On Thu, 28 Apr 2011, James Bottomley wrote: > > Since 4a5fa3590f09 ([PARISC] slub: fix panic with DISCONTIGMEM) from > > 2.6.39-rc4, you can't actually select slub on m68k without CONFIG_ADVANCED > > and CONFIG_SINGLE_MEMORY_CHUNK because it otherwises defaults to > > discontigmem. > > > > James tested hppa64 with my N_NORMAL_MEMORY fix and found that it turned > > an SMP box into UP. If you've tested slub on m68k without regressions, > > then perhaps you'd like to add a "|| M68K" to CONFIG_SLUB? > > To be honest, I really don't see that fixing it. As soon as you > allocate memory beyond range zero, you move onto a non-zero node as far > as slub is concerned, and that will oops. >
Possible nodes are represented in slub with N_NORMAL_MEMORY, so the kmem_cache_node structures are allocated and initialized based on this nodemask. As long as the memory ranges map to nodes set in the nodemask, this should be fine. > I think what the N_NORMAL_MEMORY patch did is just make it take a whiile > before you start allocating from that range. Try executing a memory > balloon on the platform; that was how we first demonstrated the problem > on parisc. > With parisc, you encountered an oops in add_partial() because the kmem_cache_node structure for the memory range returned by page_to_nid() was not allocated. init_kmem_cache_nodes() takes care of this for all memory ranges set in N_NORMAL_MEMORY. Adding Christoph and Pekka to the cc if there is additional concerns about slub on this architecture. -- To unsubscribe from this list: send the line "unsubscribe linux-m68k" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
