[PATCH v5 0/3] make balloon pages movable by compaction

From: Rafael Aquini
Date: Mon Aug 06 2012 - 09:57:36 EST


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

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