Re: memcg: Fix init/Kconfig documentation
From: Balbir Singh
Date: Tue Oct 21 2008 - 02:18:21 EST
KAMEZAWA Hiroyuki wrote:
> On Tue, 21 Oct 2008 11:21:18 +0530
> Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>> From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
>> Date: Tue, 21 Oct 2008 11:12:45 +0530
>> Subject: [PATCH] memcg: Update Kconfig to remove the struct page overhead statement.
>> The memory resource controller no longer has a struct page overhead
>> associated with it. The init/Kconfig help has been replaced with
>> something more suitable based on the current implementation.
> Oh, this is my version..could you merge if this includes something good ?
> Fixes menu help text for memcg-allocate-page-cgroup-at-boot.patch.
> Signed-off-by: KAMEZAWA hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> init/Kconfig | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
> Index: mmotm-2.6.27+/init/Kconfig
> --- mmotm-2.6.27+.orig/init/Kconfig
> +++ mmotm-2.6.27+/init/Kconfig
> @@ -401,16 +401,20 @@ config CGROUP_MEM_RES_CTLR
> depends on CGROUPS && RESOURCE_COUNTERS
> select MM_OWNER
> - Provides a memory resource controller that manages both page cache and
> - RSS memory.
> + Provides a memory resource controller that manages both anonymous
> + memory and page cache. (See Documentation/controllers/memory.txt)
> Note that setting this option increases fixed memory overhead
> - associated with each page of memory in the system by 4/8 bytes
> - and also increases cache misses because struct page on many 64bit
> - systems will not fit into a single cache line anymore.
> + associated with each page of memory in the system. By this,
> + 20(40)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory
> + usage tracking struct at boot. Total amount of this is printed out
> + at boot.
> Only enable when you're ok with these trade offs and really
> - sure you need the memory resource controller.
> + sure you need the memory resource controller. Even when you enable
> + this, you can set "cgroup_disable=memory" at your boot option to
> + disable memory resource controller and you can avoid almost all bads.
> + (and lost benefits of memory resource contoller)
> This config option also selects MM_OWNER config option, which
> could in turn add some fork/exit overhead.
Looks good otherwise.
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