Messages in this thread | | | Date | Wed, 12 Nov 2008 16:07:58 -0800 | From | Andrew Morton <> | Subject | Re: [RFC][PATCH 1/6] memcg: free all at rmdir |
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On Wed, 12 Nov 2008 12:26:56 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> +5.1 on_rmdir > +set behavior of memcg at rmdir (Removing cgroup) default is "drop". > + > +5.1.1 drop > + #echo on_rmdir drop > memory.attribute > + This is default. All pages on the memcg will be freed. > + If pages are locked or too busy, they will be moved up to the parent. > + Useful when you want to drop (large) page caches used in this memcg. > + But some of in-use page cache can be dropped by this. > + > +5.1.2 keep > + #echo on_rmdir keep > memory.attribute > + All pages on the memcg will be moved to its parent. > + Useful when you don't want to drop page caches used in this memcg. > + You can keep page caches from some library or DB accessed by this > + memcg on memory.
Would it not be more useful to implement a per-memcg version of /proc/sys/vm/drop_caches? (One without drop_caches' locking bug, hopefully).
If we do this then we can make the above "keep" behaviour non-optional, and the operator gets to choose whether or not to drop the caches before doing the rmdir.
Plus, we get a new per-memcg drop_caches capability. And it's a nicer interface, and it doesn't have the obvious races which on_rmdir has, etc.
hm?
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