On Tue, 2011-05-03 at 08:38 +0200, Johannes Weiner wrote: > On Mon, May 02, 2011 at 06:58:18PM -0500, James Bottomley wrote: > > On Mon, 2011-05-02 at 16:14 -0700, Ying Han wrote: > > > On Mon, May 2, 2011 at 3:48 PM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > > > I am very much for removing this hack. There is still more scan > > > > pressure applied to memcgs in excess of their soft limit even if the > > > > extra scan is happening at a sane priority level. And the fact that > > > > global reclaim operates completely unaware of memcgs is a different > > > > story. > > > > > > > > However, this code came into place with v2.6.31-8387-g4e41695. Why is > > > > it only now showing up? > > > > > > > > You also wrote in that thread that this happens on a standard F15 > > > > installation. On the F15 I am running here, systemd does not > > > > configure memcgs, however. Did you manually configure memcgs and set > > > > soft limits? Because I wonder how it ended up in soft limit reclaim > > > > in the first place. > > > > It doesn't ... it's standard FC15 ... the mere fact of having memcg > > compiled into the kernel is enough to do it (conversely disabling it at > > compile time fixes the problem). > > Does this mean you have not set one up yourself, or does it mean that > you have checked no other software is setting up a soft-limited memcg? Right, I've done nothing other than install and boot. As far as I can tell from /sys/fs/cgroup/memory, nothing is defined other than the standard limits. > Right now, I still don't see how we could enter the problematic path > without one memcg exceeding its soft limit. Yes, that's what we all think too. The limit is way above my memory size, though. > So if you have not done this yet, can you check the cgroup fs for > memcgs, their memory.soft_limit_in_bytes and .usage_in_bytes right > before you would run the workload that reproduces the problem? Sure ... I've got the entire contents at the bottom. > > > curious as well. if we have workload to reproduce it, i would like to try > > > > Well, the only one I can suggest is the one that produces it (large > > untar). There seems to be something magical about the memory size (mine > > is 2G) because adding more also seems to make the problem go away. > > I'll try to reproduce this on my F15 as well. It's an SMP kernel (The core i5 Lenovo laptop has two cores with two threads). Turning on PREEMPT makes the hang go away, but still causes kswapd to loop. James --- ]# for f in *; do echo -e "$f\t"; cat $f;done cgroup.clone_children 0 cgroup.event_control cat: cgroup.event_control: Invalid argument cgroup.procs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 49 50 51 52 53 54 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 335 339 352 370 371 408 409 415 427 431 443 613 614 679 690 704 732 758 759 775 799 800 825 840 849 851 865 866 890 948 964 997 1000 1037 memory.failcnt 0 memory.force_empty cat: memory.force_empty: Invalid argument memory.limit_in_bytes 9223372036854775807 memory.max_usage_in_bytes 0 memory.move_charge_at_immigrate 0 memory.oom_control oom_kill_disable 0 under_oom 0 memory.soft_limit_in_bytes 9223372036854775807 memory.stat cache 68370432 rss 34246656 mapped_file 6008832 pgpgin 132627 pgpgout 107574 inactive_anon 6766592 active_anon 34226176 inactive_file 45350912 active_file 16228352 unevictable 0 hierarchical_memory_limit 9223372036854775807 total_cache 68370432 total_rss 34246656 total_mapped_file 6008832 total_pgpgin 132627 total_pgpgout 107574 total_inactive_anon 6766592 total_active_anon 34226176 total_inactive_file 45350912 total_active_file 16228352 total_unevictable 0 memory.swappiness 60 memory.usage_in_bytes 102617088 memory.use_hierarchy 0 notify_on_release 0 release_agent tasks 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 49 50 51 52 53 54 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 335 339 352 370 371 408 409 415 427 431 443 613 614 679 690 704 732 758 759 775 799 800 825 840 849 851 865 866 890 891 948 964 997 1000 1051 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
