Messages in this thread | | | Date | Tue, 23 Oct 2007 13:09:31 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: SLUB 0:1 SLAB (OOM during massive parallel kernel builds) |
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On Tue, 23 Oct 2007, Pekka Enberg wrote:
> On 10/23/07, Christoph Lameter <clameter@sgi.com> wrote: > > Not sure what this is. Maybe the slowing SLUB solves the race. > > What kind of race are you thinking of? What I initially thought was > that the problem is that SLUB messes up some other VM heuristics due > to different object sizes, not holding on to empty slabs, and/or page > allocator pass-through. I guess only object size is affected by > debugging, though?
The number of objects per page is reduced by enabling full debugging. That triggers a potential of more order 1 allocations but we are failing at order 0 allocs. slub_debug=F does not increase object size with debugging information but keeps things as they are while doing as much verification of slab integrity as possible.
One--potentially far fetched theory--is that the difference in alloc performance may trigger a race. But I guess it is more likely that we will find something wrong with the gfp flags (that I recategorized for 2.6.24).
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