On Thu, May 10, 2012 at 06:38:43PM -0300, Andre Nathan wrote: > Hello > > I'm doing some tests with LXC and how it interacts with the memory > cgroup limits, more specifically the memory.limit_in_bytes control file. > > Am I correct in my understanding of the memory cgroup documentation[1] > that the limit set in memory.limit_in_bytes is applied to the sum of the > fields 'cache', 'rss' and 'mapped_file' in the memory.stat file? mapped_file is the subset of cache that is mapped into virtual memory. cache (= inactive_file + active_file) + rss (= inactive_anon + active_anon) is what the limit applies to. > I am also trying to understand the values reported in memory.stat when > compared to the statistics in /proc/$PID/statm. > > Below is the sum of each field in /proc/$PID/statm for every process > running inside a test container, converted to bytes: > > size resident share text lib data dt > 897208320 28741632 20500480 1171456 0 170676224 0 statms accounts based on virtual memory, not physical memory like memcg does. If you have the same page mapped into two tasks, both their "share" counters will show a page, while the memcg will only account the single physical page in mapped_file. > Compare this with the usage reports from memory.stat (fields total_*, > hierarchical_* and pg* omitted): > > cache 16834560 > rss 8192000 > mapped_file 3743744 > swap 0 > inactive_anon 0 > active_anon 8192000 > inactive_file 13996032 > active_file 2838528 > unevictable 0 > > Is there a way to reconcile these numbers somehow? I understand that the > fields from the two files represent different things. What I'm trying to > do is to combine, for example, the fields from memory.stat to > approximately reach what is displayed by statm. Excluding the memory shared between tasks in the same group from the "shared" counter gets you to "mapped_file" etc. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
