On Sat, Aug 25, 2012 at 02:24:55AM -0300, Rafael Aquini wrote: > 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 Meta-question: are there any numbers showing gain from this patchset? The reason I ask, on migration we notify host about each page individually. If this is rare maybe the patchset does not help much. If this is common we would be better off building up a list of multiple pages and passing them in one go. > 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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