* Greg Thelen <gthelen@xxxxxxxxxx> [2010-10-03 23:57:55]: > 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, could you please try the parallel page fault test. Could you look at commit 0c3e73e84fe3f64cf1c2e8bb4e91e8901cbcdc38 and 569b846df54ffb2827b83ce3244c5f032394cba4 for examples. -- Three Cheers, Balbir -- 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>