Re: [PATCH v2 2/2] SLUB: Mark merged slab caches in /proc/slabinfo

Pekka Enberg
2010-09-14T21:00:23Z

On 14.9.2010 23.56, David Rientjes wrote:
>> In my not-so-humble opinion, either the merging needs to go away
>> entirely, or the misleading output needs to be fixed.
> Cache merging may have been advertised as a bigger performance improvement
> than it actually is, and I don't do it in my own slab allocator for other
> reasons, but it does lead to more effective memory use by reducing slab
> fragmentation. On one of my benchmarking servers, over 60% of caches are
> merged and /sys/kernel/slab/.../partial reports roughly the same percent
> of fewer total partial slabs over the system in comparison to
> slub_nomerge.
Last time I checked (and it's been a while), it did reduce _internal
fragmentation_ for the naive "memory used after boot" scenario. I don't
think I ever advertised it as a performance improvement. Dunno if
somebody else did.

Pekka