This patch set provides the ability for each cgroup to have independent dirty
page limits.
Limiting dirty memory is like fixing the max amount of dirty (hard to reclaim)
page cache used by a cgroup. So, in case of multiple cgroup writers, they will
not be able to consume more than their designated share of dirty pages and will
be forced to perform write-out if they cross that limit.
These patches were developed and tested on mmotm 2010-09-28-16-13. The patches
are based on a series proposed by Andrea Righi in Mar 2010.
Overview:
- Add page_cgroup flags to record when pages are dirty, in writeback, or nfs
unstable.
- Extend mem_cgroup to record the total number of pages in each of the
interesting dirty states (dirty, writeback, unstable_nfs).
- Add dirty parameters similar to the system-wide /proc/sys/vm/dirty_*
limits to mem_cgroup. The mem_cgroup dirty parameters are accessible
via cgroupfs control files.
- Consider both system and per-memcg dirty limits in page writeback when
deciding to queue background writeback or block for foreground writeback.
Known shortcomings:
- When a cgroup dirty limit is exceeded, then bdi writeback is employed to
writeback dirty inodes. Bdi writeback considers inodes from any cgroup, not
just inodes contributing dirty pages to the cgroup exceeding its limit.
Performance measurements:
- kernel builds are unaffected unless run with a small dirty limit.
- all data collected with CONFIG_CGROUP_MEM_RES_CTLR=y.
- dd has three data points (in secs) for three data sizes (100M, 200M, and 1G).
As expected, dd slows when it exceed its cgroup dirty limit.
kernel_build dd
mmotm 2:37 0.18, 0.38, 1.65
root_memcg
mmotm 2:37 0.18, 0.35, 1.66
non-root_memcg
mmotm+patches 2:37 0.18, 0.35, 1.68
root_memcg
mmotm+patches 2:37 0.19, 0.35, 1.69
non-root_memcg
mmotm+patches 2:37 0.19, 2.34, 22.82
non-root_memcg
150 MiB memcg dirty limit
mmotm+patches 3:58 1.71, 3.38, 17.33
non-root_memcg
1 MiB memcg dirty limit
Greg Thelen (10):
memcg: add page_cgroup flags for dirty page tracking
memcg: document cgroup dirty memory interfaces
memcg: create extensible page stat update routines
memcg: disable local interrupts in lock_page_cgroup()
memcg: add dirty page accounting infrastructure
memcg: add kernel calls for memcg dirty page stats
memcg: add dirty limits to mem_cgroup
memcg: add cgroupfs interface to memcg dirty limits
writeback: make determine_dirtyable_memory() static.
memcg: check memcg dirty limits in page writeback
Documentation/cgroups/memory.txt | 37 ++++
fs/nfs/write.c | 4 +
include/linux/memcontrol.h | 78 +++++++-
include/linux/page_cgroup.h | 31 +++-
include/linux/writeback.h | 2 -
mm/filemap.c | 1 +
mm/memcontrol.c | 426 ++++++++++++++++++++++++++++++++++----
mm/page-writeback.c | 211 ++++++++++++-------
mm/rmap.c | 4 +-
mm/truncate.c | 1 +
10 files changed, 672 insertions(+), 123 deletions(-)
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>