Messages in this thread | | | Date | Wed, 14 Jan 2009 12:01:32 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [patch] SLQB slab allocator |
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On Wed, 14 Jan 2009, Nick Piggin wrote:
> Right, but that regression isn't my only problem with SLUB. I think > higher order allocations could be much more damaging for more a wider > class of users. It is less common to see higher order allocation failure > reports in places other than lkml, where people tend to have systems > stay up longer and/or do a wider range of things with them.
The higher orders can fail and will then result in the allocator doing order 0 allocs. It is not a failure condition. Higher orders are an advantage because they localize variables of the same type and therefore reduce TLB pressure.
> The idea of removing queues doesn't seem so good to me. Queues are good. > You amortize or avoid all sorts of things with queues. We have them > everywhere in the kernel ;)
Queues require maintenance which introduces variability because queue cleaning has to be done periodically and the queues grow in number if NUMA scenarios have to be handled effectively. This is a big problem for low latency applications (like in HPC). Spending far too much time optimizing queue cleaning in SLAB lead to the SLUB idea.
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