Messages in this thread | | | Date | Thu, 13 Nov 2008 10:27:55 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH 1/6] memcg: free all at rmdir |
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On Thu, 13 Nov 2008 06:50:40 +0530 Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> 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. > No, just for shrinking usage. It can also drops ANON.
> > 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. > account_move did that....
That was only for debug and is a hole for security of resource management. So, removed.
Thanks, -Kame
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