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| author | Rafael Aquini <aquini@redhat.com> | 2012-12-11 16:02:38 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-11 17:22:26 -0800 |
| commit | 18468d93e53b037e1a04ec58398eab763d054064 (patch) | |
| tree | 74392b876400391567f55bb5292107b65e3791a2 /mm/Kconfig | |
| parent | 252aa6f5be64c90c67b9f066ccff880f6b487d32 (diff) | |
| download | lwn-18468d93e53b037e1a04ec58398eab763d054064.tar.gz lwn-18468d93e53b037e1a04ec58398eab763d054064.zip | |
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 <aquini@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/Kconfig')
| -rw-r--r-- | mm/Kconfig | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index a3f8dddaaab3..e6651c5de14f 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -188,6 +188,21 @@ config SPLIT_PTLOCK_CPUS default "4" # +# support for memory balloon compaction +config BALLOON_COMPACTION + bool "Allow for balloon memory compaction/migration" + def_bool y + depends on COMPACTION && VIRTIO_BALLOON + help + 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. Allowing the compaction & migration for memory + pages enlisted as being part of memory balloon devices avoids the + scenario aforementioned and helps improving memory defragmentation. + +# # support for memory compaction config COMPACTION bool "Allow for memory compaction" |