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/
