Messages in this thread | | | Date | Thu, 13 Nov 2008 06:50:40 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][PATCH 1/6] memcg: free all at rmdir |
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KAMEZAWA Hiroyuki wrote: > On Wed, 12 Nov 2008 16:07:58 -0800 > Andrew Morton <akpm@linux-foundation.org> wrote: > >> 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? >> > In my plan, I'll add > > memory.shrink_usage interface to do and allows > > #echo 0M > memory.shrink_memory_usage > (you may swap tasks out if there is task..) > > to drop pages. >
So, shrink_memory_usage is just for dropping caches? I don't understand the part about swap tasks out.
> Balbir, how do you think ? I've already removed "force_empty".
Have you? Won't that go against API/ABI compatibility guidelines. I would recommend cc'ing linux-api as well. Sorry, I missed the patch that removes force_empty. Me culpa.
-- Balbir
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