Alan Cox wrote:
>
> > > doesn't matter which free page is used first/last.
> >
> > You're full of crap.
> > LIFO is obviously superior due to cache re-use.
>
> Interersting question however. On SMP without sufficient per CPU slab caches
> is tht still the case ?
Correct. SMP was perfect LIFO even without Andrea's changes.
I thought Andrea tried to reduce the fragmentation, therefore I wrote
"free is free".
But even for cache re-use his changes are not a big change: The main
fifo/lifo ordering on UP is mandated by the defragmentation property of
the slab allocator.
Afaics there is exactly one case where my code is not lifo and Andrea's
is: kmem_cache_free frees the last object in slab, each slab contains
more than one object, and there are no further partial slabs.
In all other cases Andrea just adds list_del();list_add() instead of
changes to the firstnotfull pointer.
full->partial is/was lifo,
partial->partial doesn't change the lists at all
partial->empty was fifo, is now lifo_if_no_partial_slab_exists
-- Manfred - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Sep 15 2001 - 21:00:19 EST