On Tue, 19 Jun 2007 18:06:16 +0900 Paul Mundt <[EMAIL PROTECTED]> wrote:
> This adds preliminary NUMA support to SLOB, primarily aimed at systems > with small nodes (tested all the way down to a 128kB SRAM block), whether > asymmetric or otherwise. > > We follow the same conventions as SLAB/SLUB, preferring current node > placement for new pages, or with explicit placement, if a node has been > specified. Presently on UP NUMA this has the side-effect of preferring > node#0 allocations (since numa_node_id() == 0, though this could be > reworked if we could hand off a pfn to determine node placement), so > single-CPU NUMA systems will want to place smaller nodes further out in > terms of node id. Once a page has been bound to a node (via explicit > node id typing), we only do block allocations from partial free pages > that have a matching node id in the page flags. > > The current implementation does have some scalability problems, in that > all partial free pages are tracked in the global freelist (with > contention due to the single spinlock). However, these are things that > are being reworked for SMP scalability first, while things like per-node > freelists can easily be built on top of this sort of functionality once > it's been added. > > More background can be found in: > > http://marc.info/?l=linux-mm&m=118117916022379&w=2 > http://marc.info/?l=linux-mm&m=118170446306199&w=2 > http://marc.info/?l=linux-mm&m=118187859420048&w=2 > > and subsequent threads. > > ... > > +static void *slob_new_page(gfp_t gfp, int order, int node) > +{ > + void *page; > + > +#ifdef CONFIG_NUMA > + if (node != -1) > + page = alloc_pages_node(node, gfp, order); > + else > +#endif > + page = alloc_pages(gfp, order); Isn't the above equivalent to a bare page = alloc_pages_node(node, gfp, order); ? > + if (!page) > + return NULL; > + > + return page_address(page); > +} > + > /* > * Allocate a slob block within a given slob_page sp. > */ > @@ -258,7 +290,7 @@ static void *slob_page_alloc(struct slob_page *sp, size_t > size, int align) > /* > * slob_alloc: entry point into the slob allocator. > */ > -static void *slob_alloc(size_t size, gfp_t gfp, int align) > +static void *slob_alloc(size_t size, gfp_t gfp, int align, int node) > { > struct slob_page *sp; > slob_t *b = NULL; > @@ -267,6 +299,15 @@ static void *slob_alloc(size_t size, gfp_t gfp, int > align) > spin_lock_irqsave(&slob_lock, flags); > /* Iterate through each partially free page, try to find room */ > list_for_each_entry(sp, &free_slob_pages, list) { > +#ifdef CONFIG_NUMA > + /* > + * If there's a node specification, search for a partial > + * page with a matching node id in the freelist. > + */ > + if (node != -1 && page_to_nid(&sp->page) != node) Other code does if (node < 0 rather than comparing with -1 exactly. On many CPUs it'll save a few bytes of code. - 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/
