Messages in this thread | | | Subject | Re: [PATCH 0/5] make slab gfp fair | From | Peter Zijlstra <> | Date | Mon, 14 May 2007 19:40:52 +0200 |
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On Mon, 2007-05-14 at 09:29 -0700, Christoph Lameter wrote: > On Mon, 14 May 2007, Matt Mackall wrote: > > > privileged thread unprivileged greedy process > > kmem_cache_alloc(...) > > adds new slab page from lowmem pool > > Yes but it returns an object for the privileged thread. Is that not > enough?
No, because we reserved memory for n objects, and like matt illustrates most of those that will be eaten by the greedy process.
We could reserve 1 page per object but that rather bloats the reserve.
> > do_io() > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > ... > > eats it all > > kmem_cache_alloc(...) -> ENOMEM > > who ate my donuts?! > > > > But I think this solution is somehow overkill. If we only care about > > this issue in the OOM avoidance case, then our rank reduces to a > > boolean.
I tried to slim it down to a two state affair; but last time I tried performance runs that actually slowed it down some.
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