Home » Mailing lists » Devel » [PATCH v6 00/10] Request for inclusion: per-cgroup tcp memory pressure controls
| Re: [PATCH v6 01/10] Basic kernel memory functionality for the Memory Controller [message #44245 is a reply to message #44228] |
Mon, 28 November 2011 02:24   |
KAMEZAWA Hiroyuki
Messages: 463
Registered: September 2006
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Senior Member |
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On Fri, 25 Nov 2011 15:38:07 -0200
Glauber Costa <glommer@parallels.com> wrote:
> This patch lays down the foundation for the kernel memory component
> of the Memory Controller.
>
> As of today, I am only laying down the following files:
>
> * memory.independent_kmem_limit
> * memory.kmem.limit_in_bytes (currently ignored)
> * memory.kmem.usage_in_bytes (always zero)
>
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
> CC: Paul Menage <paul@paulmenage.org>
> CC: Greg Thelen <gthelen@google.com>
> ---
> Documentation/cgroups/memory.txt | 36 ++++++++++++-
> init/Kconfig | 14 +++++
> mm/memcontrol.c | 107 ++++++++++++++++++++++++++++++++++++--
> 3 files changed, 150 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index 06eb6d9..bf00cd2 100644
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -44,8 +44,9 @@ Features:
> - oom-killer disable knob and oom-notifier
> - Root cgroup has no limit controls.
>
> - Kernel memory and Hugepages are not under control yet. We just manage
> - pages on LRU. To add more controls, we have to take care of performance.
> + Hugepages is not under control yet. We just manage pages on LRU. To add more
> + controls, we have to take care of performance. Kernel memory support is work
> + in progress, and the current version provides basically functionality.
>
> Brief summary of control files.
>
> @@ -56,8 +57,11 @@ Brief summary of control files.
> (See 5.5 for details)
> memory.memsw.usage_in_bytes # show current res_counter usage for memory+Swap
> (See 5.5 for details)
> + memory.kmem.usage_in_bytes # show current res_counter usage for kmem only.
> + (See 2.7 for details)
> memory.limit_in_bytes # set/show limit of memory usage
> memory.memsw.limit_in_bytes # set/show limit of memory+Swap usage
> + memory.kmem.limit_in_bytes # if allowed, set/show limit of kernel memory
> memory.failcnt # show the number of memory usage hits limits
> memory.memsw.failcnt # show the number of memory+Swap hits limits
> memory.max_usage_in_bytes # show max memory usage recorded
> @@ -72,6 +76,9 @@ Brief summary of control files.
> memory.oom_control # set/show oom controls.
> memory.numa_stat # show the number of memory usage per numa node
>
> + memory.independent_kmem_limit # select whether or not kernel memory limits are
> + independent of user limits
> +
> 1. History
>
> The memory controller has a long history. A request for comments for the memory
> @@ -255,6 +262,31 @@ When oom event notifier is registered, event will be delivered.
> per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
> zone->lru_lock, it has no lock of its own.
>
> +2.7 Kernel Memory Extension (CONFIG_CGROUP_MEM_RES_CTLR_KMEM)
> +
> + With the Kernel memory extension, the Memory Controller is able to limit
> +the amount of kernel memory used by the system. Kernel memory is fundamentally
> +different than user memory, since it can't be swapped out, which makes it
> +possible to DoS the system by consuming too much of this precious resource.
> +Kernel memory limits are not imposed for the root cgroup.
> +
> +Memory limits as specified by the standard Memory Controller may or may not
> +take kernel memory into consideration. This is achieved through the file
> +memory.independent_kmem_limit. A Value different than 0 will allow for kernel
> +memory to be controlled separately.
> +
> +When kernel memory limits are not independent, the limit values set in
> +memory.kmem files are ignored.
> +
> +Currently no soft limit is implemented for kernel memory. It is future work
> +to trigger slab reclaim when those limits are reached.
> +
> +CAUTION: As of this writing, the kmem extention may prevent tasks from moving
> +among cgroups. If a task has kmem accounting in a cgroup, the task cannot be
> +moved until the kmem resource is released. Also, until the resource is fully
> +released, the cgroup cannot be destroyed. So, please consider your use cases
> +and set kmem extention config option carefully.
> +
This seems that memcg 'has' kernel memory limiting feature for all kinds of kmem..
Could you add a list of "currently controled kmems" section ?
And update the list in later patch ?
Thanks,
-Kame
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