[Devel] Re: [lxc-devel] Memory Resources
Krzysztof Taraszka
krzysztof.taraszka at gnuhosting.net
Sun Aug 23 14:12:24 PDT 2009
:) excelent :)
my ugly patch printing right now undefinied data but the idea was the same
:)
how about memsw_limit for swap? :>
I am looking for swap usage statistics from cgroup right now from
memcontrol.c :) but as you did the idea is good and should be add to the
kernel and lxc-tools :)
2009/8/23 Daniel Lezcano <daniel.lezcano at free.fr>
> Krzysztof Taraszka wrote:
>
>> 2009/8/23 Daniel Lezcano <daniel.lezcano at free.fr>
>>
>> Krzysztof Taraszka wrote:
>>>
>>> 2009/8/23 Krzysztof Taraszka <krzysztof.taraszka at gnuhosting.net>
>>>>
>>>>
>>>>
>>>> 2009/8/23 Krzysztof Taraszka <krzysztof.taraszka at gnuhosting.net>
>>>>>
>>>>>
>>>>>
>>>>> 2009/8/23 Daniel Lezcano <daniel.lezcano at free.fr>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Krzysztof Taraszka wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> 2009/8/23 Daniel Lezcano <daniel.lezcano at free.fr>
>>>>>>>>
>>>>>>>> Krzysztof Taraszka wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I am running lxc on my debian unstable sandbox and I have a few
>>>>>>>>>> question
>>>>>>>>>> about memory managament inside linux containers based on lxc
>>>>>>>>>> project.
>>>>>>>>>>
>>>>>>>>>> I have got linux kernel 2.6.30.5 with enabled :
>>>>>>>>>>
>>>>>>>>>> +Resource counter
>>>>>>>>>> ++ Memory Resource Controller for Control Groups
>>>>>>>>>> +++ Memory Resource Controller Swap Extension(EXPERIMENTAL)
>>>>>>>>>>
>>>>>>>>>> lxc-checkconfig pass all checks.
>>>>>>>>>>
>>>>>>>>>> I read about cgroups memory managament
>>>>>>>>>> (Documentation/cgroups/memory.txt)
>>>>>>>>>> and I tried to pass those value to my debian sandbox.
>>>>>>>>>>
>>>>>>>>>> And...
>>>>>>>>>> 'free -m' and 'top/htop' still show all available memory inside
>>>>>>>>>> container
>>>>>>>>>> (also If I set 32M for lxc.cgroup.memory.limit_in_bytes and
>>>>>>>>>> lxc.cgroup.memory.usage_in_bytes; and 64M for
>>>>>>>>>> lxc.cgroup.memory.memsw.usage_in_bytes and
>>>>>>>>>> lxc.cgroup.memory.memsw.limit_in_bytes free and top show all
>>>>>>>>>> resources).
>>>>>>>>>>
>>>>>>>>>> What I did wrong? Does the container always show all available
>>>>>>>>>> memory
>>>>>>>>>> resources without cgroup limitations?
>>>>>>>>>>
>>>>>>>>>> At the first glance I would say the configuration is correct.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> But AFAIR, the memory cgroup is not isolated, if you specify 32MB
>>>>>>>>> you
>>>>>>>>> will
>>>>>>>>> see all the memory available on the system either if you are not
>>>>>>>>> allowed to
>>>>>>>>> use more than 32MB. If you create a program which allocates 64MB
>>>>>>>>> within
>>>>>>>>> a
>>>>>>>>> container configured with 32MB, and you "touch" the pages (may be
>>>>>>>>> that
>>>>>>>>> can
>>>>>>>>> be done with one mmap call with the MAP_POPULATE option), you
>>>>>>>>> should
>>>>>>>>> see the
>>>>>>>>> application swapping and the "memory.failcnt" increasing.
>>>>>>>>>
>>>>>>>>> IMHO, showing all the memory available for the system instead of
>>>>>>>>> showing
>>>>>>>>> the allowed memory with the cgroup is weird but maybe there is a
>>>>>>>>> good
>>>>>>>>> reason
>>>>>>>>> to do that.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Thank you Daniel for your reply.
>>>>>>>> I think that LXC should isolate memory available for containers like
>>>>>>>> Vserver
>>>>>>>> or FreeVPS do (memory + swap) if .cgroup.memory.* and
>>>>>>>> lxc.cgroup.memory.memsw.* is set.
>>>>>>>> Is there any possibility to make a patch for linux kernel /
>>>>>>>> lxc-tools
>>>>>>>> to
>>>>>>>> show the limitations inside cointainers propertly? I think is a good
>>>>>>>> idea
>>>>>>>> and it should be apply as soon as possible.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Maybe a solution can be to add a new memory.meminfo file in the
>>>>>>> same
>>>>>>> format than /proc/meminfo, so it will be possible to mount --bind
>>>>>>> /cgroup/foo/memory.meminfo to /proc/meminfo for the container.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Yes, I thought the same. This should allow the user-space tools
>>>>>> based on
>>>>>> /proc/meminfo (such as comand line "free") show limited information :)
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hmmm... does the memory.stat is a good start point for make new one
>>>>> object
>>>>> memory.meminfo similar to /proc/meminfo? If so, I can play by my self
>>>>> with
>>>>> lxc-tools code.
>>>>>
>>>>>
>>>>>
>>>>>
>>>> Hmmm... Daniel, I have got a question (that do I thinking in the right
>>>> way).
>>>> here is an output from /proc/meminfo from openvz:
>>>>
>>>>
>>>> MemTotal: 262144 kB
>>>> MemFree: 232560 kB
>>>> Buffers: 0 kB
>>>> Cached: 0 kB
>>>> SwapCached: 0 kB
>>>> Active: 0 kB
>>>> Inactive: 0 kB
>>>> HighTotal: 0 kB
>>>> HighFree: 0 kB
>>>> LowTotal: 262144 kB
>>>> LowFree: 232560 kB
>>>> SwapTotal: 0 kB
>>>> SwapFree: 0 kB
>>>> Dirty: 0 kB
>>>> Writeback: 0 kB
>>>> AnonPages: 0 kB
>>>> Mapped: 0 kB
>>>> Slab: 0 kB
>>>> SReclaimable: 0 kB
>>>> SUnreclaim: 0 kB
>>>> PageTables: 0 kB
>>>> NFS_Unstable: 0 kB
>>>> Bounce: 0 kB
>>>> WritebackTmp: 0 kB
>>>> CommitLimit: 0 kB
>>>> Committed_AS: 0 kB
>>>> VmallocTotal: 0 kB
>>>> VmallocUsed: 0 kB
>>>> VmallocChunk: 0 kB
>>>> HugePages_Total: 0
>>>> HugePages_Free: 0
>>>> HugePages_Rsvd: 0
>>>> HugePages_Surp: 0
>>>> Hugepagesize: 2048 kB
>>>>
>>>> most of values are 0.
>>>>
>>>> I have an question about SwapTotal and SwapFree for LXC.
>>>> As I thinking that:
>>>>
>>>> MemTotal might be: hierarchical_memory_limit
>>>> MemFree might be: hierarchical_memory_limit - cache
>>>>
>>>>
>>>> I am not a memory expert, but isn't MemFree : hierarchical_memory_limit
>>> -
>>> rss ?
>>>
>>> the
>>>>
>>>> SwapTotal might be: hierarchical_memsw_limit
>>>> SwapFree might be: hierarchical_memsw_limit - rss
>>>>
>>>> rss - # of bytes of anonymous and swap cache memory
>>>> I don't know at all that hierarchical_memsw_limit is an good value for
>>>> swap
>>>> total, because as I read it is a mem+swap at all.
>>>>
>>>> Does the lxc memory.meminfo might look like above? Where can I get the
>>>> Hugepagesize?
>>>>
>>>>
>>>> Right, I agree most of the interesting information to create a
>>> memory.meminfo is already there in another file and another format.
>>> Probably
>>> some informations in memory.stat can be moved to memory.meminfo and this
>>> one
>>> can be step by step filled with cgroup memory statistic informations.
>>> IMO,
>>> if the memory controller displays memory statistics like a proc/meminfo
>>> file
>>> format, that will make consistency for these informations and make
>>> trivial
>>> the isolation/virtualization with a simple mount-bind.
>>>
>>>
>>>
>>> Hmm..
>> might be. Right now I am looking for and writing new function in
>> mm/memcontrol.c file for writing some stats in memory.meminfo file for
>> tests.
>> Dirty and ugly part of code, but if it will work as we thought
>> (mount-bind)
>> and as you wrote above, that will be very simple.
>> I am going to look how does the /proc/meminfo is doing by the openvz.
>> mm/memcontrol.c was wrote by xemul from openvz and balbir from ibm.
>> If I am thinking in the right way, guys from openvz made their own patch
>> for
>> meminfo based on the mm/memcontrol.c. If I am wrong - where do they taking
>> meminfo data? :)
>>
>
> I did this ugly patch patch for MemTotal/MemFree - maybe wrong :)
>
> Index: linux-2.6/mm/memcontrol.c
> ===================================================================
> --- linux-2.6.orig/mm/memcontrol.c 2009-06-23 12:00:52.000000000 +0200
> +++ linux-2.6/mm/memcontrol.c 2009-08-23 22:49:02.000000000 +0200
> @@ -2200,6 +2200,27 @@ static int mem_cgroup_swappiness_write(s
> }
>
>
> +static int mem_cgroup_meminfo(struct cgroup *cgrp, struct cftype *cft,
> + struct seq_file *seq)
> +{
> +#define K(x) ((x) << 10)
> +
> + struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cgrp);
> + struct mcs_total_stat mystat = { };
> + unsigned long long limit, memsw_limit;
> +
> + mem_cgroup_get_local_stat(mem_cont, &mystat);
> + memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
> +
> + seq_printf(seq,
> + "MemTotal: %8llu kB\n"
> + "MemFree: %8llu kB\n",
> + limit / 1024, (limit - mystat.stat[MCS_RSS]) / 1024);
> +
> + return 0;
> +#undef K
> +}
> +
> static struct cftype mem_cgroup_files[] = {
> {
> .name = "usage_in_bytes",
> @@ -2242,6 +2263,10 @@ static struct cftype mem_cgroup_files[]
> .read_u64 = mem_cgroup_swappiness_read,
> .write_u64 = mem_cgroup_swappiness_write,
> },
> + {
> + .name = "meminfo",
> + .read_seq_string = mem_cgroup_meminfo,
> + },
> };
>
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
>
>
> With the lxc tools I did:
>
> lxc-execute -n foo /bin/bash
> echo 268435456 > /cgroup/foo/memory.limit_in_bytes
> mount --bind /cgroup/foo/memory.meminfo /proc/meminfo
> for i in $(seq 1 100); do sleep 3600 & done
>
> And the result for "free" is:
>
> free:
>
> total used free shared buffers cached
> Mem: 262144 9692 252452 0 0 0
> -/+ buffers/cache: 9692 252452
> Swap: 0 0 0
>
>
> and for "top":
>
> top - 22:57:37 up 8 min, 1 user, load average: 0.00, 0.02, 0.00
> Tasks: 104 total, 1 running, 103 sleeping, 0 stopped, 0 zombie
> Cpu(s): 0.3%us, 1.0%sy, 0.0%ni, 98.4%id, 0.0%wa, 0.0%hi, 0.3%si,
> 0.0%st
> Mem: 262144k total, 9864k used, 252280k free, 0k buffers
> Swap: 0k total, 0k used, 0k free, 0k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 337 root 20 0 14748 1132 872 R 1.0 0.4 0:00.24 top
> 1 root 20 0 8136 484 408 S 0.0 0.2 0:00.00 lxc-init
> 2 root 20 0 89980 1724 1348 S 0.0 0.7 0:00.70 bash
> 25 root 20 0 86916 612 524 S 0.0 0.2 0:00.00 sleep
> 232 root 20 0 86916 616 524 S 0.0 0.2 0:00.00 sleep
> 233 root 20 0 86916 612 524 S 0.0 0.2 0:00.00 sleep
> 234 root 20 0 86916 612 524 S 0.0 0.2 0:00.00 sleep
> 235 root 20 0 86916 612 524 S 0.0 0.2 0:00.00 sleep
> .....
>
>
> :)
>
>
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