Messages in this thread | | | From | Nick Piggin <> | Subject | Re: [PATCH] SLUB: revert direct page allocator pass through | Date | Sat, 24 Jan 2009 02:12:57 +1100 |
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On Saturday 24 January 2009 02:03:22 Christoph Lameter wrote: > On Fri, 23 Jan 2009, Nick Piggin wrote: > > Hmm, it lists quite a number of advantages that I guess are being > > reverted too? What was the test case(s) that prompted this commit > > in the first place? Better ensure it doesn't slow down... > > The advantage was mainly memory savings and abilty to redefined kmallocs > to go directly to the page allocator. Totally avoids slab allocator > overhead.
Well it sounds in the changelog like a massive performance advantage. Unfortunately it doesn't really say what the workload was.
> I thought higher order allocations were not supposed to be used in > performance critical paths?
? You use them all the time in SLUB alone.
> Didnt you want to do everything with order-0 > allocs?
People don't always do what I think is best, unfortunately ;)
> It seems that we currently need the slab allocators to compensate for the > performance problems in the page allocator for these higher order allocs. > I'd rather have the page allocator fixed but things are as they are.
No objections from me with speeding up the page allocator of course.
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