On Wed, Feb 27 2013, Roman Gushchin wrote: > Hi, all! > > I've implemented low limits for memory cgroups. The primary goal was to add > an ability > to protect some memory from reclaiming without using mlock(). A kind of "soft > mlock()". > > I think this patch will be helpful when it's necessary to protect production > processes from > memory-wasting backup processes. > > -- > > Low limits for memory cgroup can be used to limit memory pressure on it. > If memory usage of a cgroup is under it's low limit, it will not be > affected by global reclaim. If it reaches it's low limit from above, > the reclaiming speed will be dropped exponentially. > > Low limits don't affect soft reclaim. > Also, it's possible that a cgroup with memory usage under low limit > will be reclaimed slowly on very low scanning priorities.
So the new low limit is not a rigid limit. Global reclaim can reclaim from a cgroup when its usage is below low_limit_in_bytes although such reclaim is less aggressive than when usage is above low_limit_in_bytes. Correct? Why doesn't memcg reclaim (i.e. !global_reclaim) also consider low_limit_in_bytes? Do you have demonstration of how this improves system operation? Why is soft_limit insufficient? > Signed-off-by: Roman Gushchin <kl...@yandex-team.ru> > --- > include/linux/memcontrol.h | 7 +++++ > include/linux/res_counter.h | 17 +++++++++++ > kernel/res_counter.c | 2 ++ > mm/memcontrol.c | 67 > +++++++++++++++++++++++++++++++++++++++++++ > mm/vmscan.c | 5 ++++ > 5 files changed, 98 insertions(+) Need to update Documentation/cgroups/memory.txt explaining the external behavior of this new know and how it interacts with soft_limit_in_bytes. -- 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/
