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 (5): mm: introduce a common interface for balloon pages mobility mm: introduce compaction and migration for 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 | 287 ++++++++++++++++++++++++++++++++++--- include/linux/balloon_compaction.h | 137 ++++++++++++++++++ include/linux/migrate.h | 2 + include/linux/pagemap.h | 18 +++ include/linux/vm_event_item.h | 8 +- mm/Kconfig | 15 ++ mm/Makefile | 2 +- mm/balloon_compaction.c | 174 ++++++++++++++++++++++ mm/compaction.c | 51 ++++--- mm/migrate.c | 57 +++++++- mm/page_alloc.c | 2 +- mm/vmstat.c | 10 +- 12 files changed, 715 insertions(+), 48 deletions(-) create mode 100644 include/linux/balloon_compaction.h create mode 100644 mm/balloon_compaction.c Change log: v9: * Adjust rcu_dereference usage to leverage page lock protection (Paul, Peter); * Enhance doc on compaction interface introduced to balloon driver (Michael); * Fix issue with isolated pages breaking leak_balloon() logics (Michael); v8: * introduce a common MM interface for balloon driver page compaction (Michael); * remove the global state preventing multiple balloon device support (Michael); * introduce RCU protection/syncrhonization to balloon page->mapping (Michael); 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_rc3+ -- 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_released 0 compact_balloon_returned 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 3108 compact_pages_moved 43169 compact_pagemigrate_failed 95 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_isolated 16384 compact_balloon_migrated 16384 compact_balloon_released 16384 compact_balloon_returned 0 * 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_released 0 compact_balloon_returned 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 3062 compact_pages_moved 49774 compact_pagemigrate_failed 129 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_isolated 26076 compact_balloon_migrated 25957 compact_balloon_released 25957 compact_balloon_returned 119 -- 1.7.11.4 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
