On Thu, 10 May 2007, Mel Gorman wrote:
> > I cannot predict how allocations on a slab will be performed. In order
> > to avoid the higher order allocations in we would have to add a flag
> > that tells SLUB at slab creation creation time that this cache will be
> > used for atomic allocs and thus we can avoid configuring slabs in such a
> > way that they use higher order allocs.
> >
>
> It is an option. I had the gfp flags passed in to kmem_cache_create() in
> mind for determining this but SLUB creates slabs differently and different
> flags could be passed into kmem_cache_alloc() of course.
So we have a collection of flags to add
SLAB_USES_ATOMIC
SLAB_TEMPORARY
SLAB_PERSISTENT
SLAB_RECLAIMABLE
SLAB_MOVABLE
?
> Another alternative is that anti-frag used to also group high-order
> allocations together and make it hard to fallback to those areas
> for non-atomic allocations. It is currently backed out by the
> patch dont-group-high-order-atomic-allocations.patch because
> it was intended for rare high-order short-lived allocations
> such as e1000 that are currently dealt with by MIGRATE_RESERVE
> (bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks.patch)
> The high-order atomic groupings may help here because the high-order
> allocations are long-lived and would claim contiguous areas.
>
> The last alternative I think I mentioned already is to have the minimum
> order kswapd reclaims as the same order SLUB uses instead of 0 so that
> min_free_kbytes is kept at higher orders than current.
Would you get a patch to Nicholas to test either of these solutions?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
