From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753893AbaIBM5s (ORCPT ); Tue, 2 Sep 2014 08:57:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28592 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752550AbaIBM5q (ORCPT ); Tue, 2 Sep 2014 08:57:46 -0400 Date: Tue, 2 Sep 2014 08:57:31 -0400 From: Rafael Aquini To: Konstantin Khlebnikov Cc: Andrew Morton , Konstantin Khlebnikov , Linux Kernel Mailing List , linux-mm@kvack.org, Andrey Ryabinin , Sasha Levin Subject: Re: [PATCH v2 5/6] mm/balloon_compaction: use common page ballooning Message-ID: <20140902125730.GF14419@t510.redhat.com> References: <20140830163834.29066.98205.stgit@zurg> <20140830164123.29066.26554.stgit@zurg> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140830164123.29066.26554.stgit@zurg> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 30, 2014 at 08:41:23PM +0400, Konstantin Khlebnikov wrote: > From: Konstantin Khlebnikov > > 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 > --- > 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 > #include > > +#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); > } > Acked-by: Rafael Aquini