 38 deletions
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 3fa4adeaf8a2..6b0417b2fbc4 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -386,6 +386,7 @@ config SPEAR13XX_PCIE_GADGET config VMWARE_BALLOON tristate "VMware Balloon Driver" depends on VMWARE_VMCI && X86 && HYPERVISOR_GUEST + select MEMORY_BALLOON help This is VMware physical memory management driver which acts like a "balloon" that can be inflated to reclaim physical pages diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index ad807d5a3141..2136f6ad97d3 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -28,6 +28,8 @@ #include <linux/rwsem.h> #include <linux/slab.h> #include <linux/spinlock.h> +#include <linux/mount.h> +#include <linux/balloon_compaction.h> #include <linux/vmw_vmci_defs.h> #include <linux/vmw_vmci_api.h> #include <asm/hypervisor.h> @@ -38,25 +40,11 @@ MODULE_ALIAS("dmi:*:svnVMware*:*"); MODULE_ALIAS("vmware_vmmemctl"); MODULE_LICENSE("GPL"); -/* - * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't allow wait - * (__GFP_RECLAIM) for huge page allocations. Use __GFP_NOWARN, to suppress page - * allocation failure warnings. Disallow access to emergency low-memory pools. - */ -#define VMW_HUGE_PAGE_ALLOC_FLAGS (__GFP_HIGHMEM|__GFP_NOWARN| \ - __GFP_NOMEMALLOC) - -/* - * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We allow lightweight - * reclamation (__GFP_NORETRY). Use __GFP_NOWARN, to suppress page allocation - * failure warnings. Disallow access to emergency low-memory pools. - */ -#define VMW_PAGE_ALLOC_FLAGS (__GFP_HIGHMEM|__GFP_NOWARN| \ - __GFP_NOMEMALLOC|__GFP_NORETRY) - -/* Maximum number of refused pages we accumulate during inflation cycle */ #define VMW_BALLOON_MAX_REFUSED 16 +/* Magic number for the balloon mount-point */ +#define BALLOON_VMW_MAGIC 0x0ba11007 + /* * Hypervisor communication port definitions. */ @@ -247,11 +235,6 @@ struct vmballoon_ctl { enum vmballoon_op op; }; -struct vmballoon_page_size { - /* list of reserved physical pages */ - struct list_head pages; -}; - /** * struct vmballoon_batch_entry - a batch entry for lock or unlock. * @@ -266,8 +249,6 @@ struct vmballoon_batch_entry { } __packed; struct vmballoon { - struct vmballoon_page_size page_sizes[VMW_BALLOON_NUM_PAGE_SIZES]; - /** * @max_page_size: maximum supported page size for ballooning. * @@ -348,9 +329,21 @@ struct vmballoon { struct dentry *dbg_entry; #endif + /** + * @b_dev_info: balloon device information descriptor. + */ + struct balloon_dev_info b_dev_info; + struct delayed_work dwork; /** + * @huge_pages - list of the inflated 2MB pages. + * + * Protected by @b_dev_info.pages_lock . + */ + struct list_head huge_pages; + + /** * @vmci_doorbell. * * Protected by @conf_sem. @@ -643,10 +636,10 @@ static int vmballoon_alloc_page_list(struct vmballoon *b, for (i = 0; i < req_n_pages; i++) { if (ctl->page_size == VMW_BALLOON_2M_PAGE) - page = alloc_pages(VMW_HUGE_PAGE_ALLOC_FLAGS, - VMW_BALLOON_2M_ORDER); + page = alloc_pages(__GFP_HIGHMEM|__GFP_NOWARN| + __GFP_NOMEMALLOC, VMW_BALLOON_2M_ORDER); else - page = alloc_page(VMW_PAGE_ALLOC_FLAGS); + page = balloon_page_alloc(); /* Update statistics */ vmballoon_stats_page_inc(b, VMW_BALLOON_PAGE_STAT_ALLOC, @@ -961,9 +954,22 @@ static void vmballoon_enqueue_page_list(struct vmballoon *b, unsigned int *n_pages, enum vmballoon_page_size_type page_size) { - struct vmballoon_page_size *page_size_info = &b->page_sizes[page_size]; + unsigned long flags; + + if (page_size == VMW_BALLOON_4K_PAGE) { + balloon_page_list_enqueue(&b->b_dev_info, pages); + } else { + /* + * Keep the huge pages in a local list which is not available + * for the balloon compaction mechanism. + */ + spin_lock_irqsave(&b->b_dev_info.pages_lock, flags); + list_splice_init(pages, &b->huge_pages); + __count_vm_events(BALLOON_INFLATE, *n_pages * + vmballoon_page_in_frames(VMW_BALLOON_2M_PAGE)); + spin_unlock_irqrestore(&b->b_dev_info.pages_lock, flags); + } - list_splice_init(pages, &page_size_info->pages); *n_pages = 0; } @@ -986,15 +992,28 @@ static void vmballoon_dequeue_page_list(struct vmballoon *b, enum vmballoon_page_size_type page_size, unsigned int n_req_pages) { - struct vmballoon_page_size *page_size_info = &b->page_sizes[page_size]; struct page *page, *tmp; unsigned int i = 0; + unsigned long flags; - list_for_each_entry_safe(page, tmp, &page_size_info->pages, lru) { + /* In the case of 4k pages, use the compaction infrastructure */ + if (page_size == VMW_BALLOON_4K_PAGE) { + *n_pages = balloon_page_list_dequeue(&b->b_dev_info, pages, + n_req_pages); + return; + } + + /* 2MB pages */ + spin_lock_irqsave(&b->b_dev_info.pages_lock, flags); + list_for_each_entry_safe(page, tmp, &b->huge_pages, lru) { list_move(&page->lru, pages); if (++i == n_req_pages) break; } + + __count_vm_events(BALLOON_DEFLATE, + i * vmballoon_page_in_frames(VMW_BALLOON_2M_PAGE)); + spin_unlock_irqrestore(&b->b_dev_info.pages_lock, flags); *n_pages = i; } @@ -1552,9 +1571,204 @@ static inline void vmballoon_debugfs_exit(struct vmballoon *b) #endif /* CONFIG_DEBUG_FS */ + +#ifdef CONFIG_BALLOON_COMPACTION + +static struct dentry *vmballoon_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-vmware:", NULL, &ops, + BALLOON_VMW_MAGIC); +} + +static struct file_system_type vmballoon_fs = { + .name = "balloon-vmware", + .mount = vmballoon_mount, + .kill_sb = kill_anon_super, +}; + +static struct vfsmount *vmballoon_mnt; + +/** + * vmballoon_migratepage() - migrates a balloon page. + * @b_dev_info: balloon device information descriptor. + * @newpage: the page to which @page should be migrated. + * @page: a ballooned page that should be migrated. + * @mode: migration mode, ignored. + * + * This function is really open-coded, but that is according to the interface + * that balloon_compaction provides. + * + * Return: zero on success, -EAGAIN when migration cannot be performed + * momentarily, and -EBUSY if migration failed and should be retried + * with that specific page. + */ +static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info, + struct page *newpage, struct page *page, + enum migrate_mode mode) +{ + unsigned long status, flags; + struct vmballoon *b; + int ret; + + b = container_of(b_dev_info, struct vmballoon, b_dev_info); + + /* + * If the semaphore is taken, there is ongoing configuration change + * (i.e., balloon reset), so try again. + */ + if (!down_read_trylock(&b->conf_sem)) + return -EAGAIN; + + spin_lock(&b->comm_lock); + /* + * We must start by deflating and not inflating, as otherwise the + * hypervisor may tell us that it has enough memory and the new page is + * not needed. Since the old page is isolated, we cannot use the list + * interface to unlock it, as the LRU field is used for isolation. + * Instead, we use the native interface directly. + */ + vmballoon_add_page(b, 0, page); + status = vmballoon_lock_op(b, 1, VMW_BALLOON_4K_PAGE, + VMW_BALLOON_DEFLATE); + + if (status == VMW_BALLOON_SUCCESS) + status = vmballoon_status_page(b, 0, &page); + + /* + * If a failure happened, let the migration mechanism know that it + * should not retry. + */ + if (status != VMW_BALLOON_SUCCESS) { + spin_unlock(&b->comm_lock); + ret = -EBUSY; + goto out_unlock; + } + + /* + * The page is isolated, so it is safe to delete it without holding + * @pages_lock . We keep holding @comm_lock since we will need it in a + * second. + */ + balloon_page_delete(page); + + put_page(page); + + /* Inflate */ + vmballoon_add_page(b, 0, newpage); + status = vmballoon_lock_op(b, 1, VMW_BALLOON_4K_PAGE, + VMW_BALLOON_INFLATE); + + if (status == VMW_BALLOON_SUCCESS) + status = vmballoon_status_page(b, 0, &newpage); + + spin_unlock(&b->comm_lock); + + if (status != VMW_BALLOON_SUCCESS) { + /* + * A failure happened. While we can deflate the page we just + * inflated, this deflation can also encounter an error. Instead + * we will decrease the size of the balloon to reflect the + * change and report failure. + */ + atomic64_dec(&b->size); + ret = -EBUSY; + } else { + /* + * Success. Take a reference for the page, and we will add it to + * the list after acquiring the lock. + */ + get_page(newpage); + ret = MIGRATEPAGE_SUCCESS; + } + + /* Update the balloon list under the @pages_lock */ + spin_lock_irqsave(&b->b_dev_info.pages_lock, flags); + + /* + * On inflation success, we already took a reference for the @newpage. + * If we succeed just insert it to the list and update the statistics + * under the lock. + */ + if (ret == MIGRATEPAGE_SUCCESS) { + balloon_page_insert(&b->b_dev_info, newpage); + __count_vm_event(BALLOON_MIGRATE); + } + + /* + * We deflated successfully, so regardless to the inflation success, we + * need to reduce the number of isolated_pages. + */ + b->b_dev_info.isolated_pages--; + spin_unlock_irqrestore(&b->b_dev_info.pages_lock, flags); + +out_unlock: + up_read(&b->conf_sem); + return ret; +} + +/** + * vmballoon_compaction_deinit() - removes compaction related data. + * + * @b: pointer to the balloon. + */ +static void vmballoon_compaction_deinit(struct vmballoon *b) +{ + if (!IS_ERR(b->b_dev_info.inode)) + iput(b->b_dev_info.inode); + + b->b_dev_info.inode = NULL; + kern_unmount(vmballoon_mnt); + vmballoon_mnt = NULL; +} + +/** + * vmballoon_compaction_init() - initialized compaction for the balloon. + * + * @b: pointer to the balloon. + * + * If during the initialization a failure occurred, this function does not + * perform cleanup. The caller must call vmballoon_compaction_deinit() in this + * case. + * + * Return: zero on success or error code on failure. + */ +static __init int vmballoon_compaction_init(struct vmballoon *b) +{ + vmballoon_mnt = kern_mount(&vmballoon_fs); + if (IS_ERR(vmballoon_mnt)) + return PTR_ERR(vmballoon_mnt); + + b->b_dev_info.migratepage = vmballoon_migratepage; + b->b_dev_info.inode = alloc_anon_inode(vmballoon_mnt->mnt_sb); + + if (IS_ERR(b->b_dev_info.inode)) + return PTR_ERR(b->b_dev_info.inode); + + b->b_dev_info.inode->i_mapping->a_ops = &balloon_aops; + return 0; +} + +#else /* CONFIG_BALLOON_COMPACTION */ + +static void vmballoon_compaction_deinit(struct vmballoon *b) +{ +} + +static int vmballoon_compaction_init(struct vmballoon *b) +{ + return 0; +} + +#endif /* CONFIG_BALLOON_COMPACTION */ + static int __init vmballoon_init(void) { - enum vmballoon_page_size_type page_size; int error; /* @@ -1564,17 +1778,22 @@ static int __init vmballoon_init(void) if (x86_hyper_type != X86_HYPER_VMWARE) return -ENODEV; - for (page_size = VMW_BALLOON_4K_PAGE; - page_size <= VMW_BALLOON_LAST_SIZE; page_size++) - INIT_LIST_HEAD(&balloon.page_sizes[page_size].pages); - - INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work); error = vmballoon_debugfs_init(&balloon); if (error) - return error; + goto fail; + /* + * Initialization of compaction must be done after the call to + * balloon_devinfo_init() . + */ + balloon_devinfo_init(&balloon.b_dev_info); + error = vmballoon_compaction_init(&balloon); + if (error) + goto fail; + + INIT_LIST_HEAD(&balloon.huge_pages); spin_lock_init(&balloon.comm_lock); init_rwsem(&balloon.conf_sem); balloon.vmci_doorbell = VMCI_INVALID_HANDLE; @@ -1585,6 +1804,9 @@ static int __init vmballoon_init(void) queue_delayed_work(system_freezable_wq, &balloon.dwork, 0); return 0; +fail: + vmballoon_compaction_deinit(&balloon); + return error; } /* @@ -1609,5 +1831,8 @@ static void __exit vmballoon_exit(void) */ vmballoon_send_start(&balloon, 0); vmballoon_pop(&balloon); + + /* Only once we popped the balloon, compaction can be deinit */ + vmballoon_compaction_deinit(&balloon); } module_exit(vmballoon_exit); |