From: Konstantin Khlebnikov <[email protected]> This patch replaces checking AS_BALLOON_MAP in page->mapping->flags with PageBalloon which is stored directly in the struct page. All code of balloon_compaction now under CONFIG_MEMORY_BALLOON.
Signed-off-by: Konstantin Khlebnikov <[email protected]> --- drivers/virtio/Kconfig | 1 include/linux/balloon_compaction.h | 135 ++++++------------------------------ mm/Kconfig | 2 - mm/Makefile | 3 + mm/balloon_compaction.c | 7 +- mm/compaction.c | 9 +- mm/migrate.c | 6 +- mm/vmscan.c | 2 - 8 files changed, 39 insertions(+), 126 deletions(-) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index c6683f2..00b2286 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -25,6 +25,7 @@ config VIRTIO_PCI config VIRTIO_BALLOON tristate "Virtio balloon driver" depends on VIRTIO + select MEMORY_BALLOON ---help--- This driver supports increasing and decreasing the amount of memory within a KVM guest. diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h index 284fc1d..09f8c5a 100644 --- a/include/linux/balloon_compaction.h +++ b/include/linux/balloon_compaction.h @@ -46,6 +46,8 @@ #include <linux/gfp.h> #include <linux/err.h> +#ifdef CONFIG_MEMORY_BALLOON + /* * Balloon device information descriptor. * This struct is used to allow the common balloon compaction interface @@ -93,91 +95,6 @@ static inline void balloon_page_free(struct page *page) __free_page(page); } -#ifdef CONFIG_BALLOON_COMPACTION -extern bool balloon_page_isolate(struct page *page); -extern void balloon_page_putback(struct page *page); -extern int balloon_page_migrate(struct page *newpage, - struct page *page, enum migrate_mode mode); -extern struct address_space -*balloon_mapping_alloc(struct balloon_dev_info *b_dev_info, - const struct address_space_operations *a_ops); - -static inline void balloon_mapping_free(struct address_space *balloon_mapping) -{ - kfree(balloon_mapping); -} - -/* - * page_flags_cleared - helper to perform balloon @page ->flags tests. - * - * As balloon pages are obtained from buddy and we do not play with page->flags - * at driver level (exception made when we get the page lock for compaction), - * we can safely identify a ballooned page by checking if the - * PAGE_FLAGS_CHECK_AT_PREP page->flags are all cleared. This approach also - * helps us skip ballooned pages that are locked for compaction or release, thus - * mitigating their racy check at balloon_page_movable() - */ -static inline bool page_flags_cleared(struct page *page) -{ - return !(page->flags & PAGE_FLAGS_CHECK_AT_PREP); -} - -/* - * __is_movable_balloon_page - helper to perform @page mapping->flags tests - */ -static inline bool __is_movable_balloon_page(struct page *page) -{ - struct address_space *mapping = page->mapping; - return !PageAnon(page) && mapping_balloon(mapping); -} - -/* - * balloon_page_movable - test page->mapping->flags to identify balloon pages - * that can be moved by compaction/migration. - * - * This function is used at core compaction's page isolation scheme, therefore - * most pages exposed to it are not enlisted as balloon pages and so, to avoid - * undesired side effects like racing against __free_pages(), we cannot afford - * holding the page locked while testing page->mapping->flags here. - * - * As we might return false positives in the case of a balloon page being just - * released under us, the page->mapping->flags need to be re-tested later, - * under the proper page lock, at the functions that will be coping with the - * balloon page case. - */ -static inline bool balloon_page_movable(struct page *page) -{ - /* - * Before dereferencing and testing mapping->flags, let's make sure - * this is not a page that uses ->mapping in a different way - */ - if (page_flags_cleared(page) && !page_mapped(page) && - page_count(page) == 1) - return __is_movable_balloon_page(page); - - return false; -} - -/* - * isolated_balloon_page - identify an isolated balloon page on private - * compaction/migration page lists. - * - * After a compaction thread isolates a balloon page for migration, it raises - * the page refcount to prevent concurrent compaction threads from re-isolating - * the same page. For that reason putback_movable_pages(), or other routines - * that need to identify isolated balloon pages on private pagelists, cannot - * rely on balloon_page_movable() to accomplish the task. - */ -static inline bool isolated_balloon_page(struct page *page) -{ - /* Already isolated balloon pages, by default, have a raised refcount */ - if (page_flags_cleared(page) && !page_mapped(page) && - page_count(page) >= 2) - return __is_movable_balloon_page(page); - - return false; -} - /* * balloon_page_insert - insert a page into the balloon's page list and make * the page->mapping assignment accordingly. @@ -192,6 +109,8 @@ static inline void balloon_page_insert(struct page *page, struct address_space *mapping, struct list_head *head) { + __SetPageBalloon(page); + inc_zone_page_state(page, NR_BALLOON_PAGES); page->mapping = mapping; list_add(&page->lru, head); } @@ -206,10 +125,29 @@ static inline void balloon_page_insert(struct page *page, */ static inline void balloon_page_delete(struct page *page) { + __ClearPageBalloon(page); + dec_zone_page_state(page, NR_BALLOON_PAGES); page->mapping = NULL; list_del(&page->lru); } +#endif /* CONFIG_MEMORY_BALLOON */ + +#ifdef CONFIG_BALLOON_COMPACTION + +extern bool balloon_page_isolate(struct page *page); +extern void balloon_page_putback(struct page *page); +extern int balloon_page_migrate(struct page *newpage, + struct page *page, enum migrate_mode mode); +extern struct address_space +*balloon_mapping_alloc(struct balloon_dev_info *b_dev_info, + const struct address_space_operations *a_ops); + +static inline void balloon_mapping_free(struct address_space *balloon_mapping) +{ + kfree(balloon_mapping); +} + /* * balloon_page_device - get the b_dev_info descriptor for the balloon device * that enqueues the given page. @@ -246,33 +184,6 @@ static inline void balloon_mapping_free(struct address_space *balloon_mapping) return; } -static inline void balloon_page_insert(struct page *page, - struct address_space *mapping, - struct list_head *head) -{ - list_add(&page->lru, head); -} - -static inline void balloon_page_delete(struct page *page) -{ - list_del(&page->lru); -} - -static inline bool __is_movable_balloon_page(struct page *page) -{ - return false; -} - -static inline bool balloon_page_movable(struct page *page) -{ - return false; -} - -static inline bool isolated_balloon_page(struct page *page) -{ - return false; -} - static inline bool balloon_page_isolate(struct page *page) { return false; diff --git a/mm/Kconfig b/mm/Kconfig index 72e0db0..e09cf0a 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -237,7 +237,7 @@ config MEMORY_BALLOON config BALLOON_COMPACTION bool "Allow for balloon memory compaction/migration" def_bool y - depends on COMPACTION && VIRTIO_BALLOON + depends on COMPACTION && MEMORY_BALLOON help Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be diff --git a/mm/Makefile b/mm/Makefile index a96e3a1..b2f18dc 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -16,7 +16,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ util.o mmzone.o vmstat.o backing-dev.o \ mm_init.o mmu_context.o percpu.o slab_common.o \ - compaction.o balloon_compaction.o vmacache.o \ + compaction.o vmacache.o \ interval_tree.o list_lru.o workingset.o \ iov_iter.o $(mmu-y) @@ -64,3 +64,4 @@ obj-$(CONFIG_ZBUD) += zbud.o obj-$(CONFIG_ZSMALLOC) += zsmalloc.o obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o obj-$(CONFIG_CMA) += cma.o +obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index 6e45a50..a942081 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -239,8 +239,7 @@ bool balloon_page_isolate(struct page *page) * Prevent concurrent compaction threads from isolating * an already isolated balloon page by refcount check. */ - if (__is_movable_balloon_page(page) && - page_count(page) == 2) { + if (PageBalloon(page) && page_count(page) == 2) { __isolate_balloon_page(page); unlock_page(page); return true; @@ -261,7 +260,7 @@ void balloon_page_putback(struct page *page) */ lock_page(page); - if (__is_movable_balloon_page(page)) { + if (PageBalloon(page)) { __putback_balloon_page(page); /* drop the extra ref count taken for page isolation */ put_page(page); @@ -286,7 +285,7 @@ int balloon_page_migrate(struct page *newpage, */ BUG_ON(!trylock_page(newpage)); - if (WARN_ON(!__is_movable_balloon_page(page))) { + if (WARN_ON(!PageBalloon(page))) { dump_page(page, "not movable balloon page"); unlock_page(newpage); return rc; diff --git a/mm/compaction.c b/mm/compaction.c index ad58f73..7d9d92e 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -642,11 +642,10 @@ 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; - } + if (unlikely(PageBalloon(page)) && + balloon_page_isolate(page)) { + /* Successfully isolated */ + goto isolate_success; } continue; } diff --git a/mm/migrate.c b/mm/migrate.c index 57c94f9..a4939b1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -92,7 +92,7 @@ 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))) + if (unlikely(PageBalloon(page))) balloon_page_putback(page); else putback_lru_page(page); @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } } - if (unlikely(__is_movable_balloon_page(page))) { + if (unlikely(PageBalloon(page))) { /* * A ballooned page does not need any special attention from * physical to virtual reverse mapping procedures. @@ -952,6 +952,7 @@ static int unmap_and_move(new_page_t get_new_page, free_page_t put_new_page, rc = __unmap_and_move(page, newpage, force, mode); +#ifdef CONFIG_MEMORY_BALLOON if (unlikely(rc == MIGRATEPAGE_BALLOON_SUCCESS)) { /* * A ballooned page has been migrated already. @@ -963,6 +964,7 @@ static int unmap_and_move(new_page_t get_new_page, free_page_t put_new_page, balloon_page_free(page); return MIGRATEPAGE_SUCCESS; } +#endif out: if (rc != -EAGAIN) { /* diff --git a/mm/vmscan.c b/mm/vmscan.c index 1a71b8b..88dd901 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1160,7 +1160,7 @@ 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)) { + !PageBalloon(page)) { ClearPageActive(page); list_move(&page->lru, &clean_pages); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
