Messages in this thread | | | Date | Tue, 4 Nov 2008 14:35:34 -0800 | From | Andrew Morton <> | Subject | Re: [patch 0/7] cpuset writeback throttling |
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On Tue, 4 Nov 2008 16:17:52 -0600 (CST) Christoph Lameter <cl@linux-foundation.org> wrote:
> On Tue, 4 Nov 2008, Andrew Morton wrote: > > > What are the alternatives here? What do we need to do to make > > throttling a per-memcg thing? > > Add statistics to the memcg lru and then you need some kind of sets of > memcgs that are represented by bitmaps or so attached to an inode. > > > The patchset is badly misnamed, btw. It doesn't throttle writeback - > > in fact several people are working on IO bandwidth controllers and > > calling this thing "writeback throttling" risks confusion. > > It is limiting dirty pages and throttling the dirty rate of applications > in a NUMA system (same procedure as we do in non NUMA). The excessive > dirtying without this patchset can cause OOMs to occur on NUMA systems.
yup.
To fix this with a memcg-based throttling, the operator would need to be able to create memcg's which have pages only from particular nodes. (That's a bit indirect relative to what they want to do, but is presumably workable).
But do we even have that capability now?
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