On Mon, Nov 19, 2018 at 11:16:10AM +0100, David Hildenbrand wrote: > PG_balloon was introduced to implement page migration/compaction for pages > inflated in virtio-balloon. Nowadays, it is only a marker that a page is > part of virtio-balloon and therefore logically offline. > > We also want to make use of this flag in other balloon drivers - for > inflated pages or when onlining a section but keeping some pages offline > (e.g. used right now by XEN and Hyper-V via set_online_page_callback()). > > We are going to expose this flag to dump tools like makedumpfile. But > instead of exposing PG_balloon, let's generalize the concept of marking > pages as logically offline, so it can be reused for other purposes > later on. > > Rename PG_balloon to PG_offline. This is an indicator that the page is > logically offline, the content stale and that it should not be touched > (e.g. a hypervisor would have to allocate backing storage in order for the > guest to dump an unused page). We can then e.g. exclude such pages from > dumps. > > We replace and reuse KPF_BALLOON (23), as this shouldn't really harm > (and for now the semantics stay the same). In following patches, we will > make use of this bit also in other balloon drivers. While at it, document > PGTABLE. > > Cc: Jonathan Corbet <corbet@xxxxxxx> > Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> > Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Christian Hansen <chansen3@xxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx> > Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > Cc: Miles Chen <miles.chen@xxxxxxxxxxxx> > Cc: David Rientjes <rientjes@xxxxxxxxxx> > Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx> > Cc: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx> > Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> > --- > Documentation/admin-guide/mm/pagemap.rst | 9 ++++++--- > fs/proc/page.c | 4 ++-- > include/linux/balloon_compaction.h | 8 ++++---- > include/linux/page-flags.h | 11 +++++++---- > include/uapi/linux/kernel-page-flags.h | 2 +- > tools/vm/page-types.c | 2 +- > 6 files changed, 21 insertions(+), 15 deletions(-) > > diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst > index 3f7bade2c231..340a5aee9b80 100644 > --- a/Documentation/admin-guide/mm/pagemap.rst > +++ b/Documentation/admin-guide/mm/pagemap.rst > @@ -75,9 +75,10 @@ number of times a page is mapped. > 20. NOPAGE > 21. KSM > 22. THP > - 23. BALLOON > + 23. OFFLINE > 24. ZERO_PAGE > 25. IDLE > + 26. PGTABLE > > * ``/proc/kpagecgroup``. This file contains a 64-bit inode number of the > memory cgroup each page is charged to, indexed by PFN. Only available when > @@ -118,8 +119,8 @@ Short descriptions to the page flags > identical memory pages dynamically shared between one or more processes > 22 - THP > contiguous pages which construct transparent hugepages > -23 - BALLOON > - balloon compaction page > +23 - OFFLINE > + page is logically offline > 24 - ZERO_PAGE > zero page for pfn_zero or huge_zero page > 25 - IDLE > @@ -128,6 +129,8 @@ Short descriptions to the page flags > Note that this flag may be stale in case the page was accessed via > a PTE. To make sure the flag is up-to-date one has to read > ``/sys/kernel/mm/page_idle/bitmap`` first. > +26 - PGTABLE > + page is in use as a page table > > IO related page flags > --------------------- > diff --git a/fs/proc/page.c b/fs/proc/page.c > index 6c517b11acf8..378401af4d9d 100644 > --- a/fs/proc/page.c > +++ b/fs/proc/page.c > @@ -152,8 +152,8 @@ u64 stable_page_flags(struct page *page) > else if (page_count(page) == 0 && is_free_buddy_page(page)) > u |= 1 << KPF_BUDDY; > > - if (PageBalloon(page)) > - u |= 1 << KPF_BALLOON; > + if (PageOffline(page)) > + u |= 1 << KPF_OFFLINE; > if (PageTable(page)) > u |= 1 << KPF_PGTABLE; > > diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h > index cbe50da5a59d..f111c780ef1d 100644 > --- a/include/linux/balloon_compaction.h > +++ b/include/linux/balloon_compaction.h > @@ -95,7 +95,7 @@ extern int balloon_page_migrate(struct address_space *mapping, > static inline void balloon_page_insert(struct balloon_dev_info *balloon, > struct page *page) > { > - __SetPageBalloon(page); > + __SetPageOffline(page); > __SetPageMovable(page, balloon->inode->i_mapping); > set_page_private(page, (unsigned long)balloon); > list_add(&page->lru, &balloon->pages); > @@ -111,7 +111,7 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon, > */ > static inline void balloon_page_delete(struct page *page) > { > - __ClearPageBalloon(page); > + __ClearPageOffline(page); > __ClearPageMovable(page); > set_page_private(page, 0); > /* > @@ -141,13 +141,13 @@ static inline gfp_t balloon_mapping_gfp_mask(void) > static inline void balloon_page_insert(struct balloon_dev_info *balloon, > struct page *page) > { > - __SetPageBalloon(page); > + __SetPageOffline(page); > list_add(&page->lru, &balloon->pages); > } > > static inline void balloon_page_delete(struct page *page) > { > - __ClearPageBalloon(page); > + __ClearPageOffline(page); > list_del(&page->lru); > } > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 50ce1bddaf56..f91da3d0a67e 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -670,7 +670,7 @@ PAGEFLAG_FALSE(DoubleMap) > #define PAGE_TYPE_BASE 0xf0000000 > /* Reserve 0x0000007f to catch underflows of page_mapcount */ > #define PG_buddy 0x00000080 > -#define PG_balloon 0x00000100 > +#define PG_offline 0x00000100 > #define PG_kmemcg 0x00000200 > #define PG_table 0x00000400 > > @@ -700,10 +700,13 @@ static __always_inline void __ClearPage##uname(struct page *page) \ > PAGE_TYPE_OPS(Buddy, buddy) > > /* > - * PageBalloon() is true for pages that are on the balloon page list > - * (see mm/balloon_compaction.c). > + * PageOffline() indicates that the pages is logically offline although the with this typo fixed .. > + * containing section is online. (e.g. inflated in a balloon driver or > + * not onlined when onlining the section). > + * The content of these pages is effectively stale. Such pages should not > + * be touched (read/write/dump/save) except by their owner. > */ > -PAGE_TYPE_OPS(Balloon, balloon) > +PAGE_TYPE_OPS(Offline, offline) > > /* > * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on > diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h > index 21b9113c69da..6f2f2720f3ac 100644 > --- a/include/uapi/linux/kernel-page-flags.h > +++ b/include/uapi/linux/kernel-page-flags.h > @@ -32,7 +32,7 @@ > > #define KPF_KSM 21 > #define KPF_THP 22 > -#define KPF_BALLOON 23 > +#define KPF_OFFLINE 23 > #define KPF_ZERO_PAGE 24 > #define KPF_IDLE 25 > #define KPF_PGTABLE 26 > diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c > index 37908a83ddc2..6c38d3b862e4 100644 > --- a/tools/vm/page-types.c > +++ b/tools/vm/page-types.c > @@ -133,7 +133,7 @@ static const char * const page_flag_names[] = { > [KPF_NOPAGE] = "n:nopage", > [KPF_KSM] = "x:ksm", > [KPF_THP] = "t:thp", > - [KPF_BALLOON] = "o:balloon", > + [KPF_OFFLINE] = "o:offline", > [KPF_PGTABLE] = "g:pgtable", > [KPF_ZERO_PAGE] = "z:zero_page", > [KPF_IDLE] = "i:idle_page", for balloon changes: Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > -- > 2.17.2 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel