Re: [RFC][PATCH 3/3] memcg documenation soft limit (Yet Another One)
From: Randy Dunlap
Date: Fri Mar 06 2009 - 11:47:08 EST
KAMEZAWA Hiroyuki wrote:
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> Documentation for softlimit (3/3)
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
> Documentation/cgroups/memory.txt | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> Index: mmotm-2.6.29-Mar3/Documentation/cgroups/memory.txt
> ===================================================================
> --- mmotm-2.6.29-Mar3.orig/Documentation/cgroups/memory.txt
> +++ mmotm-2.6.29-Mar3/Documentation/cgroups/memory.txt
> @@ -322,6 +322,25 @@ will be charged as a new owner of it.
> - a cgroup which uses hierarchy and it has child cgroup.
> - a cgroup which uses hierarchy and not the root of hierarchy.
>
> +5.4 softlimit
> + Memory cgroup supports softlimit and has 2 params for control.
parameters
> + - memory.softlimit_in_bytes
> + - softlimit to this cgroup.
softlimit for this cgroup
(i.e., no beginning '-' and no ending '.')
> + - memory.softlimit_priority.
> + - priority of this cgroup at softlimit reclaim.
priority of this cgroup at softlimit reclaim
> + Allowed priority level is 3-0 and 3 is the lowest.
Not very user friendly...
> + If 0, this cgroup will not be target of softlimit.
> +
> + At memory shortage of the system (or local node/zone), softlimit helps
> + kswapd(), a global memory recalim kernel thread, and inform victim cgroup
reclaim informs
> + to be shrinked to kswapd.
> +
> + Victim selection logic:
> + The kernel searches from the lowest priroty(3) up to the highest(1).
priority 0 ?? (from above)
> + If it find a cgroup witch has memory larger than softlimit, steal memory
finds which
> + from it.
> + If multiple cgroups are on the same priority, each cgroup wil be a
will
> + victim in turn.
>
> 6. Hierarchy support
--
~Randy
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