diff options
| -rw-r--r-- | drivers/xen/balloon.c | 73 | ||||
| -rw-r--r-- | include/xen/balloon.h | 3 |
2 files changed, 70 insertions, 6 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 7497041d063..8c81cd24ed8 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -128,14 +128,17 @@ static void balloon_append(struct page *page) } /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ -static struct page *balloon_retrieve(void) +static struct page *balloon_retrieve(bool prefer_highmem) { struct page *page; if (list_empty(&ballooned_pages)) return NULL; - page = list_entry(ballooned_pages.next, struct page, lru); + if (prefer_highmem) + page = list_entry(ballooned_pages.prev, struct page, lru); + else + page = list_entry(ballooned_pages.next, struct page, lru); list_del(&page->lru); if (PageHighMem(page)) { @@ -233,7 +236,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages) return BP_EAGAIN; for (i = 0; i < rc; i++) { - page = balloon_retrieve(); + page = balloon_retrieve(false); BUG_ON(page == NULL); pfn = page_to_pfn(page); @@ -263,7 +266,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages) return BP_DONE; } -static enum bp_state decrease_reservation(unsigned long nr_pages) +static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) { enum bp_state state = BP_DONE; unsigned long pfn, i; @@ -279,7 +282,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages) nr_pages = ARRAY_SIZE(frame_list); for (i = 0; i < nr_pages; i++) { - if ((page = alloc_page(GFP_BALLOON)) == NULL) { + if ((page = alloc_page(gfp)) == NULL) { nr_pages = i; state = BP_EAGAIN; break; @@ -340,7 +343,7 @@ static void balloon_process(struct work_struct *work) state = increase_reservation(credit); if (credit < 0) - state = decrease_reservation(-credit); + state = decrease_reservation(-credit, GFP_BALLOON); state = update_schedule(state); @@ -366,6 +369,64 @@ void balloon_set_new_target(unsigned long target) } EXPORT_SYMBOL_GPL(balloon_set_new_target); +/** + * alloc_xenballooned_pages - get pages that have been ballooned out + * @nr_pages: Number of pages to get + * @pages: pages returned + * @return 0 on success, error otherwise + */ +int alloc_xenballooned_pages(int nr_pages, struct page** pages) +{ + int pgno = 0; + struct page* page; + mutex_lock(&balloon_mutex); + while (pgno < nr_pages) { + page = balloon_retrieve(true); + if (page) { + pages[pgno++] = page; + } else { + enum bp_state st; + st = decrease_reservation(nr_pages - pgno, GFP_HIGHUSER); + if (st != BP_DONE) + goto out_undo; + } + } + mutex_unlock(&balloon_mutex); + return 0; + out_undo: + while (pgno) + balloon_append(pages[--pgno]); + /* Free the memory back to the kernel soon */ + schedule_delayed_work(&balloon_worker, 0); + mutex_unlock(&balloon_mutex); + return -ENOMEM; +} +EXPORT_SYMBOL(alloc_xenballooned_pages); + +/** + * free_xenballooned_pages - return pages retrieved with get_ballooned_pages + * @nr_pages: Number of pages + * @pages: pages to return + */ +void free_xenballooned_pages(int nr_pages, struct page** pages) +{ + int i; + + mutex_lock(&balloon_mutex); + + for (i = 0; i < nr_pages; i++) { + if (pages[i]) + balloon_append(pages[i]); + } + + /* The balloon may be too large now. Shrink it if needed. */ + if (current_target() != balloon_stats.current_pages) + schedule_delayed_work(&balloon_worker, 0); + + mutex_unlock(&balloon_mutex); +} +EXPORT_SYMBOL(free_xenballooned_pages); + static int __init balloon_init(void) { unsigned long pfn, extra_pfn_end; diff --git a/include/xen/balloon.h b/include/xen/balloon.h index f72e4794ec7..a2b22f01a51 100644 --- a/include/xen/balloon.h +++ b/include/xen/balloon.h @@ -20,3 +20,6 @@ struct balloon_stats { extern struct balloon_stats balloon_stats; void balloon_set_new_target(unsigned long target); + +int alloc_xenballooned_pages(int nr_pages, struct page** pages); +void free_xenballooned_pages(int nr_pages, struct page** pages); |