Messages in this thread | | | Date | Wed, 17 Apr 2019 13:27:43 +0000 | From | Christopher Lameter <> | Subject | Re: [PATCH 0/1] mm: Remove the SLAB allocator |
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On Wed, 17 Apr 2019, Jesper Dangaard Brouer wrote:
> I do think SLUB have a number of pathological cases where SLAB is > faster. If was significantly more difficult to get good bulk-free > performance for SLUB. SLUB is only fast as long as objects belong to > the same page. To get good bulk-free performance if objects are > "mixed", I coded this[1] way-too-complex fast-path code to counter > act this (joined work with Alex Duyck).
Right. SLUB usually compensates for that with superior allocation performance.
> > It's, of course, worth thinking about other pathological cases too. > > Workloads that cause large allocations is one. Workloads that cause lots > > of slab cache shrinking is another. > > I also worry about long uptimes when SLUB objects/pages gets too > fragmented... as I said SLUB is only efficient when objects are > returned to the same page, while SLAB is not.
??? Why would SLUB pages get more fragmented? SLUB has fragmentation prevention methods that SLAB does not have.
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