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-set follows the main idea discussed at 2012 LSFMMS session: "Ballooning for transparent huge pages" -- http://lwn.net/Articles/490114/ to introduce the required changes to the virtio_balloon driver, as well as the changes to the core compaction & migration bits, in order to make those subsystems aware of ballooned pages and allow memory balloon pages become movable within a guest, thus avoiding the aforementioned fragmentation issue Rafael Aquini (4): mm: introduce compaction and migration for virtio ballooned pages virtio_balloon: introduce migration primitives to balloon pages mm: introduce putback_movable_pages() mm: add vm event counters for balloon pages compaction drivers/virtio/virtio_balloon.c | 139 +++++++++++++++++++++++++++++++++++++--- include/linux/migrate.h | 2 + include/linux/mm.h | 17 +++++ include/linux/virtio_balloon.h | 4 ++ include/linux/vm_event_item.h | 8 ++- mm/compaction.c | 131 +++++++++++++++++++++++++++++++------ mm/migrate.c | 51 ++++++++++++++- mm/page_alloc.c | 2 +- mm/vmstat.c | 10 ++- 9 files changed, 331 insertions(+), 33 deletions(-) Change log: v7: * fix a potential page leak case at 'putback_balloon_page' (Mel); * adjust vm-events-counter patch and remove its drop-on-merge message (Rik); * add 'putback_movable_pages' to avoid hacks on 'putback_lru_pages' (Minchan); v6: * rename 'is_balloon_page()' to 'movable_balloon_page()' (Rik); v5: * address Andrew Morton's review comments on the patch series; * address a couple extra nitpick suggestions on PATCH 01 (Minchan); v4: * address Rusty Russel's review comments on PATCH 02; * re-base virtio_balloon patch on 9c378abc5c0c6fc8e3acf5968924d274503819b3; V3: * address reviewers nitpick suggestions on PATCH 01 (Mel, Minchan); V2: * address Mel Gorman's review comments on PATCH 01; Preliminary test results: (2 VCPU 2048mB RAM KVM guest running 3.6.0_rc1+ -- after a reboot) * 64mB balloon: [root@localhost ~]# awk '/compact/ {print}' /proc/vmstat compact_blocks_moved 0 compact_pages_moved 0 compact_pagemigrate_failed 0 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_isolated 0 compact_balloon_migrated 0 compact_balloon_returned 0 compact_balloon_released 0 [root@localhost ~]# [root@localhost ~]# for i in $(seq 1 6); do echo 1 > /proc/sys/vm/compact_memory & done &>/dev/null [1] Done echo 1 > /proc/sys/vm/compact_memory [2] Done echo 1 > /proc/sys/vm/compact_memory [3] Done echo 1 > /proc/sys/vm/compact_memory [4] Done echo 1 > /proc/sys/vm/compact_memory [5]- Done echo 1 > /proc/sys/vm/compact_memory [6]+ Done echo 1 > /proc/sys/vm/compact_memory [root@localhost ~]# [root@localhost ~]# awk '/compact/ {print}' /proc/vmstat compact_blocks_moved 6579 compact_pages_moved 50114 compact_pagemigrate_failed 111 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_isolated 18361 compact_balloon_migrated 18306 compact_balloon_returned 55 compact_balloon_released 18306 * 128 mB balloon: [root@localhost ~]# awk '/compact/ {print}' /proc/vmstat compact_blocks_moved 0 compact_pages_moved 0 compact_pagemigrate_failed 0 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_isolated 0 compact_balloon_migrated 0 compact_balloon_returned 0 compact_balloon_released 0 [root@localhost ~]# [root@localhost ~]# for i in $(seq 1 6); do echo 1 > /proc/sys/vm/compact_memory & done &>/dev/null [1] Done echo 1 > /proc/sys/vm/compact_memory [2] Done echo 1 > /proc/sys/vm/compact_memory [3] Done echo 1 > /proc/sys/vm/compact_memory [4] Done echo 1 > /proc/sys/vm/compact_memory [5]- Done echo 1 > /proc/sys/vm/compact_memory [6]+ Done echo 1 > /proc/sys/vm/compact_memory [root@localhost ~]# [root@localhost ~]# awk '/compact/ {print}' /proc/vmstat compact_blocks_moved 6789 compact_pages_moved 64479 compact_pagemigrate_failed 127 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_isolated 33937 compact_balloon_migrated 33869 compact_balloon_returned 68 compact_balloon_released 33869 -- 1.7.11.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>