From 18468d93e53b037e1a04ec58398eab763d054064 Mon Sep 17 00:00:00 2001 From: Rafael Aquini Date: Tue, 11 Dec 2012 16:02:38 -0800 Subject: mm: introduce a common interface for balloon pages mobility Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be used within a guest, thus imposing performance penalties associated with the reduced number of transparent huge pages that could be used by the guest workload. This patch introduces a common interface to help a balloon driver on making its page set movable to compaction, and thus allowing the system to better leverage the compation efforts on memory defragmentation. [akpm@linux-foundation.org: use PAGE_FLAGS_CHECK_AT_PREP, s/__balloon_page_flags/page_flags_cleared/, small cleanups] [rientjes@google.com: allow balloon compaction for any system with memory compaction enabled, which is the defconfig] Signed-off-by: Rafael Aquini Acked-by: Mel Gorman Cc: Rusty Russell Cc: "Michael S. Tsirkin" Cc: Rik van Riel Cc: Andi Kleen Cc: Konrad Rzeszutek Wilk Cc: Minchan Kim Signed-off-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pagemap.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux/pagemap.h') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index e42c762f0dc7..6da609d14c15 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -24,6 +24,7 @@ enum mapping_flags { AS_ENOSPC = __GFP_BITS_SHIFT + 1, /* ENOSPC on async write */ AS_MM_ALL_LOCKS = __GFP_BITS_SHIFT + 2, /* under mm_take_all_locks() */ AS_UNEVICTABLE = __GFP_BITS_SHIFT + 3, /* e.g., ramdisk, SHM_LOCK */ + AS_BALLOON_MAP = __GFP_BITS_SHIFT + 4, /* balloon page special map */ }; static inline void mapping_set_error(struct address_space *mapping, int error) @@ -53,6 +54,21 @@ static inline int mapping_unevictable(struct address_space *mapping) return !!mapping; } +static inline void mapping_set_balloon(struct address_space *mapping) +{ + set_bit(AS_BALLOON_MAP, &mapping->flags); +} + +static inline void mapping_clear_balloon(struct address_space *mapping) +{ + clear_bit(AS_BALLOON_MAP, &mapping->flags); +} + +static inline int mapping_balloon(struct address_space *mapping) +{ + return mapping && test_bit(AS_BALLOON_MAP, &mapping->flags); +} + static inline gfp_t mapping_gfp_mask(struct address_space * mapping) { return (__force gfp_t)mapping->flags & __GFP_BITS_MASK; -- cgit v1.2.2