Messages in this thread | | | Date | Tue, 1 Jun 2010 18:20:25 +0200 | From | Andi Kleen <> | Subject | Re: [rfc] forked kernel task and mm structures imbalanced on NUMA |
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On Wed, Jun 02, 2010 at 01:59:43AM +1000, Nick Piggin wrote: > On Tue, Jun 01, 2010 at 05:48:10PM +0200, Andi Kleen wrote: > > Nick Piggin <npiggin@suse.de> writes: > > > > > This isn't really a new problem, and I don't know how important it is, > > > but I recently came across it again when doing some aim7 testing with > > > huge numbers of tasks. > > > > Seems reasonable. Of course you need to at least > > save/restore the old CPU policy, and use a subset of it. > > The mpolicy? My patch does that (mpol_prefer_cpu_start/end). The real > problem is that it can actually violate the parent's mempolicy. For > example MPOL_BIND and cpus_allowed set on a node outside the mempolicy.
I don't see where you store 'old', but maybe I missed it.
> > slightly more difficult. The advantage would be that on multiple > > migrations it would follow. And it would be a bit slower for > > the initial case. > > Migrate what on touch? Talking mainly about kernel memory structures, > task_struct, mm, vmas, page tables, kernel stack, etc.
Migrate task_struct, mm, vmas, page tables, kernel stack on reasonable touch. As long as they are not shared it shouldn't be too difficult.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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