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 (3): mm: introduce compaction and migration for virtio ballooned pages virtio_balloon: introduce migration primitives to balloon pages mm: add vm event counters for balloon pages compaction drivers/virtio/virtio_balloon.c | 139 +++++++++++++++++++++++++++++++++++++--- include/linux/mm.h | 26 ++++++++ include/linux/virtio_balloon.h | 4 ++ include/linux/vm_event_item.h | 2 + mm/compaction.c | 131 +++++++++++++++++++++++++++++++------ mm/migrate.c | 34 +++++++++- mm/vmstat.c | 4 ++ 7 files changed, 312 insertions(+), 28 deletions(-) Change log: 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 1024mB 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_migrated 0 compact_balloon_failed 0 compact_balloon_isolated 0 compact_balloon_freed 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 3520 compact_pages_moved 47548 compact_pagemigrate_failed 120 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_migrated 16378 compact_balloon_failed 0 compact_balloon_isolated 16378 compact_balloon_freed 16378 * 128mB 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_migrated 0 compact_balloon_failed 0 compact_balloon_isolated 0 compact_balloon_freed 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 3356 compact_pages_moved 47099 compact_pagemigrate_failed 158 compact_stall 0 compact_fail 0 compact_success 0 compact_balloon_migrated 26275 compact_balloon_failed 42 compact_balloon_isolated 26317 compact_balloon_freed 26275 -- 1.7.11.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
